NI USB6210, problem to trigger on a Digital Edge with Measurement&Automation

[daniel_blanzat]

Hello,

I use Labview version 8.5.1, NIDAqmx driver version 8.7, Measurement&Automation explorer 4.4.1 and a device NI USB6210.

I create a task with Mesurement&Automation to do a voltage acquisition on the channel AI0.

I want to use the digital trigger function with the channel PFI0 . I connect a square signal on the channels AI0 and PFI0. I set the edge to RISING for example. When I do several acquisitions, and I notice on the curve that the device USB6210 doesn't trigger properly, sometimes the trigger edge used is RISING and sometimes FALLING.

Could you help me? Is it a driver problem?.... 

Thanks in advance, Daniel.

[Mathieu_R.]

Hello Daniel,

First of all, what is the frequency of this square signal? How do you generate this square signal? If it is possible, decrease the frequency of this input signal, and tell me if the behavior you described still occurs.

What is sample rate of your acquisition? How many analog channel are you reading? The purpose of thoses question are to get the same conditions as you, in order to reproduce the issue.

Cordially,

[daniel_blanzat]

Hello and thanks for your answer.

The frequence is low, around 1Hz and the signal is generated by a function generator. The measurement shows that the problem doesn't depend on the sample rate.

I spoke about my problem with France-support yesterday. The problem is due to the rising(falling) time between 0.8V and 2V. I had a big capacitor in parallel connected in the signal output of the generator and the rising time was higher than 20ms. If I move this capacitor, the system works properly, so it triggers on the good edge. Now, the rising(falling) time is shorter than 50ns.  

Daniel.

[Mathieu_R. · Accepted solution]

Ok, nice to hear that everything is working as expected.

Bonne continuation,