PXI-5152 synchronization

[mkh]

Greetings,

I am using a PXI-5152 digitizer board in LabVIEW.  I am digitizing a 500ns pulse in a 1 KHz signal on channel 0 of the digitizer.  The digitizer is set to trigger on the rising edge of this pulse (I think).

I would like to output a pulse on the PFI 0 or 1 line synchronized with the trigger.  I am using the niScope Export Signal vi.  When I set the Export Trigger input to Reference Trigger, and the port to PFI 1, I get a pulse out of PFI 1 that coincides with the digitized signal on channel 0.  When I look at the output of PFI 1 on an oscilloscope, along with the 1 KHz input signal, the output from PFI 1 is synchronized with the 500ns pulses, but it does not occur on every pulse.  It occurs randomly.

What else do I need to do, or what do I need to change, to get the output of PFI 1 to be synchronous with the trigger on input channel 0?

Thanks for any suggestions or assistance,

Mike H.

[Austin_W]

Hi mkh,

Can you be more specific about the signal you're digitizing?  How often does the 500ns pulse occur?

[Stephenah]

mkh,

  Your VI reconfigures and restarts the digitizer after every record, which means you will probably miss some pulses while you are reconfiguring.  You want to configure for multiple records to ensure you don't miss a pulse.   You should look at the following installed examples for multirecord acquisition:

 niScope EX Multi Record.vi

 niScope EX Multi Record Fetch More Than Available Memory.vi

Stephen

National Instruments

[mkh]

Thanks to all for the responses.  I did figure out the problem, and some limitations with the board.  After reconfiguring my VI, I found out from NI that the board cannot simultaneously have synchronized output of a digital line with the trigger based upon the analog input and unlimited, continuous acquisition at the same time.  I was able to get an output pulse on PFI 1 synchronized with the trigger created by the digitized input, but only for a finite number of requested acquisitions.  This still works because the requested number may be very large, and at my acquisition rate of 2000 per second, I can set it to run for several hours before the acquisition total number is reached.

Thanks again,

Mike Hinckley