ni 9265 no output

[Greg_Reynolds]

Trying to diagnose a lack of output on a NI 9265 20mA analog output board.  To do this, I've got...

 - 24VDC to Vsup & COM

 - DMM closing the loop AIx & COMx

 - Running Test Panel to adjust the output of a particular channel

When I change the output level on the Test Panel, I see a jump in mA, but it then returns to zero.  I'm expecting the mA output to stay constant and the prescribed level.  Isn't that how its supposed to work?

I see the same behavior when I run a simple AO VI to test the 9265 output.  That is, when I change the FP control input to the DAQmx write data,  I see a jump in the DMM mA reading, then return to zero. Not what I'm looking for.

Thanks for any input on this,

Greg

[AnalogKid2DigitalMan · Accepted solution]

Any chance your DMM is set AC mA and not DC mA?

-AK2DM

[Greg_Reynolds]

Good question.  I'm not that familiar with the DMM, but it did have a units reading mAAC.  That would explain it.  I'll check.

Greg

[Greg_Reynolds]

Yes, that was indeed the issue.  When I switch to mADC mode, I get the output that I specify.

I did observe however that when I stop my DAQ task, the mA output stays on, even though I have a DAQmx Stop Task.vi after exiting the DAQ loop.  For my application, I want to return to 0mA or 4mA on exit.

Thanks for your help!

Greg

[AnalogKid2DigitalMan]

Greg:

Add another set value function to 0 or 4ma outside the loop before the Stop Task.vi.

You're welcome!

-AK2DM

[Greg_Reynolds]

Right, I thought of that too, and that works. But the DAQmx Stop Task function is to "return the state before the Start Task".  That's not happening.

Greg