首页 labview宝典第一章

labview宝典第一章

labview宝典第一章labview宝典第一章第章打开LabVIEW编程之门 LabVIEW在国内流行的时间并不长,只有短短的几年时间,但实际上它已经诞生20多年了,在国外被广泛用于教学、科研、测试和工业自动化领域。从LabVIEW 6.1版本后,LabVIEW开始流传开来,越来越多的编程人员开始使用LabVIEW并把它作为首选的编程语言。LabVIEW与常规编程语言有很大的不同,可以说它是专门为工程师开发设计的语言,专业性很强。对于从事工程应用的工程师们来说,LabVIEW是必须掌握的编程语言。由于LabVIEW的特殊...

labview宝典第一章第章打开LabVIEW编程之门 LabVIEW在国内流行的时间并不长,只有短短的几年时间,但实际上它已经诞生20多年了,在国外被广泛用于教学、科研、测试和工业自动化领域。从LabVIEW 6.1版本后,LabVIEW开始流传开来,越来越多的编程人员开始使用LabVIEW并把它作为首选的编程语言。LabVIEW与常规编程语言有很大的不同,可以说它是专门为工程师开发设计的语言,专业性很强。对于从事工程应用的工程师们来说,LabVIEW是必须掌握的编程语言。由于LabVIEW的特殊性,这里对于开始学习LabVIEW的朋友们,提出如下建议, , 要学会“背叛”。LabVIEW有自己独特的编程方式,要学会LabVIEW的思维逻辑。 , 不要相信两三个小时就能学会LabVIEW之类的话,即便是一年也只是入门而已。 , 任何时候要牢记“数据流”的概念,这是LabVIEW编程的核心。 , LabVIEW直接面向工程应用,因此“ 标准 ”是最重要的。 , LabVIEW是工程师的语言,编程者首先必须使自己成为一位优秀的工程师。 , 学习LabVIEW最好的资料就是LabVIEW的例子程序。 1.1 从VI开始 LabVIEW同其他编程语言和软件一样,安装程序界面友好、容易使用。将安装光盘插入到光驱后,自动启动LabVIEW安装。只要输入正确的序列号,所有的安装过程都能自动完成。安装结束后,重新启动计算机,然后用鼠标双击LabVIEW的快捷方式图标,即可启动LabVIEW。常规编程语言,如VB、VC的IDE开发环境,都是从新建一个具体的项目开始的,而LabVIEW的第一项是新建VI,显然VI对LabVIEW来说是非常基本和重要的概念。LabVIEW启动窗口如图1-1所示。图1-1 LabVIEW启动窗口新建一个VI后,呈现在我们面前的是两个常见的Windows窗口,分别为前面板窗口与程序框图窗口,如图1-2所示。我们在后面的讲述中将这两个窗口简称为前面板和程序框图。 VI由前面板和程序框图组成。一般常规编程语言创建的程序,由一个图形界面窗口,一般称为GUI,和文本编辑窗口组成。and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 第章打开LabVIEW编程之门 LabVIEW中的VI,前面板相当于GUI,程序框图则相当于文本编辑器。显然,前面板是需要放置各种控件的,而程序框图是用来编写代码的。LabVIEW最大的特点是图形式编程语言,也就是说它的代码是完全图形化的,和常规的文本式编程语言截然不同。通过菜单栏的“工具”菜单,可以调出控件选板和函数选板,如图1-3所示。其中控件选板用于在前面板放置控件,函数选板用于在程序框图中放置函数,即代码,。图1-2 前面板窗口和程序框图窗口图1-3 控件选板和函数选板 LabVIEW给人的第一感觉,是控件的数量和种类远胜于其他编程语言。例如,在VC中要找到一个不同于Windows标准的控件是很困难的,有时候不得不采用“自画”的方式实现。另外一个明显的不同是,LabVIEW的控件分成输入控件和输出控件两部分,输出控件又称为显示控件。控件选板和函数选板的使用非常频繁,而使用菜单来调用它们非常不方便。最简单的调用方法是,右击前面板,弹出控件选板,右击程序框图,弹出函数选板,然后按快捷键Ctrl+E,即可快速在前面板和程序框图之间切换。 1.1.1 创建VI 常规语言的入门程序一般是经典的“Hello World，”,即在显示窗口放置一个显示控件,一般是文本框,然后给这个文本框赋值。这里,我们也从“Hello World”VI的创建开始。要输出字符串“Hello World”,首先需要在前面板放置字符串显示控件。通过控件选板,选择字符串显示控件。此时出现一个带虚框的控件,将其移动到前面板合适的位置。单击前面板,字符串显示控件就会自动放置在前面板中。在前面板放置显示控件后,在对应的程序框图中自动出现对应的接线端子,如图1-4所示。接线端子是LabVIEW特有的概念,它与前面板控件一一对应。双击前面板中的控件或者程序框图中的接线端子,可以自动定位到对应的接线端子或控件。在快捷菜单中,通过查找控件或者接线端子,也可以实现同样目的。现在遇到的问题是如何给这个显示控件赋值。记住,数据流是LabVIEW编程的核心。作为字符串显示控件,它是数据要流动到达的目标。因此,必须有一个数据流出的源。我们自然想到,字符串输入控件就是数据源。用同样的方法,在前面板放置一个字符串输入控件。接下来我们需要考虑如何在输入控件和输出控件之间建立联系。在LabVIEW中创建程序框图的过程就相当于用常规语言编写代码的过程,输入控件接线端子和显示控件接线端子之间连线的过程,就相当于用常规语言编写语句的过程。前面板和程序框图的操作都离不开工具选板,所以在连线之前首先要熟悉一下工具选板,如图1-5所示,如果工具选板未显示,通过菜单栏中的“工具”菜单可以调出工具选板。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 3 LabVIEW 在工具选板中,当鼠标箭头移动到工具按钮上时,会出现工具条提示。工具选板上各个按钮的名称和详细功能,如表1-1所示。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 4 第章打开LabVIEW编程之门图1-4 放置字符串显示控件图1-5 工具选板表1-1 工具条提示图标名称功能选中后,根据鼠标位置自动确定工具,按Shift+Tab组合键或自动选择工具单击此按钮可以禁止或者启动自动选择工具改变控件值。对于数值型控件,可以直接控制增减量,对于字操作值符串,可以直接输入或者更改字符串处于箭头状态时,通过双击控件或者接线端子,可以定位到接定位/调整大小/选择线端子或者控件,选中对象后,可以拖动改变其大小,还可以通过矩形框选择一个或者多个对象编辑对象标签、标题或自由标签,也可以用来改变数值型控件编辑文本的值进行连线仅用于程序框图,用于对象之间的连线与用鼠标右键选取快捷菜单的功能相同,主要用于同时修改多对象快捷菜单个控件的属性滚动窗口 Windows常规操作,用于平移滚动窗口在VI、函数、节点、连线和结构上设置或清除断点,使程序在设置/清除断点断点处暂停探针数据在连线上设置探针,可以观察流动的瞬时数据,主要用于调试获取颜色取得当前窗口任意位置的颜色设置颜色设置对象元素的颜色,可以和获取颜色配合使用通过连线工具创建的“Hello World”VI,如图1-6所示。 LabVIEW中的VI类似一个函数,但是与C语言中的函数有明显区别。用常规编程语言编写的程序都有一个明显的入口点,比如main()函数。VI则不同,任何一个VI都是可以单独运行的,不存在明显的入口点。用常规编程语言编写代码后,需要明显的编译、连接过程,VI则不存在明显的编译过程,在我们对VI程序框图连线时,编译过程在后台自动发生,编译过程是动态的。单击工具栏中的“运行”按钮,运行VI,输入字符串控件当前的值将自动显示到字符串输出控件中。输出控件经过连线,把它的值传递给显示控件。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 5 LabVIEW 工具栏中还提供了“连续运行”和“中止”按钮,如图1-6所示。这里要介绍一下“运行”和“连续运行”的区别,“运行”是程序运行一次就结束了,而“连续运行”是指VI连续不断循环运行。“连续运行”可以修改输入控件的值,而且显示控件能显示出动态修改的结果,当VI连续运行时只能通过单击工具栏的第3个按钮“终止运行”来结束。下面在图1-6所示VI的基础上,创建计算一次函数y=kx+b的VI,y作为计算结果输出,k、x、b作为参数输入。如图1-7所示,数值控件使用的是双精度数据类型,它的连线颜色与字符串明显不同。从连线的颜色和线型,可以明显区分数据类型,这是LabVIEW图形编程方式的突出特点。图1-6 “Hello World”VI 图1-7 一次函数不同颜色、不同的线型表示不同的数据类型。当程序框图中出现未连线或连线错误时,工具条上的“运行”按钮就变成“错误”按钮。单击它会自动弹出错误列表对话框,提示出现的错误,而常规编程语言在编译的过程中提示错误,这说明LabVIEW的编译过程是在后台自动完成的。 LabVIEW程序的编译是在连线的过程中自动进行的。 LabVIEW称做“G”语言。G指的是Graphical Programming Language,即图形化编程语言。对照其他文本方式的编程语言,G语言中键盘的作用似乎不重要了,因为在程序框图中既看不到变量,也看不出任何语句的存在。我们完全可以理解前面板中控件的含义,这和其他编程语言一样。GUI是由各种各样的控件集合成的,但是它的控件有独特之处,一是数量多,二是明确区分输入控件和输出控件。 “数据流”是LabVIEW的核心,也是G语言的核心了。输入控件和显示控件中间的连线就表明了数据是由输入控件流动到显示控件。输入控件就是数据的“来源”,显示控件就是数据要流动到的“目的地”,而这个流动的过程是通过连线完成的。与日常的物理现象中的“流动”不同的是,流动后,输入控件的数据并没有“损耗”,依然存在,而显示控件的数据被“冲掉”了,变成了新的数据。既然是数据流,那么一点的数据应该可以流向多点,多点的数据也应该可以汇集成一点。实际上,上面的程序已经实现多点汇集到一点了,一次函数y=kx+b,k、x、b都是输入控件,是数据源,而目的地是y,这本身就是多个输入控件的数据汇集到一个显示控件。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 6 第章打开LabVIEW编程之门 1.1.2 控件属性设置与快捷菜单通过前面的学习,我们初步了解了LabVIEW程序是由VI组成的,而VI又是由输入控件、显示控件和数据连线组成。因此,深入了解和探讨控件是非常必要的。LabVIEW的控件种类繁多,即使是同一类型控件,在一些细节上也有很大差别。 VB、VC也提供了大量的控件,如命令按钮、文本框、列表框和组合框等。LabVIEW提供的控件与众不同。首先,控件分成输入控件和显示控件,另外,控件的分组也很有特点。控件由数值控件、布尔控件、字符串和路径组、数组矩阵组、列表与表格组、图形组等组成。这不像普通的控件分组,更像是变量的数据类型分组。 1,控件的基本属性一般的控件具有属性、方法和事件,LabVIEW的控件与常规控件类似,它也具有属性、方法和事件。一般的控件都包括“值”的属性,表示控件当前代表的数值或字符串等,也就是说控件是数据的容器,而数据的值只是控件属性之一。 LabVIEW中不存在常规语言中变量的说法,任何数据都是依附于控件的。控件是数据的容器,数据不能离开控件而独立存在,移位寄存器和常量是例外,。 LabVIEW的控件中包含数据,但是数据是有类型区别的,比如数字可以是整型,而整型又可以分成有符号和无符号、8位、16位、32位等。选定数据类型后,控件与数据类型就存在了对应的关系,不允许动态更改。控件作为对象,由多个组成要素构成,比如标签、标题、颜色、字体等。对于一个具体的控件,通过快捷菜单或属性对话框,可以修改其属性。不同种类的控件专用属性可能不同,但是其常规属性基本相同。这里以字符串控件的属性对话框为例,介绍常见的基本属性。在控件的快捷菜单中选择“属性”,弹出属性对话框,字符串属性对话框如图1-8所示。字符串属性对话框采用典型的选项卡方式,其中包括“外观”、“说明信息”、“数据绑定”、“快捷键”和“安全”5个类别。按照常规的表示方法,位于上方的属性一般是通用属性,而位于下方的往往是控件的专用属性。 ,1,“外观”选项卡上的属性用于控制控件显示的有关特征,控件的通用外观属性包括以下几点。 , 标签和标题,标签代表的是控件的名称,它在运行过程中属于只读属性,不能在运行过程中更改,相当于常规语言中的变量名。标题是控件显示给用户的信息,属于可读写属性,在运行过程中可以随时更改,一般多语言环境的软件都是采用类似的方法。 , 大小,包括高度和宽度,表示的控件大小信息。通过高度和宽度,可以精确控制控件的大小。图1-8 字符串属性对话框 , 启用状态,包括“启用”、“禁用”和“禁用并变灰”三个单选按钮。它们用于表示控件的状态信息,处于禁用状态的控件不接受键盘和鼠标操作。控件的标签是内部名称,用于区别控件,而标题是用于人机交互的。 ,2,属性对话框的第二个选项卡页面为“说明信息”,由说明和提示框两部分组成。说明和提 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 7 LabVIEW 示框输入的是文本信息。 , 提示框内输入的内容就是通常所说的“工具条提示”,当移动鼠标箭头到控件上时,不执行任何操作,几秒后即出现“提示框”里的说明文字。 , “说明”是控件的详细信息,可以对控件做详细解释。程序运行时,用鼠标选择控件,然后在右键快捷菜单中选择“说明”,就会弹出一个对话框,显示的就是我们输入的“说明”信息。在LabVIEW中文本输入的手动换行是通过快捷键Shift+Enter实现的。 ,3,其他选项卡,比如数据绑定、安全等,将在后续章节介绍。 2,输入控件和显示控件的区别 LabVIEW控件明显分成了输入控件和显示控件两大类别。LabVIEW作为一种用于工程的编程语言,是与测试测量和自动化控制密切相关的。从硬件的角度看,控件分成这两大类非常合适。以自动化控制为例,它的输入和输出是有明显区别的。比如继电器是输出类型的,而检测开关则是输入类型的。广泛使用的数据采集卡也分成模拟量输入和模拟量输出、数字量输入和数字量输出。从LabVIEW本身的编程特点来说,数据流是LabVIEW的核心概念,任何数据必须是有“源”的,这个“源”就是输入控件或者常量,常量可以理解成特殊的输入控件,而数据最终流向地就是显示控件。从控件本身的角度来看, LabVIEW其实只是推荐了控件的使用方法,并没有绝对地区分控件必须是输入控件还是显示控件。比如数值控件中有“旋钮”和“量表”。旋钮是输入控件,而量表是显示控件。这与现实情况是非常符合的。对于收音机的音量控制,确实有个物理的旋钮存在,而对音量,比较高级的收音机也确实有个简单的电子仪表来显示。 LabVIEW的输入控件和显示控件是可以自由转换的。在控件的快捷菜单中就可以实现将输入控件转换成显示控件,或者将显示控件转换成输入控件。但这只是在程序编辑情况下才可以,在程序运行情况下是不允许转换的。如果允许的话,数据流的流向就会发生变化,这将导致数据流无法实现。 3,控件快捷菜单 LabVIEW对控件的许多操作都是通过快捷菜单实现的,所以有必要深入研究一下快捷菜单。对于不同的控件,快捷菜单既有相同的部分,也有不同的部分。相同的部分适合所有的控件,而不同的部分对应着控件的特殊属性。以一个旋钮控件为例看一下控件的快捷菜单,如图1-9所示。显示项中包括标签和标题,这是控件的通用基本属性。通过这个菜单可以选择控件标签以及标题是否可见,前面我们通过属性对话框同样可以设置这两个属性。如果只想设置控件的部分属性,直接用快捷菜单比较方便。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 8 第章打开LabVIEW编程之门图1-9 旋钮控件的快捷菜单显示项中还有单位标签、数字显示和梯度三个选择项,图1-10演示了它的不同效果。图1-10 旋钮控件的不同显示效果通过上面的效果图我们可以看到,一个LabVIEW控件由不同的可显示部件组成,比如上面的旋钮,就是由旋钮、单位标签、数字显示和梯度等几个部件组合而成,而其中每一个独立的部件都可以分别设置它的属性,比如颜色、字体等。 1.1.3 创建控件、常量、局部变量、引用、属性节点和方法节点创建控件、常量、局部变量、引用、属性节点和方法节点,是LabVIEW中极为常见的操作,使用得非常频繁。创建方法很多,分类介绍如下。 1,创建控件 LabVIEW的控件数量庞大,种类繁多,这极大地方便了GUI设计。控件从基本显示风格来区分,可分成“新式”、“古典式”和“系统”三大类。 , 新式控件是三维显示风格,LabVIEW推荐使用此类控件。 , 古典控件是平面显示风格,早期LabVIEW使用此类控件。 , 系统显示风格,适用于编写Windows风格的应用程序。任何一种编程语言都具备处理复杂数据类型的能力,LabVIEW作为成熟的编程语言,自然也不例外。在各种编程语言中最常见的复杂数据类型为数组和记录,VB,或结构,C语言,,LabVIEW中类似记录或结构的数据类型,称为“簇”。这只是一个称谓的区别,本质并无区别。在控件选板中包含数组和簇控件,但它们是作为控件形式出现的因此,它们的创建方式与数值控件相同。在控件选板选择数组和簇之后,前面板会出现数组和簇的容器,之后我们需要在数组或者簇中添加元素。对于数组,数组中的元素具有相同的属性,因此只需要选择需要的元素控件类型。建立数组容器后,右击容器内空白处,弹出控件选板,选择合适的控件。也可以在前面板放置控件,然后拖动到数组容器中,簇的建立方法类似,不过需要选择多种控件。控件隶属于特定的前面板,前面板往往包括多种不同类型的控件,创建控件有多种方法。 , 在控件选板中选择相应的控件,然后拖动到前面板,程序框图中就会出现相应的接线端子。 , 在程序框图函数接线端子上打开快捷菜单,选择“创建”,“输入控件”或“创建”,“显示控件” 项。 , 通过剪切板,复制一个或者多个控件。同常规的Windows程序一样,LabVIEW提供了剪切板功能,可以通过“编辑”菜单来完成,不过更方便的方法是使用快捷键。使用快捷键 Ctrl+C,可以复制控件或控件集合。使用快捷键Ctrl+X,可以剪切控件或控件集合。使 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 9 LabVIEW 用快捷键Ctrl+V,可以粘贴控件或控件集合。 , 用鼠标左键选择控件或控件集合,按下Ctrl键后拖动鼠标,可以直接生成新的控件或控件集合,这种方法称为克隆。 , 在程序框图中,选择接线端子或者接线端子组,然后按下Ctrl键后拖动鼠标,可以直接在前面板上创建新的控件。 , 从已经打开的别的VI前面板上,直接拖动控件或者控件集合到前面板。 , 从已经打开的别的VI的程序框图中,直接拖动接线端子或者接线端子组,可以包括连线, 这样可以直接复制程序,并自动创建相应控件。 2,创建常量常量隶属于程序框图,在程序框图创建常量有以下几种方法。 , 在函数面板上找到相应的函数,比如数值、字符串、文件路径、数组或簇,其中都包括常量。 , 在接线端子的右键快捷菜单中,选择“创建”,“创建常量”项。 , 拖动前面板上的控件或控件集合到程序框图,直接创建与控件类型对应的常量。 , 在类似的常量存在的情况下,通过剪切板复制、剪切和粘贴来创建常量。 , 在类似的常量存在的情况下,按下Ctrl键后用鼠标拖动该常量,通过克隆原来的常量来创建新的常量。 , 在已经打开的其他VI中,直接拖动控件或者常量到程序框图。 , 在局部变量的右键快捷菜单中,选择“创建”,“创建常量”项。 , 在属性节点的右键快捷菜单中,选择“创建”,“创建常量”项。其中有些常量,比如数值常量,可以通过快捷菜单进一步选择相应的数据类型,比如U8、I16、 DBL等,。 3,创建局部变量局部变量的具体含义将在后续章节介绍,创建局部变量的几种方法如下。 , 最基本的方法是在控件或者接线端子的右键快捷菜单上,选择“创建”,“局部变量”项。 , 对于已经存在的局部变量,通过剪切板复制局部变量是不可行的,需要特别注意。 LabVIEW虽然支持局部变量的复制、剪切和粘贴操作,但是粘贴后会创建一个新的控件及其局部变量。 , 对于已经存在的局部变量,可以按下Ctrl键后用鼠标拖动局部变量来克隆。 4,创建属性节点属性节点具体内容将在后续章节介绍。创建属性节点有如下方法。 , 最基本的方法是使用前面板控件或程序框图中的接线端子的右键快捷菜单,选择“创建”,“属性节点”项。 , 对于已经存在的属性节点,通过剪切板复制、粘贴的并非原来控件的属性节点,而是和原来数据类型对应的通用属性节点,暂时未指向任何控件。 , 最简单的方法是按下Ctrl键后拖动用鼠标属性节点,创建一个新的属性节点。选择现有的属性节点,通过复制粘贴可以创建严格类型的通用属性节点。按 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 10 第章打开LabVIEW编程之门下Ctrl键后用鼠标拖动该节点即可对其克隆,克隆操作不产生新的控件。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 11 LabVIEW 5,创建控件的引用创建控件的引用有如下方法。 , 最基本的方法是在控件或者接线端子的右键快捷菜单上,选择“创建”,“引用”项。 , 对于已经存在的控件的引用,按下Ctrl键的同时用鼠标拖动控件引用来克隆。 , 对于已经存在的引用,通过剪切板复制、粘贴的并非原来控件的引用,而是和原来控件类型一致的新的控件和控件的引用。 6,创建控件的方法,中文版的帮助文件中称做调用节点,早期文档中译为“方法”, LabVIEW的控件与其他编程语言的控件一样具有属性和方法。创建控件的方法有以下几种方式。 , 最基本的方法是在控件或者接线端子的右键快捷菜单中,选择“创建”,“方法”项。 , 对于已经存在的控件方法,按下Ctrl键后拖动该方法来克隆。 , 对于已经存在的控件方法,通过剪切板复制、粘贴的并非原来控件的方法,而是和原来控件类型一致的新的通用控件方法。选择现有的方法,通过复制、粘贴可以创建严格类型的通用方法。以上介绍了控件、常量、局部变量、属性节点、引用和方法的创建方法,其中都包括了按下Ctrl键拖动鼠标的方法。这种方式称做“克隆”,克隆与Windows的复制、粘贴是不同的。Windows里的复制和粘贴往往创建新的控件,而克隆操作往往创建的是同一控件的局部变量或者属性节点等。控件和常量可以通过子VI的接线端子的快捷菜单,选择“创建”,然后选择“输入控件”、“显示控件”或者“常量”,来创建所需的输入控件、显示控件。利用这种方法,可以保证控件和子VI端子需要的类型一致,这是非常重要的功能。选择子VI的端子,通过快捷菜单选择“创建”项,来创建控件和常量。 1.1.4 创建自定义控件在选择控件之后,可以通过快捷菜单中的“表示法”项或者属性对话框来选择控件所代表的数据类型,一般都是一类相近的数据类型。比如数值类型中,U8、I8、U16和I16都是相近的数据类型。这样,在设计过程中想更改数据类型是很容易的。如果设计的数据类型和实际需要的数据类型有很大区别,这时可以直接选择快捷菜单中的“替换”项,把原来的控件替换成想要的新形式。在构造一个比较复杂的程序时,通常要定义一个复杂的数据结构来描述外部现象,而这个复杂的数据结构有可能贯穿整个程序的始终。一旦这个数据结构发生变化,将导致程序多处发生变化,这会给程序设计者造成极大困难,甚至导致整个程序设计的失败。最好的方法是定义一个统一的复杂数据类型,通常是用构造簇的方法来实现,让簇作为一种统一的数据类型,贯穿程序设计的始终,。通过这种方法,对数据结构的修改就能在程序中所有引用簇的地方自动更新。LabVIEW是通过把簇控件作为自定义控件来实现这个要求的。在控件的快捷菜单中,选择“高级”,“自定义”项,可以自定义任何控件。一个控件包括外观、数据类型、控件默认值等内容,可以自定义的是控件的哪些部分呢,如果自定义的仅仅是控件的外观,那意义不大,无非是为控件新增了特殊的显示效果。LabVIEW在这方面做得已经足够多了,很容易找到所需的控件。选择一个控件,打开快捷菜单并选择“自定义”项,弹出自定义控件编辑器,看看到底能自定义哪些部分。如图1-11所示,这是一个普通的数值控件自定义前面板,它与普通的前面板是有区别and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 12 第章打开LabVIEW编程之门的。一般VI的前面板对应一个程序框图,而自定义控件面板没有对应程序框图,不允许编程。此外还可以看出,一个控件是由一些基本对象元素组合而成的,每一个元素都可以独立修改,如颜色、大小等。重新定义这些基本元素,就可以构造出新的符合自己特殊要求的控件。自定义控件有三种形式,输入控件、自定义类型和严格自定义类型,如图1-11所示。自定义控件的三种不同形式存在重要区别。图1-12分别调用了创建后的输入控件、自定义类型、严格自定义类型的属性对话框,我们可以发现,其属性对话框存在明显区别。输入控件、自定义类型、严格自定义类型的区别如下所述。 , 输入控件保存在一个单独文件中,对于保存为输入控件方式的自定义控件,一旦在一个 VI中调用它,则这个新生成的控件与原来的控件没有任何关系,可以自由地修改这个新控件的属性,如图1-12中左侧图所示。图1-11 自定义控件编辑器图1-12 输入控件、自定义、严格自定义属性对话框 , 自定义类型和严格自定义类型的自定义控件则与输入控件型不同,在一个VI中调用这两类自定义控件后,新生成的控件保持和文件中存储的自定义控件的链接关系。任何对文件中存储的自定义控件进行修改后,所有调用这个自定义控件的VI都会更新。这样就保证了一个精心设计的复杂数据类型在所有调用VI中保持同步更新。 , 自定义数据类型和严格自定义数据类型的区别在于控件数据类型保持一致的程度。对于严格定义的数据类型,在调用它的VI中,除了可以修改是否可见、是否启用之外,无法对控件进行任何其他修改,完全保证和存储在文件中的自定义控件的高度一致,如外观、代表的数据类型、数据类型的精度、数据类型的输入范围等。而自定义数据类型除了外观和代表的数据类型保持一致外,其他属性可以自由设置。图1-12中,中间的图为自定义数据类型,右侧的图为严格自定义类型。可以使用自定义类型或者严格自定义类型构造通用或者复杂的数据类型。 1.2 编辑前面板和程序框图 LabVIEW的前面板从基本用途上可以分为两类,GUI人机交互界面和程序员交互界面,GPI,。GUI是直接显示给操作者使用的,对编程者来说最为重要。