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Why Is The Residual Offset So Large After I Perform A Null Correction On A Channel Of My SCXI-1520?

Primary Software: Driver Software>>NI-DAQ
Primary Software Version: 4.6.1
Primary Software Fixed Version: N/A
Secondary Software: N/A

Problem:
I am trying to perform an offset null correction on a channel of my SCXI-1520. Whenever I perform the null correction, I have a very large offset voltage that is on the order of millivolts. I am looking for an offset on the order of microvolts.

Solution:
There are several possible sources for a large offset after a null correction. First, check the quarter bridge completion resistor. If you are using the quarter bridge completion resistor that is socketed in the SCXI-1314 terminal block, make sure that the bridge completion resistance matches the nominal resistance of your strain gauge.

If you are using a virtual channel in Measurement & Automation Explorer (MAX), make sure that the bridge setting in the SCXI-1520 properties window matches the bridge setting of your virtual channel. For example, if you have created a half bridge virtual channel (Type I, II, or III) on channel 1, then make sure that the property window for that module has channel 1 set to half bridge configuration. Please refer to the manuals and example below for more information.

Related Links:
Product Manuals
Developer Zone Example Program: Manual Strain-Null Calibration with File Output
KnowledgeBase 2EIEIJUJ: Why Do My Measurements Not Change When I Engage the Shunt Calibration Circuits on My SCXI-1520?

Attachments:

 






Report Date: 11/19/2001
Last Updated: 09/17/2007
Document ID: 2FIF86UJ

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