NI PXI 6281 Analog Input has -4.2V offset

[hilary]

I get a sine wave through PXI 6281. But there is a -4.2V offset. I tested the input signal on oscilloscope, it is fine. So what is the problem of PXI 6281. How can I configure it back to normal?

Thanks,

[devchander]

Probably, it is just a mismatch in connecting signal in appropriate mode.

Check your connections.

Wheather you have connected in Single ended (RSE or NRSE) or Differential mode, and if you are acquiring for the same mode of signal connection.

[Travis G.]

Hello hilary,

Are you seeing this offset when acquiring data from an analog input channel with your PXI-6281, or when generating data with an analog output channel?  I can't tell from your initial post.  Assuming you are performing analog input, devchander may be right about the measurement mode being the cause of the problem.  If the sine wave source you are reading is referenced to a different ground than the DAQ board, you will want to use a Differential measurement mode to avoid a ground loop.  Take a look at the Measurement System Types and Signal Sources section in the NI-DAQmx Help (Start > All Programs > National Instruments > NI-DAQ) for more information about the different measurement modes.

Travis G.
Applications Engineering
National Instruments
www.ni.com/support