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self calibration of PCI-6259

Hello,

I have a PCI-6259 board which is due for calibration, according to the recommended NI schedule; however I was wanting to assess the degree of accuracy loss which the board has incurred over its use thus far.  My question is whether the reference voltage and the voltage values read at the various gain settings, during the self-calibration in Measurement and Automation, can be displayed.  I was hoping to use this information to determine if the board is still functioning at the level accuracy I require, before sending the board to be calibrated externally. 
I would greatly appreciate any information regarding this, or any other methods which could yield similar information regarding the state of the board (with respect to the deviation from the original calibrated accuracy).

Thank you very much,
Karin

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Karin,

To verify calibration, or re-calibrate, please see this document. The verification steps start on page 7. Information about calibration from National Instruments can be found at http://www.ni.com/support/calibrat/

David L.
Systems Engineering
National Instruments
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Hello David,
 
Thank you very much for your reply.  I forgot to mention in my original post that I had infact read through that calibration procedure; unfortunately, we do not have all of the equipment necessary, including the calibrator.  Is there any other way to verify the results (i.e. the voltages wrt the reference voltage) of the self-calibration?
 
Thank you once again for your reply,
Karin
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Karin,

The document you have looked at is the best reference I can give. After this, I would suggest sending it in for calibration if you are receiving bad measurements.

David L.
Systems Engineering
National Instruments
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Karin,

You can not tell how accurately the PCI-6259 is measuring with using external equipment (as described in the calibration procedure). The ADC on the board can read the calibration reference. But if this reading has changed, you can not tell whether the reference has drifted, or the measurement circuitry itself has drifted. The calibration algorithms on the board always assume that the reference has not drifted. So, if the measurement circuity has drifted, the process of self-calibrating the board corrects for this drift. But if the reference has drifted, the board can not detect this.

Since you can not distinguish between the two cases, knowing the value of the reference measured by the board does not help you know how accurate your board is measuring. You have to measure a stable external device (such as a calibrator) to detect if the on board reference has drifted.
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