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Chapter 2 Function Reference — SCXI_Calibrate_Setup
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National Instruments Corporation 2-331 NI-DAQ FRM for PC Compatibles
4. Acquire data using the DAQ functions; you should acquire and average many samples.
If you have enabled the filter on the module, wait for the amplifier to settle after
calling
SCXI_Calibrate_Setup
before you acquire data. Refer to your SCXI-1100,
SCXI-1122, or SCXI-1141 user manuals for settling times caused by filter settings.
5.
SCXI_Calibrate_Setup
—Disable calibration.
6. Continue with your application. Whenever you acquire samples from the module at the
gain that you chose in step 2, subtract the binary offset that you read in step 4 from each
sample before scaling the data, or call
SCXI_Cal_Constants
to store the offset in
NI-DAQ memory or the EEPROM. Then, subsequent calls to
SCXI_Scale
for the given
gain will automatically subtract the offset for you. Refer to the
SCXI_Cal_Constants
function for more information.
Refer to your SCXI-1321 or SCXI-1122 user manuals for information about how the module
applies the shunt resistor when calOp = 2.
The SCXI-1141 has a separate amplifier for each channel, so you will have to repeat the above
procedure for each channel you wish to calibrate.