©
National Instruments Corporation
5-33
VXI-SC-1102 User Manual
Chapter
5
Calibration
This chapter discusses the calibration procedures for the VXI-SC-1102.
Using the procedure described in this chapter, you will be able to
calculate the gain error and voltage offset on a per channel per gain
basis. You can store these constants in the onboard EEPROM for future
use and for automatic calibration when you are using National
Instruments software. The VXI-SC-1102 comes from the factory with
factory-determined calibration constants in the EEPROM. However,
National Instruments recommends that you recalibrate your
VXI-SC-1102 at least once per year or when you operate the submodule
outside the 20
°
to 30
°
C temperature range. If you are not using National
Instruments software to store the calibration data in the EEPROM, refer
to the VXI-SC-1102 Register-Level Programmer Manual for a more
detailed description of the EEPROM.
In order to calibrate the VXI-SC-1102, you will need to apply precision
voltages to the channel inputs and/or ground the channel inputs.
Calibration Equipment Requirements
According to standard practice, the equipment you use to calibrate the
VXI-SC-1102 should be 10 times as accurate as the VXI-SC-1102.
Calibration equipment with four times the accuracy of the
VXI-SC-1102 is generally considered acceptable. To calibrate the
VXI-SC-1102, you need a voltmeter with the following specifications:
•
Accuracy
±
6 ppm standard reading
±
15 ppm sufficient reading
•
Range
±
10 V
•
Resolution
8.5 digits
A multiranging 8.5-digit digital multimeter (DMM) can perform the
necessary calibrations.
To make sure that the DMM does not introduce an additional offset, you
can determine the offset error of the DMM by shorting its leads together
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