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National Instruments Corporation
6-1
6
Calibration
This chapter discusses the calibration procedures for the SCXI-1104/C
module.
Overview
Using the procedure described in this chapter, you can calculate the gain
error and voltage offset on a per channel 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 module
comes from the factory with factory-determined calibration constants in the
EEPROM. However, it is recommended that you recalibrate a module at
least once per year or when you operate the module outside of the 20–30
°
C
temperature range.
To calibrate the SCXI-1104/C module, you need to apply precision
voltages to the channel inputs and/or ground the channel inputs.
Calibration Procedure
This section describes the calibration equipment requirements and explains
how to calibrate the offset and gain on the SCXI-1104/C module.
Calibration Equipment Requirements
According to standard practice, the equipment you use to calibrate the
SCXI-1104/C module should be ten times as accurate as the SCXI-1104/C
module. Calibration equipment with four times the accuracy of the
SCXI-1104/C is generally considered acceptable.
To calibrate the SCXI-1104/C module, you need a voltmeter with the
following specifications:
•
Accuracy
±
6 ppm standard reading
±
15 ppm sufficient reading
•
Resolution
8.5 digits
