Using External reference for one channel and others using internal reference in PXI 6733

[kwan]

Hi,

I am using PXI 6733 in my application and I am using 6 channels out of 8, among which one channel is in very low range (0 to 100mV). so I am using external reference source to get better resolution and I want to use other channels using internal 10 V reference. can any one suggest if I can do this? Can I use all the channels in a single task? Or do I need to create a separate task/channel for channel 1 and a separate task for rest of the channels?

Thanks in Advance

[John_P1 · Accepted solution]

Hi kwan,

You can in fact do this.  From the User Manual:

You can connect each DAC to the device internal reference of 10 V or to the external reference signal connected to the external reference (AO EXT REF) pin on the I/O connector. This signal applied to AO EXT REF should be within ±11 V of AO GND. You do not need to configure all channels for the same mode. Using AO EXT REF to reduce the output voltage range results in a higher resolution at the adjusted range.

If you are using clocked AO tasks, you would need to combine all of the channels into the same task.  You can set the channel properties for individual channels as follows:

       

Software-timed AO channels can run in independent tasks if so desired.

Best Regards,

[kwan]

Thanks John P,

I did similar stuff and it worked fine.

One more thing to add, I had a problem of fitting the external reference source in my system, so I have used one of the spare channel as the reference. I hope this should not be problem.

Thanks again.