GUI针对不同领域的具体要求,有不同的设计标准。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 13 LabVIEW GPI和GUI则完全不同,GPI是展现给程序员看的。对于多个程序员互相协作的项目,程序员交互界面也是非常重要的,也要遵循一定的标准。不过与GUI的标准不同,GUI需要满足的是行业的标准规范 ,而GPI是LabVIEW程序员的“潜规则”,并不是必需的。因此也是仁者见仁,智者见智,不同的人有不同的理解。但是无论如何,清晰、整洁是最基本的要求。同VC、VB等流行的常规编程语言一样,LabVIEW也提供了有关控件布局方面的功能。由于LabVIEW是图形式编程语言,这方面的功能更加强大。 1.2.1 选择、移动和删除对象前面板、前面板上的控件、程序框图上的接线端子、函数、图标、连线等统称为对象。所谓编辑前面板和程序框图,就是编辑这些具体的对象。我们从前面板上的控件对象开始介绍,首先需要了解的是如何选取和移动对象,前面板控件的选择和移动的方法对程序框图同样适用。选择对象有多种方法,简单分类如下。 1,选择单个对象通过工具选板的“定位/调整大小”工具按钮选择。单击某个对象,则该对象被选中。对象被选中时,周围出现虚框。在任何情况下,采用矩形框选方式,可以直接选中对象。 2,选择多个对象通过选取工具选板的“定位/调整大小”按钮选择。单击选中某个对象,然后按住Shift键,选择其他对象,形成对象集合。在任何情况下,采用矩形框选方式,可以直接选中多个对象。 3,筛选对象筛选对象是在选择多个对象的基础上,在按下Shift键的同时,单击对象,将对象添入或剔出对象选择集。如果原来对象是选中的,则剔除该对象,如果原来对象处于未选中状态,则添加到选择集中。通过虚框很容易判断对象是否被选中。 4,选择全部对象选择全部对象,当然也可以采用矩形框选的方法,不过利用快捷键Ctrl+A更简单。使用快捷键Ctrl+A,可以选择前面板或程序框图中的全部对象。 5,移动对象移动对象属于常用的编辑操作。在单选或多选对象后,直接拖动其中任何一个对象,则出现一个新的虚框,随鼠标的运动而移动,虚框的位置表明当前位置。将虚框移动到合适位置释放鼠标后,原来位置上的对象将消失,而被移动到鼠标指定位置。如果移动之前按住Shift键,则可以保证移动沿水平方向或者垂直方向进行,方向取决于最开始的移动方向。采用键盘的方向键也可以移动选中的对象,而按住Shift键,则可以快速移动对象。 6,取消移动操作克隆对象和移动对象都涉及中间取消的问题,取消克隆和移动操作有以下几种方法。 , 执行完毕后,在“编辑”菜单中选择“取消”项,快捷键是Ctrl+Z。 , 克隆和移动过程中,按下Esc键,取消操作。 , 直接拖动到前面板窗口或者程序窗口外,取消操作。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 14 第章打开LabVIEW编程之门在克隆和移动对象的过程中,按下Esc键可以取消操作。按下Shift键,可以沿水平或者垂直方向移动对象或者对象集合。 7,精确移动对象移动对象时既可以用鼠标拖动,也可以用键盘操作。利用键盘方向键可以做比较精确的调整,按下Shift键可以快速移动对象或者对象集合。选择和移动对象,如图1-13所示。通过键盘移动对象时,按下 Shift键可以快速移动。 8,删除对象除了对象的创建、选择、移动、复制等操作, 对象的删除也是经常用到的操作。选择要删除的对象或者对象集合,然后通过以下几种方法来删除。 , 在菜单栏的“编辑”菜单中,选择“从项目中图1-13 选择和移动对象删除”。 , 利用Windows的剪切命令,快捷键为Ctrl+X。 , 选择对象或者对象集合后,按下Del、Delete、Backspace三者中的任何一个。 , 对象中包含的子元素,如控件的标签、标题等,,是不能单独删除的,只能选择“显示”或者“隐藏”。 1.2.2 使用布局工具前面板和程序框图有关布局的工具条是相同的,共有三个分类,对齐对象、分布对象和重新排序。其中每个分类中又有很多不同的子分类,下面我们分别介绍一下。 1,对齐对象顾名思义,对齐对象是指将一组被选择的对象按照一定要求对齐排列,分成上边缘、下边缘、左边缘、右边缘、垂直中心和水平居中几种方式,如图1-14所示。一般的控件对象默认都是显示标签的,各种对齐方式也是包括标签的对齐。标签默认位于对象的上方,如果我们移动了某个控件标签的位置, 而对齐对象有可能是以标签为基准的,此时要特别注意。不过,标签是可以单独选择的,首先要对齐控件本身,然后再对齐标签或者标题。图1-14 对齐对象前面板和程序框图都具有网格对齐功能。默认情况下,前面板是显示网格线的,而程序框图不显示网格线,可以通过“编辑”菜单或者快捷键Ctrl+#切换是否网格对齐。在创建控件时,一般采用网格对齐方式。在对齐时,先对齐对象,后对齐标签或者标题。快捷键Ctrl+#用于在前面板或程序框图中切换是否网格对齐。 2,分布对象各种分布对象的工具如图1-15所示。当我们将鼠标定位到某一个图标时,上方会出现说明文and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 15 LabVIEW 字,比如图1-15左上角第一个图标显示的文字是上边缘。结合它的图标很容易看出,它是以对象的上边缘为基准,沿垂直方向均匀分布的。需要注意的是,图1-15最右边上下两个图标分别是垂直压缩和水平压缩。选择这两个选项,可以使所有选择的对象沿垂直方向或水平紧密排列。紧密排列功能在程序框图设计中使用得非常广泛。这里以程序框图为例,简单地说明一下对齐和分布的使用方法。首先选择要对齐的对象集合,用矩形框选方式,选择“对齐对象”中的“左边缘”。然后选择“分布对象”中的“垂直压缩”,这样输入控件对象的排列就完成了,具体操作如图1-16所示。图1-15 分布对象图1-16 左边缘对齐,垂直压缩分布对于前面板中的对象采用同样方法,进行对齐和垂直压缩后,极大地节省了前面板和程序框图的空间,同时使连线变得更加简单整洁。对齐、分布是LabVIEW程序员必须掌握的基本技能,整理后的效果如图1-17所示。图1-17 左边缘对齐,垂直压缩分布效果图 3,调整大小创建一个对象后,经常需要修改其大小,尤其是前面板对象,比如输入控件、显示控件和装饰等。移动光标到某个控件上,如果光标指针是常见的箭头方式,表示目前的工具是定位/调整大小/选择状态。如果控件的大小允许调整,对象的四周和中间会出现方框标记,表示这个方向可以调整大小。移动光标到方框标记上,光标箭头变成缩放状后,按住鼠标左键沿某一方向拖动,就可以更改对象的大小了。这里的对象不仅仅指控件对象,也包括标签、标题等其他元素。但是采用鼠标拖动的方法,无法精确控制对象的大小尺寸。在开启网格对齐的情况下,鼠标定位的最小单位是一个网格。一个网格到底是多少呢,首先我们需要确定的是网格大小的基本单位是什么,无论是前面板还是程序框图,或者前面板和程序框图中的对象,都是以像素点作为基本单位的。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 16 第章打开LabVIEW编程之门 LabVIEW中对象的大小是以像素点作为基准单位的。 LabVIEW前面板和程序框图中的网格大小是可以设置的。默认情况下,前面板的每个网格为12个像素点,程序框图网格为16个像素点。对于新创建的VI,可以在菜单栏中选择“工具”,“选项”, 打开“选项”对话框,如图1-18所示。在这里,可以查看和设置网格大小。图1-18 “选项”对话框在这个对话框中,我们不但可以设置网格的大小,还可以设置网格相对于背景的对比度。当我们新创建一个对象时,新对象是有默认大小的。而这个默认大小可能不是网格对齐的,开启“缩放新对象以匹配网格大小”功能,可以强制新创建的对象调整大小尺寸,自动适应网格大小。另外,有的对象无法在水平和垂直两个方向同时对齐,这时LabVIEW会自动选择一个合适的方向单方向对齐。前面板默认网格为12个像素,程序框图默认网格为16个像素。 LabVIEW的前面板和程序框图并没有直接显示每个对象的大小,不过可以通过以下方法查看控件对象的大小。 , 在快捷菜单上,选择“属性”,然后在打开的“属性”对话框中查看当前控件对象的大小。 , 单击工具栏中的“调整对象大小”按钮,弹出“调整对象大小”对话框,如图1-19所示。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 17 LabVIEW 图1-19 “调整对象大小”工具按钮和“调整对象大小”对话框在上述对话框中不仅可以查看到控件对象的大小,更重要的是可以按照像素点修改控件对象的大小,其中有的对象只允许单方向调整。图1-19所示的例子就只允许调整对象的宽度。 “调整对象大小”对话框是个较常用的对话框,在其中不仅可以查看和调整单个对象的大小,更还可以同时调整对象集合,使对象集合中的对象具有同样的宽度或者高度。 “调整大小”工具栏中其他几个按钮非常容易理解,都是作用于所选取的对象集合的,其功能分别为设置最大宽度、最小宽度、最大高度、最小高度。 4,重新排序工具栏中有关对象布局的最后一项是重新排序,它包括3项基本功能。 ,1,组合功能相关的对象可以组合成一个组,作为一个单独的对象,统一进行复制、移动、删除等编辑操作,组中包含的对象的相对位置保持不变。在一个包含大量对象的界面中,采用对象组合是非常必要的。对于已经对齐、大小调整好的对象,难免会出现误操作,比如移动了不应该移动的控件,而后续又执行很多的操作。这时如果想恢复到移动前的状态,不得不执行编辑菜单中的撤销操作,而撤销操作是一步步进行的,这样出现错误后所有有用的编辑操作都被撤销了。在一个复杂的界面中重新分布对象也是非常困难的,因此非常有必要在一些对象元素完成编辑后,将它们组合成一个组。通过组合成组的方式,可以非常方便地实现GUI界面模块化。图1-20中,四个方向键分别控制上、下、左、右四个方向。这几个控件对象的大小相同,功能相似,它们组合在一起后,可以统一地移动,而相对位置保持不变。图1-20 对象组合 ,2,锁定锁定与组合不同,组合是针对对象集合的,一个单一的对象是不可能组合的,而锁定功能既可以针对单一对象,也可以作用于整个对象组合。锁定后,不允许对被锁定对象进行任何编辑操作,包括移动、删除、克隆等,甚至无法调用属性对话框修改属性。如果要编辑对象,必须通过“解锁”操作解除锁定,然后才能自由编辑锁定的对象。对象编辑完成后,组合和锁定对象或者对象集合,可以有效防止误操作。 ,3,重新排序 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 18 第章打开LabVIEW编程之门 LabVIEW并没有像某些软件一样在窗口显示对象的坐标,原因在于前面板的坐标原点是相对的、可移动的,并不能真正体现对象相对于前面板窗口的绝对位置。仔细观察LabVIEW的前面板,有两条网格线比较特殊,它们是加深显示的,并且显示一个交叉黑点。这个交叉点就是前面板窗口客户区的坐标原点。之所以强调前面板窗口客户区,是因为前面板也是一个窗口。它也具有宽度和长度属性,它本身的位置属性也是由一个点的坐标簇构成的,不过这个坐标是相对于计算机桌面的。 LabVIEW的对象对于垂直于屏幕的方向是有次序的,它按照对象的创建次序自动分配。越往后创建的对象相对于操作者“越近”,或者说它的次序越高。如果发生对象重叠的情况,次序高的对象将全部覆盖或者部分覆盖次序低的对象。 LabVIEW可以通过工具栏中的“重新排序”按钮来调整相对于操作者的对象的显示次序,效果如图1-21所示。图1-21 对象组合、锁定及改变次序 1.3 VI及其属性对话框在C语言中,函数是程序的基本单元,一个函数包括输入参数、输出参数和返回值。LabVIEW中VI的概念和函数非常相似,它的输入参数就是输入控件,它的输出参数就是显示控件,C语言的函数只能有一个返回值,而LabVIEW的VI可以有多个返回值,LabVIEW的数据流有点类似于C语言的值传递过程。 1.3.1 VI的层次结构 VI是Virtual Instruments的缩写,它类似于C语言中的函数。在C语言中函数可以完成独立的、特殊的功能。函数可以被上一级的函数调用,被调用的函数称子函数。LabVIEW也是类似的,如果一个VI被上一级VI调用,被调用的VI称为子VI,这是基本的模块式编程方法。LabVIEW的“查看”菜单中提供了一个非常有用的功能——VI层次结构。 VI层次结构有自顶向下和自左至右两种不同的显示方式。图1-22所示的是典型的树型结构。根部称做应用程序实例,与之紧密连接的是顶层VI。这是显示给用户的交互GUI,顶层VI调用了6个子VI,双击任何一个VI图标,可以直接打开子VI。顶层VI类似于C语言的main函数,这是应用程序的入口点。从VI名称上看,顶层VI和一般的VI命名无任何区别。这是一个不同于其他编程语言的一个显著特点。也就是说,任何一个VI,既可以作为顶层VI,又可以作为子VI。前面已经知道VI是由前面板和程序框图组成的,而且可以单独运行。但是如果把它作为子 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 19 LabVIEW VI,则仅有前面板和程序框图是不够的,因为一般上一级函数都需要向子函数传递参数,然后由子函数返回处理结果,这种传递参数与返回结果的功能在VI中是通过连线板来实现的。