Thursday, May 13, 2010

Split string characters without using Loop

We can split the characters based on the length.Using this method we can split the string & convert it into array it will be useful on string which does not have delimiters.Search & Replace string function is used to split the string characters.We need to select the "Regular expression" option by right click on the Search & Replace string function.Check the picture for split the string by length 4.Just change the number "4" on search string terminal & give your length of characters to split.Replace String terminal displayed in '\' codes display.

Tuesday, April 6, 2010

Find used Row & Column size of excel file using LabVIEW

Using LabVIEW ActiveX tools we can find the used row & column size of the excel file. See the attached VI snippet (In LV 2009) for the ActiveX code.


Thursday, April 1, 2010

LabVIEW 2009-Tips to create automatic controls & indicators for functions

In LabVIEW 2009, i came to know one interesting feature to create terminal controls & indicators for function. That is as follows,
For example,
1. Keep & select any one function in block diagram(eg: Add function)















2.Select that function.(Now it will be highlight)
3.Use key strokes Ctrl + Space.
4.Next use another key stroke Ctrl+ D (Use Ctrl+Shift+D to create constants).
5.Now you can see the magic .The terminal controls & indicators of that function should be created automatically.














This feature available only in LabVIEW 2009. I tried with some premitive functions & standard VI's its works fine.

Tuesday, November 24, 2009

Dynamic Event-Example for multiple controls value change event

See the simple example picture to know how to use dynamic event for multiple controls value change event. Using this method user can give only one value change event for all the referenced controls.




Sunday, December 7, 2008

Creating & Using Functional Global in LabVIEW

An un-initialized shift register with in the single run loop (Before LabVIEW 8.5 ) VI is Functional global. This VI must having Read & Write operation. Functional global is also called as LV2 global.
This is similar to global variable (Used to read & write the values among the VI’s ).
Some advantages are,
* Avoid racing in value read & write operation
* Easily used among VI’s & subVI’s
* Modification & Addition of more operation is easy
Do not set Reentrant execution property in Functional global VI because it will make racing.
The basic method for creating Functional Global is given below (See Picture)




























Operation enum having Write & Read item. In write case value is stored into shift register .In Read case stored value is getting in the Value Out variable. This stored value is kept in the shift register upto the LabVIEW application is closed. You can use while loop with single run as a Functional global.

Wednesday, May 28, 2008

Tips for timestamp calculations

I was studied the article “LabVIEW tip: easy relative timestamp calculations” from this link.This method is very simple for calculation with Timestamp control.The addition of day,year,hour,min,sec is also done by this method .DBL data type constant with unit label is used for these calculations.See the attached picture for adding one day with time stamp control.

Tuesday, May 27, 2008

Creating Text Labels instead of numeric scale in controls (Gauge,Slide,Dial etc)

Controls like Gauge,Slide,Dial are DBL data type(by default) & having the numeric limits with changeable scale .If you want Text Label for Dial, Gauge… controls follow this method.
Right click on the control->select Text Labels option & Edit the Text Display which is contains the min & max labels as default. The attached picture shows the Dial control with Level 1 to Level 5 text labels.

Friday, May 23, 2008

Creating multiple Controls/Indicators in Front Panel without using any additional variables

In Front Panel multiple Controls/Indicators with same behaviour without using any additional variables is attained by Advanced ->customize option of that control (or) indicator.First select Digital Display option of the control from Right click the control ->Visible Items-> Digital Display then go to customization. Replace the Digital Display by any other control like Gauge, Meter...etc. Repeat the customization to replace the digital display of the new custom control with another control. (See Picture)

Wednesday, May 21, 2008

Disable the Numeric control entry field

In run time restrict the user from typing something into the entry field of the numeric control (or) String control is easily done by the following trick.
Select a "flat box" from decorations->Flat box, resize/move it to exactly cover the Numeric control user entry field and paint it transparent . Group it the flat box & Numeric control and also select “Skip this control when tabbing" option in the key navigation dialog of the control to avoid the tabbing access of the control.

Thursday, April 10, 2008

Tips for getting Drive List of the system

To get the drive list of our system in LabVIEW is obtained by List Directory function which is lied in the Functions Palette -> File I/O -> Advanced File Functions -> List Directory. If you giving empty path as directory path of List Directory function you get the drive list of the computer from the directory names string array. (See Picture).It is a very cool & nice feature in LabVIEW.

Using Description and Tip option

Description and Tip is a very useful option for the controls & Indicators in front panel. Right click on the control or Indicator & select the Description and Tip option. Tip is a popup tool tip shows on run time when mouse over the Front Panel element. Description shows on Ctrl + H help window for the Front Panel element.(See Picture for selecting this option for control)

You can change the Description and Tip of Front Panel elements on run time by its property nodes.

Tuesday, April 8, 2008

Generating alternate numbers periodically

For getting the alternate numbers in loop periodically is obtained by Quotient & Remainder function. If u like to generate the numbers 0,1,2 periodically means connect the Loop iteration (while or for loop based on usage) terminal to Quotient & Remainder function x input & create constant 3 on y input(constant should be addition of one with last number in the periodic numbers).See picture1 for Example(four periods of 0,1,2 numbers generation).

Monday, April 7, 2008

Tips for Unit Conversion

I was studied the article " easy unit conversion " from the following link.

This method is very simple for unit conversion without using the unit label of the control.
This method uses the function - Convert Unit. (See Example)