For loop rate and real time data

[dachal1]

I am new to LabVIEW. I am trying to read and plot the signal area in oscilloscope with labview VI.I tried it with "FOR loop" and waveform chart. It worked, but the issue is For loop functions in its own rate. I want my VI to pick the area, only when it change the value from the initial value(oscilloscope captures a new signal every time when it's been triggered and gives a new value for signal area).Right now my VI seems to be faster and re-read the same data and miss some data.What should I add/try to pick the signal area only when it changes.

[crossrulz · Accepted solution]

You could just put a wait inside of the loop.  The other option is to communicate with the oscilloscope to figure out when it gets a trigger, wait for the acquisition to complete, and then read the data.

[Yamaeda · Accepted solution]

If you only want something to happen on a value change, you should use a Value change event. 🙂

[RTSLVU · Accepted solution]

I don't know what scope you are using but every scope I have used with LabVIEW had a VI to set/check the trigger status.

So instead of just constantly reading the scoop (1000 times with out stopping?) whether it has triggered or not...

1. Set the scope to do a single sweep when triggered. 
2. Arm the trigger
3. Wait for the scope to trigger and acquisition to complete
4. Transfer the sweep data
5. goto 2, repeat until done