SCXI AC Voltage Measurement

[cosgrove]

Hi,

I am attempting to measure a shunt voltage (AC) using an SCXI 1001 / 1102 / 1300 set up. Data transfer is via SCXI 1600 USB using windows XP. I've installed the XP hotfix associated with data corruption issues.

I've been attempting to collect at 100k and get total nonsense when viewing the waveform in MAX. I've checked the channel with a DC voltage and it appears correct and the AC signal is correct when measured with a multi meter at the terminal block and with a scope.

This is a differential measurement 0-100mV AC @ 60Hz. Task settings: continuous / 200k buffer size / 100k rate

Any suggestions?

Thanks in advance!

Jon

[BenRobinson]

Hi cosgrove,

How do you display the data collected? Is it in a log file or a graph/chart? Have you tried a different channel on the module or a different chassis? What is the signal source and how is it connected to the SCXI system? You could try grounding the signal by adding large (100k or more) resistors that lead from the positive input to ground and the negative input to ground. Have you tried varying the sample rate? A 60Hz waveform would be perfectly defined at far less than a 100 kHz sampling rate.

Let me know if any of this improves the problem and we can work from there.