negative voltage reading problem with cmd.c and ni_pcimio

Hi, 
I've been battling a weird problem today of not being able to acquire
negative voltage values with my NI PCI MIO card. When executing the cmd demo
program, for example, every time the input voltage is < 0, the acquired
value shoots up to 63000 or so (max res for my card is 4096). I have my
range set to 3 (bipolar +/-1V). when I set it to unipolar 0-5V, the negative
values just give 0 and everything looks fine.

Maybe my problem is hardware related, or I'm just missing something very
simple because I'm very tired, but I am out of things to try. Please let me
know if you have any suggestions or have experienced similar problems.

Thank you,
Naoko Kurahashi

Received on 2004-06-15Z01:41:42