Tips for creating Sub VI

Everyone knows the method of creating the SubVI by using wiring tool & connector pane (click on control & click on necessary connector pane terminal).The easy & quickest method for creating the SubVI is,

Select the part of the code which one you like to create as a SubVI & go to Edit menu then select the option “Create SubVI”(See Picture 1) .Now the selected part of the code is automatically converted into a SubVI(See Picture 2).

Tips for insert the function in-between wiring

Inserting the function tool in-between wires is easily done by right click->Insert->select tool from function palette. For two input function (like Add,Subtract… ) insertion in-between wiring you have two options, if you like to insert the first terminal of the function on the wiring- Right click below the wiring and insert it or you like to insert the second terminal of the function on wiring- Right click above the wiring and insert it. (See Picture 1)

Swapping the wire terminals (two input function)

If you have function of two inputs like Add, Multiply…etc , you can easily swap the input wire terminals without deleting the wires. For example you have connected x1,x2 as input terminals in Subtract function, the swapping of x2 into x1 and x1 into x2 is done by the following method,

Keep auto tool selection enable – move the mouse over subtract function input terminals and press control key you got a symbol like -8 just click it now you got swapped input terminals.

Randomly mixing the array elements

There is no direct tool for mixing the array elements randomly in LabVIEW 7.1 & below versions .Use the following method for mixing the array elements (See Picture 1)

Limit string length of the string control

In some string control using user interface applications need the limited string length option for restrict the user from entering the unnecessary strings .My method for limiting the string length is (See picture 1),

String control connected with String Subset(with length) and the substring connected with the local variable of that string control.String Subset length 10 constant denotes the Maximum string length of that control.Select the update value while typing option of the string control by Right clicking on control for run time string length control. If any other way please let me know.

Quickly entering items into Ring & Enum control

The conventional method (Right click-> Edit items) for entering the items into Ring control is uses only when you need the sequential value changes for the items. If you don’t need the sequential value changes for the items the easiest & quickest method for entering items into Ring & Enum control is,

Select Edit Text from the tools palette and click inside the control -type the item & press shift + Enter button then again enter item .

Tips for Case Structure

The Case selector terminal is accepts string,enum,boolean,integer types.If you like Case Structure connected with string should be case insensitive choose Case Insensitive Match option by Right click.(See Picture 1)

















Radix selection is also accomplished for numeric control connected case selector by Right click->Radix-> Hex or something .(See Picture 2)

Working on Compound Arithmetic tool in LabVIEW

For arithmetic calculation such as addition,subtraction etc we are using add,multiply & more tools from the Numeric palette.If many inputs are using in the calculation, the block diagram should be little bit extended by more Numeric tools & wiring. For a clean block diagram use Compound Arithmetic tool from numeric palette.By using this tool the addition & subtraction ,Multiplication & division calculations are easily accomplished without using the separate tools like Add, Subtract, Multiply, Divide.For example, Result=I1 + I2 –I3 calculation is done as per below (See Picture 1 for both two methods).

The invert terminal denotes the opposite calculation(In addition operation invert works as subtraction & Multiplication operation invert works as division ).To get invert input terminal- Right Click on the terminal and choose invert.Boolean operations is also done in that tool by changing its mode(By Right Click on the tool->Change mode->OR).

Find number of times occurring element in an array

To find the particular element occurrence in an array is easily accomplished without using any loops. The method is (See Picture 1 & 2),






























This method is work on both numeric & string array.(for more methods see NI Discussion Forums )

Converting string array to concatenated string

The conversion of string array elements to concatenated string is easily accomplished without using for loop with shift register concatenation .For concatenating the array elements into string without any delimiter is easily attained by the tool Concatenate Strings.Get Concatenate Strings tool by, Function palette->string-> Concatenate Strings
Wire the string array to Concatenate Strings single terminal and create the indicator to see the concatenated String (See Picture 1 & 2).

The numeric array elements concatenation is also possible by converting the numeric array to string array and Concatenate Strings then convert back to numeric indicator( See picture 3 & 4).

Checking the File existence in particular path

The most of the projects file creation & deletion operation is needed. On these operations file existence checking for particular file path is important. For file existence checking there is no direct tool in LabVIEW 7.1 and below versions. But its accomplished by File/Directory Info tool.

To get this tool,

Functions Palette->File I/O-> Advanced File functions-> File/Directory Info.

Wire the error out of this tool to case structure . The No Error case denotes the File is exists,if error is getting means the file does not exists (See picture 1)

Getting Application Path for an EXE

In development environment the the current VI path tool gives the path. For an EXE we are not getting the exact path. For gettting the current VI path for an EXE use property node from
Functions palette->Application Control->Property Node, The properties Application kind & Application directory are selected by
click on the property node ->Application->Kind & for next property
click on the property node ->Application->Directory Path (See Picture 1)















Connect the Application kind to case structure terminal to get the Development system,Run time System and more kinds..
Use the Directory path wire for getting current path for an EXE (See Picture 2)