Analog issues for a non hardware person.

I have been banging my head over an analog issue with a National Inst PCI-6025 board (DIO works fine).  I am a software person and not a hardware person.  We have set up though their SCB-100 wireing box some hardware that gives power while in its neutral position of aprox 2.5 volts DC between AIGND (pin 1) and ACH0 (pin 3) that is measurable with ease with a multimeter.  We also have the same powersource on another item that goes though the device and gives a second reading on pin 5 (ACH1) (its a Aircraft stick which has a lat and long pot).  We have a second power source that drives a third device between AIGND and pin 13 (ACH5) that reads about 4 volts in its current position (throttle).  The problem is that trying to read the chanels (currently have a program that is reading all 16 channels with comedit_data_read_delay at range 1 (-5 v to +5 v), AREF_GROUND, and a delay of 40000) I get pretty much random noise of -1v to 1v on all channels except chanel 5 which bounces from -3 volts to 2 volts to 4 volts and back and fourth.  I figure this is a hardware wireing issue and have tried moving the grounds to AISENCE instead to see if that helps anything which it does not.  Another test I ran was I tried to change the aref to AREF_COMMON, about 1/3 of the readings are pegged at 5 volts (on all 16 channels).

Any assistance would be appriciated,

Ingi A. Ford

Received on 2005-11-17Z16:29:34