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 20 第章打开LabVIEW编程之门图1-22 VI的层次结构 VI还有一个重要的组成部分——图标。在上一级的程序框图中,子VI是以图标的方式显示的。在图1-22中,Test0、Test1、Test2、Test3就是图标代表的VI。完整的VI由前面板、程序框图、连接板和图标组成。下面通过创建一个计算二次函数的子VI,来介绍建立VI的完整过程。 2已知二次函数Y=AX+BX+C,其中Y作为计算结果应该是输出,而A、B、C、X是作为参数输入的。因此建立的VI应该包括X、A、B、C四个输入控件,一个显示结果Y的显示控件。前面板与程序框图,如图1-23所示。图1-23 二次函数子VI 创建前面板和程序框图后,右击前面板中右上角的图标,在快捷菜单中选择“显示连线板”项。利用工具选板中的连线工具,单击连线板中的端子和前面板中的控件。这样就确立了前面板控件与连线板的一一对应关系,相当于C语言中建立形式参数的过程。双击图标,即可启动图标编辑器。在图标编辑器中,修改VI图标。图标编辑器与常规的图标编辑方式基本相同,也可以直接选择外部图标文件。我们曾经创建过计算Y=KX+B的VI,严格地说它还不能算是子VI,原因是我们并没有分配连接板端子和制作相应的图标。而图1-23已经是一个完整的子VI了,它包括了前面板、程序框图、连接板和图标四个要素。 LabVIEW的子VI可以单独测试,它与常规编程语言相比,具有极大的优势。常规语言的函数测试是非常麻烦的,需要专门做一个显示界面来显示测试结果,或者用打印语句输出中间运行结果和运行过程。而LabVIEW的VI是一个非常强大的模块式结构,每个VI模块都可以单独运行,模块之间不需要紧密的数据连接,非常有利于数据结构的封装。 VI是通过连线板实现参数的输入和输出的。连线板位于前面板和程序框图的右上角。根据 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 21 LabVIEW LabVIEW数据流动的特点,左侧作为输入,右侧作为输出,有利于连线。连线板和VI图标可以通过快捷菜单相互切换,显示连线板后,通过连线工具,分别单击连线板中的端子和控件,就建立了控件和连线板的一一对应关系。 VI图标的制作比较烦琐,在图标中直接用文字来说明则相对简单。另外,也可以直接拖动一个外部图标到VI图标窗口,将它作为模板并做简单的修改,以满足自己特殊的需要。编辑完VI,保存,文件的扩展名自动命名为VI。 1.3.2 调用子VI 在上一节中,我们创建了一个完整的子VI。它包括前面板、程序框图、连接板和图标四个组成要素,可以完成一个二次函数的计算功能。 LabVIEW程序具有典型的层次结构,VI之间的相互调用形成一个完整的程序。在一个VI中调用另一个VI,有如下几种方法。 , 在函数选板中选择“VI”选项,弹出VI选择对话框。它类似于通用文件对话框,用于选择合适的VI。 , 找到相应的VI文件,直接拖动到程序框图窗口。 , 如果需要调用的VI处于打开状态,直接将子VI在前面板或程序框图的图标拖动到程序框图,如图1-24所示。 , 如果建立了项目文件,直接拖动项目文件中的VI,如图1-25所示。图1-24 直接拖动打开的子VI的图1-25 拖动项目文件中子VI的前面板或程序框图图标文件图标到程序框图 1.3.3 VI的属性设置对象是个虚拟的综合的概念。前面板和程序框图本身就可以称为前面板对象和程序框图对象,输入控件、显示控件和装饰控件也是对象,包括接线端子和连线板也都可以称做对象。对于输入控件和显示控件可以通过快捷菜单弹出属性对话框,然后在对话框上设置控件对象的各种属性。VI也是对象,同样具有各种属性,在菜单栏中,选择“文件”,“VI属性”,或者使用快捷键Ctrl+I,可以弹出“VI属性”对话框,如图1-26所示。使用快捷键Ctrl+I可以打开“VI属性”对话框,设置VI的各种属性。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 22 第章打开LabVIEW编程之门 “VI属性”对话框中包含VI的大量信息。有些属于查询信息,处于只读状态,不能更改。有些属于可设置的属性,比如VI的外观、位置等。如图1-26所示,VI属性包括以下几个分页。图1-26 “VI属性”对话框 1,常规 “常规”页面提供了几个重要的信息,包括VI文件名、文件存储的实际位置、当前修订版本号和VI图标信息。在“常规”页面中,还可以更改VI图标。当然如果VI已经打开,则可以在其中直接修改。 “常规”页面中一个重要的功能是设置版本修改信息。每次对VI进行重大修改,都可以添加说明信息,比如修改原因、增加的功能等。单击“重置”按钮,可以将版本号重置为0。通过“VI属性”对话框可以查看VI的实际存储位置。 2,内存使用程序的优劣在很大程度上取决于内存的使用情况,在“VI属性”对话框的“内存使用”页面上,可以查看VI当前占用内存的情况和VI占用硬盘空间的大小。 VI占用的内存空间分为前面板对象、程序框图对象、代码空间、数据空间四部分。在“VI属性”对话框上,可以查看内存使用情况和VI占用的硬盘空间大小。 3,说明信息类似于控件对象的说明。其他VI调用这个VI时,在即时帮助窗口显示该说明。说明信息既可以存储于VI本身,也可以存储于帮助文件中。 4,修订历史设置提示输入修订信息的触发条件,包括每次保存VI时添加注释、关闭VI时提示添加注释、保存VI时提示输入注释、记录由LabVIEW生成的注释。 5,编辑器选项这个页面上可以设置VI的前面板和程序框图的网格线的大小。在菜单栏,选择“工具”,“选项”,在打开的对话框上也有网格线的设置选项。不同的是这个对话框中设置的是LabVIEW的基本工作环境,对所有后来创建的VI都起作用,而在“编辑器选项”中的修改只是对该VI起作用。 “编辑器选项”页面中还可以设置自动创建控件时控件的样式,比如通过函数接线端子自动创建。控件样式可以选择新式、经典、系统三种样式。 6,保护 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 23 LabVIEW 控件对象可以通过工具栏锁定,防止用户非法编辑控件对象。“保护”页面中也可以设置锁定选项,以防止未经授权而更改VI,不过此时锁定的是整个前面板和隐藏的程序框图。如果想查看程序框图或者更改前面板,必须通过“保护”属性页解除锁定。更严格的锁定方式是用密码锁定。我们可以设置密码,没有密码的用户是无法打开VI程序框图的。这样既实现了前面板的锁定,又保护了源代码。不过需要注意的是必须精心设计密码,一旦自己忘记了密码,是没有任何方法解锁的。设置VI密码,可以防止其他人员查看程序框图或者修改前面板。 7,窗口外观在这里可以选择VI的几种外观方式。当然通过属性节点也可以设置外观方式。窗口外观有顶层VI、对话框、默认、自定义四种方式,它们的区别在于是否显示主菜单,是否显示工具栏,以及是否显示窗口最大、最小、关闭按钮等。 8,窗口大小 “窗口大小”页面用来设置前面板的最小尺寸,包括宽度和高度,单位是像素点。VI的前面板中没有直接显示出面板的大小尺寸,可以通过“窗口大小”属性页间接查看前面板的尺寸。当单击“设置为当前前面板大小”按钮后,“宽度”框和“高度”框显示当前前面板的宽度和高度,并把当前宽度和高度作为最小宽度和高度。设置最小宽度和高度后,如果缩小前面板,最小只能达到设定的最小尺寸,扩大则不受影响。另外,也可以直接通过输入宽度和高度数值的方法,直接定义VI前面板的最小尺寸。如果当前面板的尺寸小于设定尺寸,LabVIEW将自动调整前面板到设定的最小尺寸。利用这个方法可以精确设置前面板的尺寸,如图1-27所示。图1-27 “窗口大小”属性页利用设定前面板最小尺寸的方法,可以间接设定前面板的精确尺寸。在VI“窗口大小”属性页上,设定“使用不同分辨率显示器时保持窗口比例”,可以使前面板中的对象按比例适应各种显示器。在该属性页上,还可以设定前面板上的对象与前面板成比例缩放。 9,窗口运行时位置用来设置VI运行时前面板相对于桌面的位置和大小。如果设置为不变,就可以保持VI窗口原来的位置。也可以居中显示、最大化显示、最小化显示,或者采用自定义方式。若采用自定义方式,可以根据需要,自由设定运行时前面板的位置和大小。 10,执行 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 24 第章打开LabVIEW编程之门 “执行”页面如图1-28所示,其中的“标准优先级”和“首选执行系统”比较复杂,一般不需要设置。下面分别介绍其他的选项。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 25 LabVIEW 图1-28 “VI 属性”对话框之“执行”属性页 ,1,允许调试这个属性页上,“允许调试”复选框默认是勾选的。在允许调试的情况下,允许进行单步跟踪、设置断点、调用某个子VI时暂停程序、高亮显示程序运行过程等操作。 ,2,重入执行 “重入执行”复选框,默认没有勾选。由于LabVIEW是支持多线程的,所以两个线程同时调用同一子VI时,需要让先满足数据流条件的子VI首先得到调用权,另外一个线程必须暂时等待,等到上一个调用线程结束调用时,才能得到调用的控制权。简单地说,在不允许重入执行的情况下,任意时刻只能有一个线程可以运行子VI。打开“重入执行”功能,则每个线程运行的是这个子VI备份,具有单独的前面板、程序框图空间和单独的数据空间、代码空间。LabVIEW的很多内部函数节点都是可重入的。加、减、乘、除等基本运算函数,如果不允许重入,程序的运行效率会非常低。 ,3,启动自动错误处理 “启动自动错误处理”复选框,默认是勾选的。这里所要处理的是程序运行过程中发生的错误,而不是指VI本身的错误。当VI本身存在类似于常规语言的语法错误,比如函数节点未连线,,编辑的过程中LabVIEW会提示错误,指出VI无法运行,然后弹出对话框指明错误之所在。另外,在运行过程中可能发生一些不是很重要的运行错误,比如打开一个根本不存在的文件。如果选中“启动自动错误处理”复选框,那么发生运行错误时,就会自动弹出错误对话框。这在实际应用中会带来一些不必要的麻烦。比如一个无人值守的监控程序,如果发生非特别重大错误,弹出对话框后会停止程序的运行,直到有人取消错误对话框,这显然是不能允许的。这种情况下,可以取消“启动自动错误处理”复选框的选择,由程序本身设置错误捕捉陷阱,然后根据错误的类型、性质和严重程度,采取相应的处理措施。 ,4,打开时运行 “打开时运行”复选框,默认不勾选。这里的打开是指在LabVIEW菜单栏中,选择“文件”,“打开”项来打开,或者是在计算机中直接双击VI文件名打开。不勾选“打开时运行”复选框,则以编辑方式打开文件,勾选这个复选框,则打开后直接运行文件。 ,5,调用时挂起 “调用时挂起”复选框,默认是不勾选的。这个选项主要是在程序调试时使用的。当勾选后,程序调用到这个VI时,暂时停止程序。这时可以通过探针等调试工具观察VI的运行情况。 ,6,调用时清空显示控件 “调用时清空显示控件”复选框,默认情况下是不勾选的。显示控件当前显示的值完全取决于它的接线端子当前数据的流动情况。在某些情况下,数据根据条件可能不会流入到显示控件,这and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 26 第章打开LabVIEW编程之门时可以选择“调用时清空显示控件”复选框。另外,这里的所谓“清空”,并非不显示任何值,而是显示显示控件的默认值。通过“VI属性”对话框的“执行”属性页设定“调用时清空显示控件”,显示控件将显示默认值。 11,打印选项常规编程语言都提供了代码打印功能,而LabVIEW的代码实际就是程序框图,它能打印出来吗,一个条件选择结构可能包括很多条件分支,而同一时刻屏幕上只能显示其中一种,能打印出全部吗, LabVIEW不但可以打印,还可以对不同的VI进行单独的设置,单独的打印设置随着VI一起存储。如图1-29所示,在“打印选项”页面上,可以选择是否打印页眉,是否对前面板加边框,是否缩放前面板匹配打印页面,是否缩放程序框图匹配打印页面,还可以自定义上、下、左、右的页边距。图1-29 “打印选项”页面 “每次VI执行结束时自动打印前面板”复选框默认不勾选。这项设置在特定情况下非常有用。例如,我们要制作一个票据打印系统时,首先可以制作一个标准的前面板,其中包括必须输入的数据和相关计算的结果显示,然后勾选这个选项,那么当VI调用结束,系统就会自动调用打印机打印结果。在工业控制中,可以自动打印报警信息或者程序中间运行结果。 VI属性非常多,这里无法一一介绍。要了解这些属性的作用,需要在编程时仔细体会。通过以上的讨论,我们已经学会了如何创建、编辑、调用VI,以及如何设置VI的属性。我们知道,VI的前面板是由各种控件组成的,所以必须充分了解各种控件的使用方法,这是LabVIEW编程的基础,也是下一节要介绍的内容。 1.4 基本控件及其使用方法我们必须首先了解的基本控件包括基本数值控件、布尔控件、数组控件、簇控件、波形图表控件和波形图控件。之所以首先要了解这些基本控件,是因为它们是最常用的,是构成一个VI的基本控件对象。VI就是程序,程序是离不开数据和运行结构的。 