NI Scope Swept Sine Timing Issues...

[josh100482]

I am using the NI High speed PCI 5124 Digitizer which samples up to 200 MHz per channel with 12 bit resolution, 32 MB on board memory.  I have created a sine sweeping program that calls the NI-Scope VI's and calculates the bode plot for these.  It follows the same principles of NI's Sound and Vibration's Swept Sine program, but simplies it a lot.  I am having timing issues with my program.  It will only run in the 30kHz-700kHz range.  All frequencies swept below and above these frequencies shows and error of: "Maximum time exceeded before the operation completed".  My program allows for the sampling frequency to be 10X the current testing frequency.  I am trying to run a sweep from 100 Hz to 5MHz.  Any suggestions would be appreciated.  I can include the code as well if anyone would like to see it.
Josh

[JoeFriedchicken]

Hey Josh,

This error typically occurs when there is a triggering problem.

I would first verify your triggers: are you sending them from your sine source? Are you triggering on the correct channel? If your trigger settings are correct, then you can try increasing your timeout to allow the VI to wait longer for one to arrive. If none of these work, please provide some more information on your setup. How are you generating your sine excitation? What kind of triggering are you using? If you could provide a screenshot of your code, that may help me diagnose the problem.

[josh100482]

I believe I am triggering correctly.  I am sending out a sine wave using a signal generator via GPIB.  Then it is calling my program in a sequence structure and the bottom level program is attached.  This is where the problem should be I would think.  I basically just amended an example problem.
Thanks for you help!
Josh

[JoeFriedchicken]

Hey Josh,

I looked at your block diagram and noticed that you're using the default analog reference trigger settings: trigger on channel zero at 0V on a rising edge. If your signal on channel zero is attenuated outside of the band that currently works, then the scope won't have a signal to trigger on.

If your function generator has a trigger or sync output, I recommend connecting that output from the function generator to the TRIG on your scope. In your VI, set the trigger source for your "Analog Edge Ref Trigger" VI to 'External TRIG'. This will supply a clear 0-5V trigger for the scope to use when it takes a record.

If adding an external trigger doesn't work, increase your timeout (using the fetch VI's timeout input) to 10 or 15 seconds.

If you're still having problems, please tell me a few more things:
 1) The record length
 2) The sample rate
 3) The exact error code (in hex or decimal)