small offset in voltage reading

[Wendy]

The voltage readings from my labview program is 3mV different than that of the amplifer meter. How can I adjust for this difference. Thanks

[tbob]

That should never be. Are you taking a single reading? If not, you may read one value in Labview, and then a fraction of a second later the instrument takes another reading which is different from the one Labview captured. In that case, maybe you are not giving your signal enough time to settle before you take the reading. You normally need to wait some small time between turning on a voltage source or closing a switch and taking the voltage reading.

[Wendy]

Well, I'm doing voltage clamp recordings and taking voltage and current signals. The readings I get are exactly 3mV off. For example if my holding command was -55mV, Labviews reads -58mV and so on. Same goes for the current data. The readings on the oscilloscope is same as that of my amplifier.
Is there a output offset that I need to specify or somehow substract the voltage and current offset from the output.
Thanks

[tbob]

Labview does not introduce any offset or anything like that. It displays exactly what it gets from the instrument. How are you getting the reading, GPIB or serial? What do you mean by a holding command? What kind of instrument, maker and model? Somehow, the reading the instrument displays and the reading it sends to Labview is different. Are you using DBL in Labview to display the results? Maybe you could post an example of part of your code that reads and displays the reading. What version of Labview?

[Yorametz]

Hello,

I'm just raising a patch clamp system and has a conventional amplifier

(A-M systems, Model 2400).

I would like to use an NI board and Labview to aquire and anlyze the data.

Any chance I can use an existing system instead of developing my own application?

[Dennis_Knutson]

There is no driver available for that instrument on the Instrument Driver Network. On that page is a link to request one. You can also use the Instrument I/O Assistant.

p.s. You should really post a new question instead of replying to an old and unrelated thread.