1.4.1 基本数值控件 LabVIEW是通过控件选板选择控件对象的。控件选板包含了大量的LabVIEW控件,按照控件能代表的数据类型,比如数值型数据、布尔型数据、字符串和路径数据等,分成不同的类别。每and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 27 LabVIEW 个类别中的控件所包含的数据类型是相同的或者近似的,同类别控件又分为不同外观形式的输入控件和显示控件。 1,打开和固定控件选板打开控件选板的最基本方式当然是使用菜单,控件选板、函数选板都位于“查看”菜单中。不过最方便的方法是右键单击前面板任意位置,弹出控件选板。选择完成后,弹出的控件选板会自动关闭。单击控件选板左上角的图钉按钮,可以使选中的控件类别固定显示,始终处于打开状态。这种情况适用于创建多个类型相似,但是外观不同的控件。用图钉按钮固定显示,是LabVIEW常用基本操作,函数面板中也有作用相同的图钉按钮。如图1-30所示,这里演示了图钉按钮的使用方法。数值控件有多种显示方式,但是它们都有一个共同的特点——控件包含的数据类型都是数值型的。数值输入控件是最基本的数值控件,其他不同外观的数值型控件都是以它为基础的。LabVIEW的控件是典型的对象继承结构,数值输入控件是其他数值型控件的基类。 2,数值控件的组成和显示方式数值输入控件对象由一些基本对象元素组成的,这些元素包括增量按钮、减量按钮、数字文本框、标签、图1-30 使用图钉按钮标题、单位标签和基数等。基数指的是进制形式,可以是十进制、十六进制、八进制、二进制。基数不同,不过是数值的表现形式不同,它所代表的值是相同的。图1-31说明了数值输入控件的基本对象元素以及进制、单位的不同表现形式。数值输入控件的基数默认是不显示的,可以在它的快捷菜单上选择“显示”,“基数”项来确定是否显示。常规语言中对一个数用不同的进制显示需要由编程实现,非常复杂,而在LabVIEW中只需选择相应的进制。这充分说明了LabVIEW的确是工程师的语言,直观、方便又快捷。图1-31 数值控件的组成和进制转换如果数值控件的基数处于显示状态,单击基数标记,数值左侧,,可以自由选择十进制、十六进制、八进制、二进制和SI符号。如果是整型数,那么这些数值都可以选择,如果是双精度数等,则只能选择十进制和SI符号。另外,LabVIEW可以自动判断哪些是可以显示其他进制的,哪 3些是不能显示的。选择SI符号,会以字母的形式显示比较大或者非常小的数值。例如,10用K 69-3-6-9表示,10用M表示,10用G表示,10用m表示,10用u表示,10用n表示等。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 28 第章打开LabVIEW编程之门在数值控件的快捷菜单上,可以选择是否显示基数。通过单击控件上的基数, 可以选择十进制,二进制、八进制、十六进制和SI显示。很大和很小的数值适合用SI符号表示。数值控件不仅可以实现数制的自由转换,还可以携带物理单位。图1-31中,右面的两个数据是包括单位的。它们采用克隆方式复制,所以数值相同。如果把km改成m,数值将自动由1变成了1000,自动实现了不同物理单位的转换。 LabVIEW数值输入控件的单位标签默认是不显示的,但是可以在它的快捷菜单上选择“显示”,“单位标签”项,来确定是否显示。适当地运用数值控件的单位标签,可以自动进行单位转换。单位转换的功能是非常重要的。因为在实际应用过程中,经常会遇到单位转换的问题。只要适当选取单位标签,LabVIEW会自动地为我们完成单位转换的工作。另外,LabVIEW不仅可以对相同单位类型进行转换,比如长度单位,,还可以通过运算自动处理组合单位,如图1-32所示,长度相乘,自动生成面积单位。图1-32 长度的乘积是面积,LabVIEW自动处理单位 3,数值控件的属性在快捷菜单上,选择“属性”项,即可打开属性对话框。属性对话框由许多属性页组成,涵盖了大量的控件属性设置信息,其使用极其频繁,必须详细了解。不同的控件属性对话框的内容是不同的,其中数值型属性对话框最为复杂。如图1-33所示,这里以量表控件的属性对话框为例,说明一下数值型控件属性的用法。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 29 LabVIEW 图1-33 量表控件的属性对话框如图1-33所示,数值型控件的属性对话框由多个页面组成。标签、标题等通用属性我们已经介绍过,下面重点关注数值控件的专用属性。 ,1,外观 “外观”选项卡的下半部分是专用属性选项,不同类型的控件这部分选项有很大不同。在量表控件的属性中,通过“添加”按钮,可以增加指针,默认情况下增加一个指针。量表、旋钮、滑动杆控件是继承于基本数值控件的,它内部本身就包含一个基本的数值控件。默认情况下基本数值控件是隐藏的,可选择显示数值控件来打开它,并选择显示图1-34 修改后量表控件的显示效果基数,修改后效果如图1-34所示。对于可以用鼠标拖动的数值型控件,还有三个重要的选择项。 , 显示当前值提示框。默认情况下,运行时用鼠标拖动旋钮或者滑动杆,会自动出现了一个黄色的数字框,提示当前位置的值。 , 锁定在最大最小之间。如果取消“锁定最大最小之间”复选框的选择,则指针或者旋钮随着鼠标的移动自由跟随移动。当达到最大值继续移动时,马上会回到最小值。这种情况在实际应用中有时会非常危险。例如,通过旋钮控制重物的高度,如果不锁定在最大最小之间,当鼠标拖动超过最大时,则会从最高点突然降落到最低点,造成事故。如果勾选了“锁定到最大最小之间”复选框,则当鼠标拖动数值到最大和最小区域之外时,拖动操作将无效,避免了上述情况的发生。 , 跟随鼠标。旋钮类型控件还可以选择是否开启鼠标跟随功能。未选择“跟随鼠标”复选框时, 只能通过拖动改变控件的值,选择“跟随鼠标”复选框后,单击旋钮或量表的任意位置,则旋钮或者指针自动指向到鼠标位置,控件的值随之自动改变。使用旋转型数值控件要特别注意是否选择“锁定在最大最小之间”复选框。 ,2,数据类型对“数据类型”属性页的设置非常简单,主要是选择控件所代表的数据类型,比如各种整型数、浮点数等。对于定点数,“数据类型”属性页提供了比较详细的设置。改变数据类型一般通过快捷菜单中“表示法”项来选择,比使用“数据类型”页来选择要方便得多。 ,3,数据输入 “数据输入”属性页如图1-35所示。默认情况下“使用默认界限”复选框是勾选的。LabVIEW是面向工程应用的软件,因此,对输入控件要求很高,必须保证用户的输入是有效的和合理的。“数据输入”属性页用来设置输入的有效范围以及超出界限后的处理方法。如图1-35所示,“数据输入”属性页主要用于设置数据的输入范围,包括如下内容。 , “最小值”和“最大值”参数,用于设置数值的输入范围。对于图形用户接口界面来说,对数值设定输入范围是非常重要的。根据实际需要, 程序设计者有必要限定输入的具体范围。例如,如果要设计一个输入年龄的输入控件,首先要通过“数据类型”属性页或控件快捷菜单,and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 图1-35 “数据输入”属性页 30 第章打开LabVIEW编程之门选择合适的数据类型。比较合理的选择是U8数据类型,它只占用1个字节,默认最大值是255,最小值是0。然后限定合适的输入范围,比如最小值是0,最大值是150。无论如何,我们不能依赖用户来输入合理数据。在程序设计时就应该充分考虑各种情况,要由程序保证数据的输入是合理的、有效的。需要适当地设置数据的合理输入范围,保证用户输入的是有效数据。输入范围的设置对GUI起作用,对不显示前面板的子VI调用无效。 , “增量”参数用于设置数值型控件中单击“增量”、“减量”按钮时,数值变化的最小量,一般使用默认设置。 , 在“超出界限的值的响应”区域可以对于超出范围的数据,设置“忽略”或者“强制”的处理方式。采用“忽略”方式,超出设定范围的数据依然有效。选择“强制”方式,则自动把大于最大值的输入强制转化成最大值,自动把小于最小值的输入值转化成最小值。对于数值控件的多位数输入,用光标定位,比如光标定位于百位,单击增减量按钮,则数值整百增加或者减少,光标定位于千位,单击增减量按钮,则数值整千增加或者减少。光标定位数字的位,增减量按钮可以按照位所代表的数值快速增加或者减少。 ,4,显示格式如图1-36所示,“显示格式”选项卡包含了丰富的格式信息,包括选择计数法、选择进制、时间格式等,还有很多特殊的用法,包括是否隐藏无效0,是否使用最小域宽等。选择最小域宽,比如设置为6位,当数值不满6位时,不足位用空格或者0填充。选择空格时,可以选择左侧填充空格或者右侧填充空格。如图1-37所示,在属性页左下方,选中“高级编辑模式”选项,即可自定义显示格式,包括多行显示,不同进制显示等,功能非常强大。例如,选择“数值格式代码”项,然后在下方选择“浮点表示”项,格式字符串如图1-38左图所示。最后得到的效果,如图1-38右图所示。图1-36 “显示格式”属性页图1-37 显示格式之高级编辑图1-38 高级编辑后的效果数值控件的高级显示格式中,格式字符串的运用非常关键,数字的格式字符串如表1-2所示。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 31 LabVIEW 表1-2 整数和浮点数格式字符串整数浮点数 x,十六进制整数,例如,B8, f,带小数格式的浮点数,例如,12.345, o,八进制整数,例如,701, e,科学计数法表示的浮点数,例如,1.234E1, g,根据数字的指数,LabVIEW使用f或e。若指数大于–4或小于指定b,二进制整数,例如,1011, 的精度,LabVIEW使用f。若指数小于–4或大于指定的精度,LabVIEW 使用e d,带符号的十进制整数 p,以SI符号表示的浮点数 u,不带符号的十进制整数格式字符串以“%”开始,按快捷键Shift+Enter可以在编辑字符串的时候换行。 ,5,说明信息 “说明信息”属性页包括“说明”和“提示框”。控件的说明是出现在即时帮助窗口中的,使用快捷键Ctrl+H可以随时打开和关闭帮助窗口。当光标在控件上停留时,则显示提示框,如图1-39所示。在“说明信息”属性页的说明框和提示框中,可以编辑和添加控件的详细说明和简要提示。通过标注“”和“”,还可以使这段文字加粗显示。“说明”中的信息可以写详细些,但是“提示框”中的文字要简明、直观。说明和提示框的具体用法如图1-40所示,特别要注意加粗文字的方法。图1-39 即时帮助和运行时控件提示条图1-40 控件说明和提示框控件在编辑状态下是不显示提示框的,只有运行时才能显示。即时帮助窗口下方有“显示完整连线端及路径”、“锁定帮助”和“详细帮助”三个按钮。其中第一个非常实用,用来在即时帮助窗口显示VI在硬盘中的绝对路径。 ,6,快捷键在“快捷键”属性页上,可以为显示给用户的GUI上的控件设置快捷键。不显示给用户的子VI,则不需要配置快捷键。不同类型的控件,“快捷键”属性页上的选项是不同的。 LabVIEW会自动显示控件可以配置快捷键的部分,比如数值型控件,可以配置为选中、增量按钮和减量按钮,其中增量按钮和减量按钮还可以进一步配置是否选中。如果配置选中,则使用快捷键后,不但控件的值发生变换,同时数值控件还处于选中状态,具有焦点。配置快捷键时既可以配置单独的键,也可以用Ctrl或者Shift配置成组合键。如果控件处于隐藏、禁用或者禁用并发灰状态,则快捷键不起作用。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 32 第章打开LabVIEW编程之门有的程序,比如一个监控程序,,如果不希望无关人员停止它,我们可以选择将“停止”按钮设置为禁止、禁止并发灰或隐藏的方式。但是隐藏了“停止”按钮,有授权的人也将无法停止程序。这种情况下,可以将“停止”按钮移动到显示界面之外,并为它配置一个切换的快捷键。然后我们就可以通过快捷键停止程序运行,而其他不知道快捷键的人员将无法停止程序。另外,“快捷键”属性页中,还可以设置控件是否忽略Tab键。通常情况下,可以用Tab键切换控件,被切换的控件具有焦点。如果为控件设置“忽略Tab键”功能,则按Tab键时,将越过这个控件选择下一个。 ,7,文本标签 “文本标签”属性页如图1-41所示,设置好文本标签的效果图如图1-42所示。很多数值控件的快捷菜单中,都有“文本标签”选项,比如滑动杆、旋钮、转盘和量表等。它们不仅可以显示连续数字,也可以通过文本标签功能变成档位开关。图1-41 “文本标签”属性页图1-42 文本标签效果图 1.4.2 基本布尔控件布尔控件属于常用控件,其使用极其频繁。与常规语言的布尔型控件不同,LabVIEW提供了大量的、功能各异的布尔型控件,极大地方便了用户。不仅如此,LabVIEW在DSC组件中也提供了大量的布尔型控件,比如管路、阀门等。开关型控件在工业领域是非常重要的。比如各类开关、按钮、继电器等,从物理描述上来看都是布尔型,只有“开”和“关”两种状态。在编程语言中一般使用真和假描述,这样更具有普遍性。 1,布尔型控件 LabVIEW的布尔数据类型占用一个字节,而不是位。一个字节从二进制的角度上看是由8个位组成的,一个字节实际上可以表示8个真假状态。目前,几乎所有的编程语言都采用整数来表示布尔量。虽然字节相对于位来说,占用的空间比较大,但是它是各种编程语言支持的基本数据类型,运算速度很快。