National Instruments VXI-SC-1102 - Manual (Page 32)

© National Instruments Corporation 5-1 VXI-SC-1102/B/C User Manual
Chapter
5
Calibration
This chapter discusses the calibration procedures for the
VXI-SC-1102/B/C submodules.
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/B/C submodules come from
the factory with factory-determined calibration constants in the
EEPROM. However, National Instruments recommends that you
recalibrate your VXI-SC-1102/B/C at least once per year or when you
operate the submodule outside the 20
°
to 30
°
C temperature range.
In order to calibrate the VXI-SC-1102/B/C, 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/B/C should be 10 times as accurate as the
VXI-SC-1102/B/C submodule itself. Calibration equipment with four
times the accuracy of the VXI-SC-1102/B/C is generally considered
acceptable. To calibrate the VXI-SC-1102/B/C submodules, 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