NI 9237 Not reading Correctly

[ASTDan]

Hello,

I have a NI 9237 with a Compaq DAQ chasis. I have hooked up a power supply to the AI + and AI - Input terminals. When I look at my signal in Max I get the attached waveform. I have looked at the input signal with my scope and it doesn't look like the attached waveform. The peak value of the waveform seems to be the desired value.

Any Advice?

Thanks

Dan

[AnalogKid2DigitalMan]

Dan:

Are you sure you are reading the correct channel for the pins you are wired up to? That almost looks like 60Hz AC power line noise from an unwired adjacent channel. Peak is less than 7mV (0.007).

[ASTDan]

I have the gray wire Connected to the negative terminal of my power supply and the white wire connected to the positive terminal of my power supply (using a RJ 50 cable). I have checked all the channels. Could my cable be bad?

Dan

QUOTE (AnalogKid2DigitalMan @ Mar 11 2008, 01:22 PM)

Dan:

Are you sure you are reading the correct channel for the pins you are wired up to? That almost looks like 60Hz AC power line noise from an unwired adjacent channel. Peak is less than 7mV (0.007).

Also the peak is really 70mV

I had to turn on the Scale using Excitation. I have the excitation set to 10V.

Thanks

Dan

[ASTDan]

OK I think I have found the problem.

My poopy power supply is not a nice clean waveform and the strain gauge has some magic filtering on it. The combination of those 2 produce the wavform I have been seeing.

Dan