Programming instructions

Chapter 22 SCXI Calibration—Increasing Signal Measurement Precision
© National Instruments Corporation 22-3 LabVIEW Data Acquisition Basics Manual
The following sections explain how to calibrate your SCXI modules to
achieve the levels of accuracy that you desire.
Calibrating SCXI Modules
The SCXI Cal Constants VI in LabVIEW automatically calculates the
calibration constants for your module with the precision you need for your
particular application. You can find this VI in
Functions»DAQ»
Calibration and Configuration
. Refer to Chapter 29,
Calibration and
Configuration VIs
, in the
LabVIEW Function and VI Reference Manual
for
specifics on the SCXI Cal Constants VI and each of its parameters, or refer
to the LabVIEW
Online Reference
, by selecting
Help»Online
Reference…
.
By default, calibration constants for the SCXI-1102, SCXI-1122, and
SCXI-1141 are loaded from the module EEPROM. The SCXI-1141 has
only gain adjust constants in the EEPROM; it does not have the binary
zero offset. All other analog input modules (excluding the SCXI-1102,
SCXI-1122, and SCXI-1141) do not have calibration constants by default
and do not assume any binary offset and ideal gain settings. This means you
must use one of the procedures described in the
SCXI Calibration Methods
for Signal Acquisition
section to store calibration constants for your module
if it is not an SCXI-1102, SCXI-1122, or SCXI-1141.
You can determine calibration constants based specifically on your
application setup, which includes your type of DAQ device, your
DAQ device settings, and your cable assembly—all combined with your
SCXI module and its configuration settings.
Note
If your SCXI module has independent gains on each channel, the calibration
constants for each channel are stored at each gain setting.