cDAQ 9775 limiting input range

[Alain_V]

Hello everbody,

We just bought the NI 9775 compaq DAQ and we are very happy so far with the results.

Sometimes we have to measure signals in the range peak to peak of 1 volt.

So it is a good practice to downsize max range of your input channel according to the to-be-measured signal.

In the function block we are using, there are two inputs exactly for this purpose (see attached image).

If we wire these inputs to measure a max voltage of 1 volt and a min of -1 volts but this does not change the input range.

We keep measuring at the max range of our NI 9775 of 10v positive and -10v negative thus a total range of 20v.

We are seeing this because the trigger we are using is 10 volts and it should saturate at 1 volt. We are measuring the full 10 volts.

Also, we added a Channel-node at the end of the complete chain in the block diagram which confirms the range used being 10v and -10v.

Is there a way to limit the input range to +1 volt and -1 volt ?

Thanks !!
Alain V

[santo_13 · Accepted solution]

It looks like NI-9775 has only one range and hence it always chooses 10V range.

https://www.ni.com/docs/en-US/bundle/ni-9775-specs/page/specs.html

If you need multiple ranges, you would have to get a different C-Series Analog input module.

[Alain_V]

I was afraid of that .....

Many thanks for helping out !!!

Alain V