Waveform chart update rate

[swap15]

Hello,

I have one application in which I am measuring two voltage signals and feeding these signals to Mask and limit test VI to check if the signals are within range. 

I want to have 1000 samples7sec (1KHz sample rate). The software is running well but the only problem is with waveform chart updating. If i execute the producer loop with 1 ms , in log file I have 1000 samples/sec BUT I can't see anything on the waveform chart (second graph on GUI). I mean, I cant see the the tolerances and my i/p signal.

when I execute the producer loop with 2 ms, I can see the signals on waveform chart but in logfile I have 500 or less than that samples/sec. I tried to change the smapling rate but no success.

Any help would be appreciated.

Plz see the attached sample VI

[crossrulz · Accepted solution]

1. With Continuous Sampling, you do not want to set the buffer size.  Just let it be the default (which is pretty large).

2. You actually do not want a wait in your producer loop.  Instead, you should tell the DAQmx Read to read something like 100 samples.  The waiting for the data to come in will limit your loop rate.

3. Your second chart is actually a graph.  A graph does not have any history and only shows exactly what you gave it last.  So if you were trying to get all of the samples every 1ms when you are sampling at 1kHz, you will have 1 sample being read from the buffer and only that 1 sample will be on the graph, making it appear like there is nothing in the graph.  When you go to 2ms, you are getting 2 samples to show up on the graph.  So I think you want to replace that with a chart.

[swap15]

hey thanks for this useful information.