Analog out has a standing DC voltage

[Ephys]

This may seem like a simple question but I have an older board, PCI-6040E. I am using the latest NiDaq driver and the board is connected to a BNC-2090 box. My problem is that I have a standing positive dc 100 mV signal coming out of both analog outs. Is there any way I can correct or calibrate this through the measurement software? Or any other way I can get rid of this voltage? Thanks

[aNIta B]

Have you explicitly set the ouput to 0V either through LabVIEW or a MAX test panel?  Or is this just a floating output that you're reading? Thanks!

[Ephys]

Actually, I don't use labview. I use the board with general software (Strathclyde Electrophysiological Software, WCP) that can be used with a variety of boards (NI and nonNI). The 2090 analog oust when connected to the powered PCI board in the computer produces an approximate 100 mV output measured on an oscilloscope. The Max test panel can zero it if I put in approximately -92 mV. However, this is only temporary because if I use the analog out with the installed software, the analog output goes back to a 100 mV standing DC voltage.

[Henrik_Volkers]

Date of the last self calibration?( If this card offers it)

You mentioned it's an old card: Maybe there is some dirt somewhere producing the offset?  Is the offset still there if you apply a small load, say 10k ? Measured directly at the card connector?

Message Edited by Henrik Volkers on 11-20-2009 11:36 AM