只有在单片机编程中,由于RAM空间极其有限,才采用位表示布尔型数据。 LabVIEW的布尔型数据占用一个字节。 LabVIEW的控件分成三大类——现代型控件、古典型控件和系统控件。现代型控件具有立体外观,也称做三维控件。LabVIEW的古典型布尔控件的外观某些时候更类似于真实的开关、按钮等。古典布尔控件主要用在早期版本的LabVIEW中,不过现在仍然有很多人继续使用。系统型控件与操作系统本身用的控件是类似的,在涉及软件系统配置对话框中,经常使用系统型控件。 LabVIEW布尔型控件从名称上看分成两类,按钮布尔控件和开关布尔控件。按钮和开关虽然都是布尔型控件,但是它们的物理意义是有区别的。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 33 LabVIEW 真实的按钮按下时改变原来的状态,释放后自动恢复到原来的状态。原来的状态是接通还是断开,取决接线方式,因此有常开按钮和常闭按钮。开关则不同,改变状态后,开关自己保持在一个稳定状态,直到下一次改变为止。比如,计算机机箱上的是启动按钮而不是启动开关,是因为按钮内部有个弹簧,当手离开后,弹簧使按钮自动复位,而灯的开关则完全不同,当打开开关后,它会自动保持在打开的状态。 LabVIEW布尔型控件分成按钮型和开关型,应根据需要选择按钮或者开关。虽然LabVIEW的布尔型控件分成按钮型和开关型两种,但是LabVIEW内部并没有区分按钮型和开关型。从编程的角度看它们是完全相同的,只是默认的操作方式不同。编辑GUI时还是要根据需要,选择合适的按钮或者开关,以免造成用户误解。 2,LabVIEW布尔控件的机械动作属性所有的控件属性都是通过快捷菜单和属性对话框进行设置的。布尔控件的标签、标题、可见性、是否开启、说明、快捷键配置等通用属性,与数值型控件非常类似。除了上述的通用属性外,LabVIEW的布尔型控件还有一个特别的属性——机械动作属性。机械动作属性是布尔型控件特有的,也是常规编程语言中不存在的属性。布尔控件“值改变”的瞬间是非常重要的,在现实世界里也存在这种现象。比如我们有一个手持的计数器,每按一下按钮,需要增加一个计数。这时我们就要考虑机械动作的问题。如果按钮一旦按下就开始计数,由于仪器内部反应非常快,当我们按下和释放之前,内部可能产生多次计数,这显然是不合理的。正确的做法是在按钮抬起时计数,这样就可以按一下,产生一次计数。在各类机械动作中,该类动作称做“释放时转换”。LabVIEW布尔控件的机械动作共分成六种,根本区别在于转换生效的瞬间和图1-43 布尔控件的机械动作 LabVIEW读取控件的时刻,如图1-43所示。在属性对话框的“机械动作”属性页中,不但可以选择6种不同的机械动作,还可以直接预览实际效果。如果对机械动作本身非常熟悉,直接在快捷菜单中选择机械动作比较快捷。如图1-43所示,总计6种机械动作,它们的图标非常形象,最上边的M,mouse,表示操作控件时鼠标的动作,V,value,表示控件输出值,RD,read,表示VI读取控件的时刻。下面按照图1-43中从左至右的顺序,介绍这6种机械动作。 ,1,单击时转换这种机械动作相当于机械开关。鼠标单击后,立即改变状态,并保持改变的状态,改变的时刻是鼠标单击的时刻。再次单击后,恢复原来状态,与VI是否读取控件无关。 ,2,释放时转换当鼠标按键释放后,立即改变状态。改变的时刻是鼠标按键释放的时刻。再次单击并释放鼠标按键时,恢复原来状态,与VI是否读取控件无关。 ,3,单击时转换保持到鼠标释放这种机械动作相当于机械按钮。鼠标单击时控件状态立即改变,鼠标按键释放后立即恢复,保持时间取决于单击和释放之间的时间间隔。 ,4,单击时触发这种机械动作中,鼠标单击控件后,立即改变状态。何时恢复原来状态,取决于VI何时在单击后读取控件,与鼠标按键何时释放无关。如果在鼠标按键释放之前读取控件,按下的鼠标不再and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 34 第章打开LabVIEW编程之门继续起作用,控件的值已经恢复到原来状态。如果在VI读取控件之前释放鼠标按键,改变的状态保持不变,直至VI读取。简而言之,改变的时刻等于鼠标按下的时刻,保持的时间取决于VI何时读取。 ,5,释放时触发这种机械动作同“单击时触发”类似,差别在于改变的时刻是鼠标按键释放的时刻,何时恢复取决于VI何时读取控件。 ,6,保持触发直至鼠标释放这种机械动作中,鼠标按键按下时立即触发,改变控件值。鼠标按键释放或者VI读取,这两个条件中任何一个满足,立即恢复原来状态。到底是鼠标释放还是VI读取触发的,取决于它们发生的先后次序。布尔控件还具有一个独特的属性——布尔文本属性。布尔文本用文字的方式表示出当前布尔控件的状态,即真或假。很多布尔控件从颜色上可以区分真、假状态,有些则不然。布尔输入型控件向用户明确表明当前状态非常重要。通过显示布尔文本,用户可以准确理解控件的当前状态,从而选择对应的操作。布尔文本的目的是显示“真/假”两种状态,但是在实际应用中,可以有多种描述方法,比如ON/OFF、开/关、抬起/落下、升/降等。可以自由选择符合实际意义的文本描述,不过要特别注意和真/假的对应关系。布尔控件选板中,还存在确定、取消和停止三个常用的按钮。这三个按钮的属性基本相同。因为极其常用,所以单独列出,免掉了修改按钮外观和说明的麻烦。 3,个性化布尔控件我们前面已经提到过控件的自定义问题。控件自定义功能的使用极其广泛,尤其是布尔型控件。在GUI制作中,经常需要独具特色的按钮或者开关,来模拟外部真实开关和按钮。这就需要我们根据要求自定义布尔控件。LabVIEW提供了强大的控件自定义功能,可以非常方便地制作特色控件。先看一下一些特色按钮和指示灯的效果图,如图 1-44所示。图1-44中的自定义按钮是都过控件自定义功能创建的。自定义布尔控件最耗时的操作是图片的制作, 一般可以通过专业图片处理软件来完成。有了数码相机之后,图片的制作相对容易多了,可以把真实的按钮和开关拍摄下来作为素材,再通过专业图片处理软件,做简单的图1-44 自定义按钮效果图处理就可以使用了。一般布尔控件需要4张图片,分别为,? 布尔控件为FALSE的图片,? 布尔控件为TRUE的图片,?布尔控件从TRUE转换成FALSE触发瞬间的图片,? 布尔控件从FALSE转换成TRUE的图片。通常情况下,只需准备表示TRUE和FALSE的两幅图片,?、? 使用相同图片,?、? 使用相同图片。下面以自定义按钮为例说明一下自定义按钮布尔控件的详细过程。准备图片素材。启动控件编辑器。可以通过两种方式启动控件编辑器,一种方法是在菜单中选择“文件” ,“新建”,“其他”,“自定义控件”项,另一种方法是在前面板上布尔控件的快捷菜单中, 选择“高级”,“自定义”项。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 35 LabVIEW 在工具栏的控件类型下拉列表中选择输入控件,其他两项分别是自定义类型和严格自定义类型,通过工具条中的切换按钮切换到编辑模式,删除三维边框。在现代控件中,为体现三维效果,一般的控件都包括一个边框对象作为装饰,不需要时可以删除这个装饰对象。然后导入图片,可以通过剪切板导入图片,也可以直接从文件中导入。右击控件, 通过快捷菜单,选择“从文件中导入图片”,此时导入的是FALSE状态图片,然后依次导入四幅图片,其中,1、3为代表FALSE的图片,2、4为代表TRUE的图片。建立图标,存储文件。类似于一般VI的制作,自定义控件存储在一个单独的文件中, 具有自己的文件名和图标。使用自定义控件时,通过控件选板中的“选择控件”项,在文件对话框中找到对应的后缀为CTL文件,打开后,即在VI的前面板中创建了这个控件, 也可以通过“我的电脑”,找到对应的文件,直接拖动到VI的前面板。 4,单选按钮单选按钮为常见控件,LabVIEW把单选按钮归类在布尔控件的类别中。单选按钮本质上是枚举型控件,属于“多选一”方式,而布尔控件本身只有真/假两种状态。单选按钮是由多个布尔控件组合而成的,通过替换操作可以选择各种LabVIEW的布尔控件,如图1-45所示。图1-45 通过替换操作,选择单选按钮中的布尔控件默认的单选按钮只包含两个,在快捷菜单上选择“添加单选按钮”项,可以增加按钮的数量。单选按钮允许使用不同外观,但是通常情况下使用的都是相同类型的按钮。首先用替换操作选择所需的外观的按钮,隐藏不需要显示的项目,比如标题、标签、布尔文本等。然后拉大它的边框,选择要复制的按钮,采用按住Ctrl键+拖动的方式克隆按钮。单选按钮的快捷菜单中,还有一个重要的选项——允许不选。我们不需要选择单选按钮中的任何按钮的时候,就可以使用“允许不选”功能。 1.4.3 控件的通用编辑方法控件的大部分属性都是通过快捷菜单设置的。控件由基本对象元素构成,比如标签和标题属于文本对象,各类装饰属于装饰对象。LabVIEW允许改变文本的字体、字号、粗细、前景颜色和背景颜色等。上述所有操作属于通用编辑操作,对于前面板上的控件和程序框图上的接线端子等,都可以使用。控件的创建、复制、改变大小、对齐、排序等,前面已经提到了,也属于通用编辑部分。 1,文本的编辑方法工具选板中专门设置有一个编辑文本的按钮,如果工具选板未出现,可以在菜单栏上选择“查看”,“工具选板”项,显示工具选板。按下Shift键,然后右击前面板或程序框图,显示临时工具选板。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 36 第章打开LabVIEW编程之门按下Shift键,然后右击前面板或程序框图,可以显示临时工具选板。选取文本,通过选择工具选板中的“编辑文本”按钮,单击要编辑的文本,比如控件标签,则文本自动选中,文字将反白显示。光标定位在单击处,这时可以添加或者替换文字。双击选取整个文本,此时若输入文本,则原文本整体被替换。当工具选板处于自动状态时,双击文字所在区域,将自动选择整个文本。然后单击文字,光标自动定位到单击处。最常见的方式是拖动选择文本,使用光标在文本上画框,可以选取部分或者全部文本。工具选板处于自动状态时,双击文本,即可选取整个文本区域。对于数字控件的数值编辑,既可以用“文本编辑”按钮,也可以用“操作值”按钮。使用光标在文本上画框选中一个或者几个数字位。对数值控件“值”的修改可以通过“操作值”按钮或“文本编辑”按钮来完成。 2,文本的外观设置文本的外观包括字体的选择、大小、样式和颜色,它们都可以在工具栏上进行设置,如图1-46所示。选中文本后,工具栏上将自动显示选中文本的字号和字体。非顶层VI的标签或者标题等,其文本外观可以保持默认设置。GUI窗口的显示为了醒目,可以选择一些特殊的字体、字号和颜色。含有物理单位的标签,则可以用粗体显示名称。单位只要使用无格式字体即可。选中文字后,按组合键“Ctrl,”,即Ctrl键图1-46 工具栏的文本设置按钮与减号键,可缩小字体,按组合键“Ctrl+”可放大字体。文字样式包括无格式、加粗、加下画线,斜体、轮廓线等。文本的颜色也可以在工具栏上设置。如图1-46所示,在下拉列表中选择“颜色配置”项,即可打开颜色对话框,并选择合适的颜色。文字的背景颜色,则可以通过工具选板中的“设置颜色”工具按钮配置。 3,自由标签 LabVIEW的自由标签类似于VB中的Label控件。它显示只读文字信息,通常用于装饰和注释说明,在前面板和程序框图中都可以使用。在系统控件中也有自由标签,它和现代控件选板上的自由标签有所不同。系统控件中标签的背景色和窗体客户区是相同的,而自由标签在前面板中是透明的,在程序框图中是黄色背景。系统标签与自由标签的不同效果,如图1-47所示。创建自由标签同文本编辑一样,都是通过工具选板中的“编辑文本”工具按钮进行的。在工具选板处于自动状态时,在前面板或程序框图的空白处双击,可以创建自由标签。工具选板处于自动状态时,双击前面板或程序框图,将自动创建自由标签。 4,修改颜色 LabVIEW中对对象颜色的修改都是在颜色对话框中进行的,颜色对话框如图1-48所示。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 37 LabVIEW 图1-47 系统标签和自由标签图1-48 颜色对话框颜色对话框上从上到下分为多个部分。 , 顶层的颜色条由白色、黑色和灰色组成,主要用于区域较大部分的调色,比如前面板、装饰。单击右上角的按钮,当按钮显示文字“,”时,表示选择透明色,再次单击该按钮, 按钮显示文字“,”时,表示不使用透明色。 , 第二个颜色条是亚暗色调,适用于中等大小的区域,比如控件等。 , 第三个颜色条是深色调,适用于比较小的区域,比如指示灯、曲线等。深色调是高亮的, 只能用在特别需要引起注意的地方,不可滥用。否则,用户的注意力可能被吸引到无关区域。 , 第四行用户组颜色,设置的是LabVIEW本身对象常用的颜色。使用用户组颜色有利于界面设计的统一和协调。当光标移动到每个小的颜色框按钮时,最下方R、G、B处提示该颜色建议使用的控件,比如指示灯、进度条等。在菜单栏上,选择“工具”,“选项”,“颜色设置”项,在属性页中可以设置用户组的颜色。 , 第五行为历史颜色,记录的是你最近使用的颜色。 , 左下方的是长方形颜色显示效果框。光标在颜色选择框上移动时,选中控件颜色自动跟随其变化。单击右下方的按钮,可以打开系统颜色对话框。