DAQ Device Gain Settings

[ProblemNIDAQ]

I am running a PCI-MIO-16XE50 with Nidaq V7.4 Dll's, and developing an application using VB6 on WinXP. For hardware I am using a SCXI-1000 chassis with a SCXI-1120/SCXI-1328 setup.

My problem is that when I try and read voltages from thermocouples, it runs fine except when I change the gain that I send to anything over 100. I need to be able to run the gain at 1000/2000 but this does not appear to work, and I keep getting a result of 0. The expected result is about 0.00005xx V and this is what the Measurement and Automation explorer shows me as the result, with those same gain settings of 1000 or 2000. The functions that I call to get my results are Scan_Op which is followed by AI_Vscale. I have tried some of the other functions (like AI_VRead), but they all appear not to work with a gain of over 100. Thus, help is needed.

Thanks,


Luke

[WM_John_Weeks]

Luke:

That board maxes out at a gain of 100. Perhaps MAX is getting the high gain by setting up some gain on the SCXI module?

[Marni]

Hello Luke.

I agree with John, it sounds like you are not using the scaling on the SCXI modules. When you specify the channel are you using a SCXI channel (ob0 ! sc1 ! md1 ! 0) or a DAQ device channel (Dev1/ai0)? Please let me know if you have any questions. Have a great day!

Marni S.
National Instruments