Error 200019

[nilukas]

Dan, think I need a system in video "NI triggering". When trigger signal will come, that is signal I need , only between rise and fall of trigger signal. Now I use this attached file where is no retriggering, because I tried use your file and I got the same problem (when retriggering is enabled) - no reaction when I disconnect trigger wire. When retriggering is disabled programm doesn't run and with no error. So, now just need acquisition when trigger signal comes in a loop. Now trigger works only once in the first moment. Is it possible to do that?

[Mcdan]

With your new VI, it appears as though you'll start your acquisition with the first trigger you see, then continue to acquire data until you hit the stop button.  Is this the behavior you're seeing?  Is this the behavior you want?

If you want to investigate the issue's your're having with triggers, I would recommend the following approach:

1) Use the VI I attached, and use one of your device's counters to generate trigger pulses.  See if you can get triggering to work that way.  If you do not want to use retriggering, you can remove it, however you'll need to start and stop the DAQmx task in the while loop.  (this is important!!!!)  Do you see an error after you stop your loop?  When you do this, make sure you set buffer size to something small (try 1000 samples).  I still don't have an understanding of how often your system produces valid trigger pulses on PFI0.  As I explained, if it happens frequently you can end up transferring lots data to the buffer and read them for some time after the trigger signal ends if your loop is significantly slower than the frequency at which you receive triggers.  Do you know how long it takes your while loop to run?  Do you know how frequently you receive triggers?  So if you use my VI, with one of your device's counters, we can control the frequency of trigger pulses and make sure our acquisition behaves accordingly.  Once we can do this, we'll know we have the trigger set up correctly.

Note: You can use Counter - Continuous Output.vi to generate your trigger pulse for this testing.  It is an example that should have been installed with DAQmx.

2) Test the source of your trigger pulses.  Use one of your device's counters and do an edge count on PFI0.  Does it see edges on the PFI line?  If it does not, then you'll need to ensure your trigger signal needs to meet the these specifications.  See Digital I/O Characteristics section.  You can use a counter to make other measurement to ensure the trigger signal on PFI0 looks like you think it should.

Note: you can use Counter - Count Edges.vi and Counter - Read Pulse Width and Frequency (Continuous).vi to test your trigger pulse (PFI0).

If you can get these two steps working as expected, then go back and try to get AI to trigger with the signal in PFI0.

Hope that helps to isolate the source of the problems you're seeing.

Dan

[nilukas]

Well now I feel better because finally trigger signal began to react on disconnect. Can I think that trigger signal works right ? 😃  But only one thing is not clear, why signal amplitude is 130 mV in oscilloscope but distribution of about 200 mV ? Unfortunately I can't use counter. Duration trigger signal is about 120 ns