控件的很多对象元素都是可以更改颜色的,如果我们希望采用和界面上已有对象同样的颜色,那么可以使用工具选板上的“提取颜色”按钮。该按钮外形似吸管状,单击它,然后在现有对象上提取颜色,即可为其他控件配置相同的颜色。选择工具选板中“配置颜色”工具按钮后,按下Ctrl键,该按钮可以暂时变成提取颜色按钮,获取颜色后,再继续配置颜色。 1.4.4 字符串和路径控件 LabVIEW以字符串输入控件和字符串显示控件的方式,提供了对字符串的支持。在常规语言中,很少有专门的路径类型,路径不过是特殊格式的字符串而已。LabVIEW中,路径是一种专门的数据类型,同时和字符串存在密切的关系,二者之间可以自由转换。在LabVIEW的字符串和路径选板中,还包括组合框控件。组合框提供了预先定义的一组字符串,以供用户选择。 1,字符串控件字符串控件是字符串数据的容器,字符串控件的值属性是字符串。如同其他类型控件一样,LabVIEW的字符串控件也分为输入控件和显示控件。输入控件的值可以由用户通过鼠标或者键盘and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 38 第章打开LabVIEW编程之门来改变,而显示控件则不允许用户直接输入,只能通过数据流的方式,显示字符串信息。 LabVIEW的字符串控件颇有特色,具有4种不同的显示方式,可以通过快捷菜单或者属性对话框设置,如图1-49所示。图1-49 不同显示方式的效果展示 ,1,正常显示以字符的方式显示字符串数据,这是字符串默认的显示方式。对于不可显示的字符,则显示乱码。可显示字符也可称作可打印字符。 2,使用“\”转义显示 , 不可显示的字符以反斜杠加ASCII 十六进制的方式显示。对于回车、换行、空格等特殊字符,则采用反斜杠加特殊字符的方式显示。LabVIEW支持的特殊字符如表1-3所示。表1-3 特殊字符的反斜杠表示。代码十六进制十进制含义 \b 0x08 8 退格符号 \n 0x0A 10 换行符号 \r 0X0D 13 回车符号 \t 0x09 9 制表符号 \s 0x20 32 空格符号 \\ 0x5C 92 “\”符号 \f 0x0C 12 进格符号 \00 -----\FF 8位字符的十六进制值代码中,反斜杠“,”后的特殊字符必须是小写的,而“\ + ASCII HEX”,其中十六进制中的A、B、C、D、E、F必须是大写的。比如,“\02”表示输入STX,“\1B”表示 ESC。 ,3,密码显示选择密码显示方式时,用户输入的字符在输入字符串控件中显示为星号,一般常用于登录对话框。此时输入的真实内容是字符,类似于正常模式,只是显示为星号而已。字符串控件支持复制、粘贴命令,如果在密码显示状态下,选择复制,则复制的是星号,而不是星号代表的字符。 ,4,十六进制显示以十六进制数值方式显示字符串,这种方式在通信和文件操作中,经常会遇到。图1-49展示了不同显示方式下字符串的不同效果。在“\”转义显示方式中,空格和换行是特殊字符,分别为\s 和\n。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 39 LabVIEW 字符串控件通过回车换行,但是字符串内部未包含回车,只有换行符“\n”。 LabVIEW在字符串控件快捷菜单和属性对话框中,还提供了几个非常重要的属性选项,如图1-50所示。图1-50 属性页和快捷菜单 , 限于单行输入选中该项,将只允许输入一行文本,不响应回车换行操作。输入的回车被忽略,因此无法换行。 , 键入时刷新选中该项,控件的值在输入每个字符时将同步刷新。该项默认情况下未选中。未选中时,必须在结束输入时才产生字符串值改变事件。通过单击前面板使字符串控件失去焦点,则LabVIEW将自动确认输入完成。 , 启用自动换行默认情况下,自动换行功能是启用的。这样,当输入到字符串输入控件的行末尾时,将自动转到下一行。需要说明的是这种换行只是显示上的,实际字符串中并没有真正换行。如果不启用自动换行,则输入的字符始终单行显示。在快捷菜单上,选择“显示”,“水平滚动条”项,可以查看不在显示区域的行文本。启用自动换行时,“水平滚动条”项是不允许选择的。结束输入有两种方法。 , 当执行文本输入操作时,工具条最左侧显示“确定输入”按钮,图标为对号。单击“确定输入”按钮后,按钮消失且文本输入被确认。 , 另外一个更方便的方法是单击前面板或前面板上其他控件,使字符串控件失去焦点,则 LabVIEW将自动确认文本输入。 2,组合框控件组合框控件可用来创建一个字符串列表。在前面板上可按次序浏览该列表。组合框控件类似于文本型或菜单型下拉列表控件。但是,组合框控件的值属性包含的是字符串型数据,而下拉列表控件是数值型数据。在组合框控件上打开快捷菜单,选择“编辑项”选项,即可向列表中添加字符串供用户选择。组合框属性对话框的“编辑项”中的字符串顺序,决定了控件中的字符串顺序。默认状态下,组合框控件允许用户输入未在该控件字符串列表中定义的字符串值。在组合框控件上打开快捷菜单,取消“允许未定义字符串项”的勾选,即可禁止用户输入未定义字符串。如果在运行时向组合框控件输入字符串,LabVIEW将即时显示以所输入字母开头的第一个最短的匹配字符串。如果没有匹配的字符串,也不允许输入未定义的字符串值,LabVIEW将不会接收或显示用户输入的字符。在配置组合框控件的字符串列表时,可为每个字符串指定一个自定义值,使前面板组合框控and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 40 第章打开LabVIEW编程之门件中显示的字符串,与程序框图中组合框控件接线端返回的字符串不同。具体方法如下。在组合框控件上打开快捷菜单,选择“编辑项”选项,打开组合框属性对话框。在对话框的“编辑项”选项卡中,取消“值与项值匹配”复选框的勾选。然后在该对话框表格的“值”列中,修改与控件中每个字符串对应的值即可。 3,路径控件路径控件是LabVIEW提供的独特的数据类型,专门用来表示文件或者目录的路径。常规语言一般都是用字符串控件,附加一些特殊的格式来表示路径的。LabVIEW的路径极大地方便了文件和目录的选择操作。与字符串控件不同的是路径控件包括一个浏览按钮。单击浏览按钮,将弹出文件选择对话框。在这里,可以选择相应的文件或者目录的绝对路径。路径控件支持拖动操作,在计算机上找到文件或者文件所在文件夹后,直接拖动文件或文件所在的文件夹到路径控件,则路径控件显示的是被拖动文件或者目录的绝对路径。拖动文件或者文件所在文件夹到路径控件,路径控件将显示它们的绝对路径。路径控件本身比较简单,但是LabVIEW对路径控件的“浏览”按钮专门提供了属性设置,如图1-51所示。 “浏览选项”属性页上包括很多可设置的选项,具体作用如下。 ,1,提示在这里可以输入文件对话框的标题条。如果为空, 文件对话框标题栏显示为“打开”。 ,2,类型标签在这里可以设置文件类型匹配符。比如要选择 Word文档,可以设置“类型标签”为“Word”,在右边设置“类型”为“*.doc”,则在对话框文件类型中将用Word ,*.doc,显示所有doc型文档。 ,3,类型在这里可以设置要选择的文件类型。全部文件图1-51 “浏览”按钮的属性设置 ,*.*,是内部存在的,不需要设置。若选择多种类型, 则用分号隔开,注意不能有空格。例如“*.doc,*.txt”,表示显示所有doc和txt型文件。 ,4,选择模式选择其中的某个单选框,可以设置打开文件或者文件夹,打开现有文件、文件夹、新建文件或文件夹。 ,5,将LLB作为文件夹 LLB是LabVIEW特有的文件格式,可以把多个VI或自定义控件压缩存储在一个LLB类型的文件中。选择该复选框,将LLB文件作为文件夹后,可以选择其中包括的文件。不勾选该复选框,则只能选择LLB文件,而不能选择其中包括的文件。 ,6,起始路径在这里可以指定初始路径。如未指定初始路径,将默认使用最近打开的文件路径。指定该项 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 41 LabVIEW 后将显示指定初始路径下的文件和文件夹。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 42 第章打开LabVIEW编程之门 1.4.5 下拉列表与枚举控件下拉列表与枚举控件从它包含的数据类型来说,属于数值控件。它们都是用文本的方式表示数值。下拉列表有多种表现形式,包括文本下拉列表、菜单下拉列表、图片下拉列表,以及文本与图片下拉列表。菜单下拉列表和文本下拉列表中,文字的输入可以通过快捷菜单中的“编辑”项进行。更简单的方法则是调用属性对话框,然后在“编辑项”属性页中设置。图片下拉列表和文本与图片下拉列表只能通过快捷菜单编辑。选择合适的项目后,可以从剪切板导入图片,也可以从文件夹中直接拖动图片到图片下拉列表。文本与图片下拉列表中的文字,则是通过工具按钮中的“编辑文本”按钮添加的。下拉列表用文字或者图片的方式表示数字。数字可以是整型数,也可以是浮点数。既可以是有序的,比如从0开始递增的整型数,也可以是无序的,由用户自定义它代表的数字。下拉列表上的各项,可以设置为启用或者禁用。如果设置为禁用,则该选择项目用灰色显示,不允许选择。下拉列表另外一个特有属性是“是否允许运行时有未定义值”,默认是未勾选的。未勾选的情况下,只能选择设计好的条目。勾选后,将自动增添一个其他项。勾选该项,列表框边上将出现一个数字框。在框中修改数字并回车,列表框将采用用户输入的新数值。枚举控件与下拉列表控件非常相似。枚举控件只能代表整数,而且是有序、自动分配的。其中自定义枚举控件非常重要,广泛用于状态机中。 1.4.6 数组控件及其属性设置数值型控件、布尔型控件和字符串型控件,它们的共同点是都包括一种基本的数据类型,如整数、浮点数和字符串等。基本数据类型在LabVIEW中也称做标量。右击数组框架,可出现常见的控件选板。选择合适的输入控件或者输出控件,就建立了数组。也可以在前面板中先创建合适的控件,然后拖动到数组框架中。此时建立的数组只包括控件的类型,未包含任何实际数据。同时控件发灰显示,数组包含的元素长度为0。沿着水平或者垂直方向拖动数组,同时显示多个数组元素。单击其中一个元素,则此时数组就包含了实际元素,包括被单击的元素与其前面的所有元素。实际元素不再处于发灰的状态,变成有效状态。数组框架的左侧是数组的索引框。LabVIEW的数组是以索引号0表示数组中的首个数据的,临近索引号的控件就是索引代表的数据。图1-52中,索引号99所代表的数据就是离它最近的那个布尔控件,当前值为TRUE。可以看出,该数组有100个元素,索引号为0~99。图1-52 数组建立过程数组中索引号代表的是与索引距离最近的元素。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 43 LabVIEW 通过上面的方式建立的数组是一维数组,而LabVIEW支持多维数组。增加数组的维数可以采用以下三种方法。 , 在索引框的快捷菜单中,选择“增加维度”项。 , 直接向下拖动索引框。 , 使用属性对话框增加维数。相应的,删除维数,可以在索引框快捷菜单中,选择“减少维度”项,也可以直接向上拖动索引框。通过拖动索引框,可以增加或者减少数组的维度。数组控件的属性设置比较简单,主要是设置是否显示索引框、增加或者减少数组间隙。在数组元素较多的时候,可以显示水平或者垂直滚动条。滚动条是水平的还是垂直的取决于数组控件是水平显示还是垂直显示。多维数组可以同时显示水平和垂直滚动条。数组中的元素可以是各种类型的控件,但是不能是数组的数组,也就是说,数组包含的元素不能是数组。数组中的元素除了它所代表的值以外,其他是完全相同的,具有同样的标签、标题以及其他属性。 1.4.7 簇控件簇和数组是LabVIEW最常见的复合数据类型,簇类似于C语言的结构和VB中的记录。在描述一个外部现象时,使用簇是必不可少的。各种编程语言无一例外地提供了类似于簇的数据结构,主要是因为这种数据结构很好地实现了数据的分类和分层。在此基础上,诞生了类的概念和面向对象的编程语言。可以说簇这种复合数据类型是LABIVEW的核心数据类型。 1,簇的创建簇控件和数组控件位于同一个控件选板中,创建簇的基本方法和创建数组类似,具体操作如下。单击控件选板中簇控件,随着鼠标的移动,出现簇的虚框,鼠标移动到合适位置后,单击前面板,簇的框架就建立起来了。右击簇的框架,即出现控件选板。选择合适的控件作为簇的一个元素,加入至簇中,也可以首先在前面板创建所需的控件,然后拖动到簇框架中。重复上面的过程,依次加入所需的元素。需要注意的是簇也分为输入控件和显示控件两种,至于到底属于哪种则取决于输入的第一个元素是输入控件还是显示控件。如果是输入控件,则整个簇变成输入控件。后续加入的元素即使是显示控件,也自动转换成输入控件,反之亦然。当然,整个簇可以通过选择快捷菜单上的选项,转换成输入控件或者输出控件。 2,簇的大小和排序与数组不同的是,簇中的每一个元素都是相互独立的,具有自己的标签和标题。每个元素都可以通过各自的属性对话框修改相应属性。簇本身的属性非常简单,除了标签、标题、可见性等通用属性外,只具有几个特别的属性,例如快捷菜单“自动调整大小”和“重新排序簇中控件”中所包含的属性。 “自动调整大小”属性中包括四个选择项,分别是“无”、“调整为匹配大小”、“水平排列”和“垂直排and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 44 第章打开LabVIEW编程之门列”,如图1-53所示。