Problem with PCI 6023E

[xstarx]

Hi

I'm trying to acquire data from a switch using PCI 6023E. I have tried to read the data using the Visual C++.net example provided by NI (Analog in - Measure Voltage -ContAcqVoltageSamples_SWTimed). It seems to be working. However, the value of the data collected keeps rising with time, for more than 10 minutes -- from around -2.5 up to3.0 when the switch is not activated. If I activated the switch, the value would increase by about 5. May I know if this is common? I thought it shouldn't have such a long settling time?

 Also, Today, I transfered the PCI card to the PCI slot of another PC and the PC would hang after I connected the CB 681lpr to the PCI board. I am wondering if I have missed out some steps that such a problem occurred?

Thanks a lot!

[Jason_D]

xstarx,

This sounds like a connection/grounding issue to me.  What type of connection are you using (differential, reference single ended, etc)?  Are you using bias resistors if applicable?  I would encourage you to check out the Field Wiring Guide.

[xstarx]

Sorry for the late reply. An NRSE was used.

One end of the switch is connected to ACH1, another end to AIGround.

One end of a resistor is connected to ACH1, another end to +5V.

One end of a wire is connected to AIGround, another end to AISENSE.

Now, the drift is getting larger. After it settles down, a voltage value of about 7V is obtained at state "0" and a voltage value of 10V (the max) is obtained at state "1".

Thanks.

[Jason_D]

xstarx

You will probably want to look at the document I provided above again.  It seems like it is suggesting quite a different wiring than you have.  If this still doesn't work you might want to consider some of the things in this document.

[xstarx]

Thanks! It works now. I removed the AISENSE wire. Also, I just realized that I forgot to change the AITerminalConfiguration in the C++ program!