选择“无”的情况下,簇的框架大小和控件分布完全由用户决定。若选择“自动匹配大小”,则控件的分布由用户决定,框架自动缩小,匹配控件。选择“水平排列”和“垂直排列”时,控件分布和框架的大小都是LabVIEW自动调整的。图1-53 簇的调整方式及效果 3,簇的逻辑次序簇控件的一个极其重要的特性是逻辑次序。对于簇中的元素,根据添加元素的先后,最先加入的元素的序号为0。根据添加的次序,序号自动排列,比如0、1、2等。与簇相关的函数有些需要根据它的序号操作,因此正确排序极其重要。簇的序号与元素控件的位置无关,只与生成次序有关。通过簇的快捷菜单可以重新定义簇元素的内部次序。具体方法为,如图1-54所示,启动排序窗口,光标变成手型光标。按照0、1、2……的次序分别单击簇元素,进行重排。单击工具条的“确认”按钮,将使修改生效。如果单击“取消”按钮,则放弃修改。图1-54 簇元素排序 4,簇的自定义簇作为复合数据类型,常常用做一种数据结构。在多个VI中,通常需要采用同一数据结构,然后利用数据流相互传递数据。这种情况下,簇的作用就非常明显了。我们可以在一个VI中创建簇结构,然后采用复制的方法,使各个VI采用相同的簇。上述方法存在一个致命的缺陷,如果簇结构中需要增加一个或多个新元素,则每个子VI中使用的簇结构必须重新构造。通过严格自定义簇控件就可以轻松解决这个问题。严格自定义簇控件后,簇的定义保存在单独的文件中,每个使用它的VI都和这个文件保持链接关系。因此,对这个文件的修改,将自动体现在各个使用它的VI之中。这样就一次性地完成了整个修改。程序中所有用到的簇结构,要尽可能地使用严格自定义方式。数组可以在运行中改变大小,而簇在运行中不能改变大小。簇的运用非常重要,通过简单的簇结构,可以构造出复杂的簇结构,即簇的嵌套。下面通过创建雇员信息簇,说明如何构造自定义簇。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 45 LabVIEW 雇员信息可以大致分成两部分,与公司无关的信息,比如姓名、年龄、性别等。与公司有关的信息,比如职务、工资、部门、工作年限等。前者可以称之为个人信息,后者称之为基本信息。下面来建立个人信息簇和基本信息簇。打开自定义控件编辑器。个人信息簇的元素包括姓名、年龄、性别,住址、身份证号、电话号码,输入完成后, 建立图标,存储文件。基本信息簇的元素包括职务、所属部门、工资、内部电话等,如图1-55所示。图1-55 严格自定义类型的簇建立雇员完整信息簇,完整信息簇中包含两个元素,分别为图1-55中的两个自定义簇。 1.4.8 时间标识控件与波形数据控件时间标识控件和波形数据控件是LabVIEW中特殊的控件,这两类控件存在密切关系,波形数据中的开始时间元素就是时间标识控件。 1,时间标识控件为了描述和使用系统时间,LabVIEW专门提供了时间标识输入控件和显示控件。需要注意的是,时间标识控件与数值控件位于同一个控件选板中,这也说明时间标识控件所包含的数据本质上是数值类型。时间标识输入控件从外观上看,非常类似于一般的数值输入控件。控件的左侧有增量和减量按钮。增减量默认情况下为1,当光标定位在文本区域内的时、分、秒、年、月、日中的任何位置时,按照光标所处的位置,进行加一或者减一的操作。时间标识输入控件的右侧是时间/日期浏览按钮。单击“浏览”按钮,弹出时间日期对话框。在时间日期对话框中可以设置时间标识输入控件所代表的时间。在快捷菜单或属性对话框中可以选择是否显示浏览按钮。时间日期对话框使用起来非常简单。如果是新创建的时间标识输入控件,打开此对话框后自动定位到当前计算机系统日期。即可以通过文本编辑的方式修改时间,也可以通过鼠标选择年、月、日,设置完成后,单击“确认”按钮,所设置的时间和日期生效。 LabVIEW内部使用双精度浮点数表示时间,单位是秒,同时根据当前的操作系统决定时区。新创建时间标识输入控件时,默认的双精度数是0,代表的绝对时间是1904年1月1日上午08,00,00。数值0表示的中国标准时间是1904年1月1日早晨8点。 and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 46 第章打开LabVIEW编程之门时间标识控件虽然比较简单,但是时间和日期的表现形式却非常丰富。通过时间标识控件的属性对话框,根据用户的需要,可定制时间标识的显示方式,如图1-56所示。图1-56 时间标识显示格式 LabVIEW包括的大量预先定义的时间格式,可以通过“时间标识”选项卡直接选取,通过选项卡中的“高级编辑”模式,还可以自定义时间和日期的显示方式,包括格式时间、日期字符串的自定义。格式字符串以“%”开头,必须包括在时间容器中,其格式如表1-4所示。表1-4 时间字符串格式列表名称格式说明与示例其他的格式字符串必须位于时间容器中,可以多行设置多个容器,实%< >T 绝对时间容器现时间标识的多行显示。示例,%<%H>T显示24小时制的小时数 %a 星期名称缩写星期名称缩写,对于中文操作系统,与星期名称相同 %A 星期名称以中文大写的方式显示星期数,比如,星期四 %b 月份名称缩写月份名称缩写,对于中文操作系统,与月份名称形同 %B 月份名称以中文大写的方式显示月份,比如九月、十月 %d 第几天/日显示年、月、日中的日 %c 默认日期格式按照计算机操作系统默认的格式显示时间日期 %H 24小时制小时数在24小时制方式下显示小时数,01,23, %I 12小时制小时数在12小时制方式下显示小时数,01,12, %j 一年中的天值显示当前日期是这一年的第几天 %m 月份显示当前日期中的月份 ,01,12, %M 分钟数显示当前时间的分钟数,00,59, %p AM/PM标志显示当前时间是上午还是下午,中文显示 %S 秒数显示当前时间中的秒数,00,59, %u 小数形式的秒值小数点后显示的是毫秒数,digit表示小数点后的位数。例如,%5u %U 一年中的星期数显示当前日期是该年度的第几星期,0,53,,星期日为每星期的开始 %w 星期数以数值的方式显示星期几。比如,4表示星期四,0,6,,0表示星期日 %W 一年中的星期数与%U类似,区别是%W以星期一作为一星期的开始 %x 本地日期格式本地日期显示方式。显示方式为,2008-9-11 %1x 长本地日期格式显示方式为,2008‘年’9‘月’11‘日’ and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 47 LabVIEW %2x 长本地日期缩写中文操作系统,与%1x 相同 %X 本地时间格式本地时间显示格式为,HH,MM,SS,比如10,48,32 %y 两位数年份以两位数方式显示年份,比如,2008 显示为08 %Y 四位数年份以四位数的方式显示年份,比如,2008显示为2008 %z 与通用时间时差中国标准时间与通用时间的时差为08,00,00 时间标识输入控件可以设置范围属性。例如,中国标准时间默认的时间输入范围是从1994-1-1 08:00:00开始,最大到2038-1-19 11:14:07。 2,波形数据控件波形数据是LabVIEW特有的数据类型,在数据采集卡采集外部物理量的过程中,一般按照采集卡内部设定的扫描时钟,等时间间隔逐次采集。描述这样一个采集过程,需要三个要素,起始时间、时间间隔和采集的数值组成的数组。正是由于波形数据的特殊性,波形数据控件位于IO控件组中。波形数据控件由三个控件组成,时间控件t0表示开始时间,数值控件dt表示时间间隔,数值控件Y数组表示连续采集的数据。通过波形控件,可以非常容易地计算出每个数据对应的时间点。第,个数据的时间点Ti=t0+i*dt,i表示数组,的索引号。 1.5 小结本章从LabVIEW最基本的控件开始,介绍了如何创建、编辑和调用VI。VI是LabVIEW最基本的概念,贯穿于LabVIEW编程的始终,尤其是其丰富的属性设置,使用起来极其灵活。 VI的设计具有明显的层次结构,模块化编程是LabVIEW编程的突出特点。LabVIEW编程的其他重要特征,比如数据流和多线程,本章只是简单提及,在后续章节将专门讨论。在本章的后半部分,使用较大篇幅介绍了LabVIEW常规控件的用法,特别是数值型控件和布尔型控件。它们使用得非常广泛。除了基本控件之外,LabVIEW还提供了大量的高级控件,将在后续章节介绍。 ? ? ? and performance test copies of the record. If necessary, review should be carried out; 4) for spring hangers (included simple spring, hangers and constant support hangers) it should also be recognized as setting and locking of loads. 5) check the surface quality, folded layering and without cracks, rust and other defects. 5) after completion of the test and control drawing number one by one, by series baled. Color alloy steel parts, the parts marking installation location and rotation about the direction you want. 7.3.14. hangers installation 7.3.14.1 hanger layout a. a clear design of hanger should be installed strictly in accordance with the drawings and designs shall not be installed wrong, missing, etc. B. own arrangement of piping support and hanger set and selection should be based on comprehensive analysis of general layout of piping systems; cold installation of steam pipe with particular attention reserved for compensation of thermal expansion displacement and orientation. C. support systems should be rational to withstand pipe loads, static load and incidental load; reasonable piping displacement; guaranteed under various conditions, stress are within the allowed range. Strength, stiffness, and meet requirements to prevent vibration and soothing water, without affecting the adjacent equipment maintenance and other piping installation and expansion. D. equipment connected to the interface to meet pipeline thrust (torque) limit requirements; increase the stability of piping systems to prevent pipeline ... Tube wall thickness (mm) 2-3 4-6 7-10 weld form no slope mouth weld strengthening height h (mm) 1-1.5 1.5-2 weld width b (mm) 5-6 7-6 has slope mouth weld strengthening height h (mm) 1.5-2 2 weld width b (mm) cover had each edge slope mouth about 2 mm argon arc welding weld strengthening surface height and width tube wall thickness (mm) 2--3 3--4 5--6 weld form weld strengthening height h (mm) 1-1 .5 1.5-2 2-2.5 width b (mm) 48

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labview宝典第一章

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