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Chapter 3
Using the NI PXI-4204
3-24
ni.com
2.
Display the list of devices and interfaces by clicking the
+
next to the
Devices and Interfaces
icon.
3.
Display the list of NI-DAQmx devices by clicking the
+
next to
NI-DAQmx Devices
icon.
4.
Right-click the NI PXI-4204 and select
Self-Calibrate
.
5.
A dialog box appears indicating that the NI PXI-4204 is
self-calibrating.
6.
When the dialog box disappears, the NI PXI-4204 is successfully
self-calibrated.
Note
The NI PXI-4204 also can be self-calibrated programmatically by using
DAQmx
Self Calibrate.vi
in LabVIEW.
The results of an internal calibration are stored in the NI PXI-4204 flash
memory so that the CalDACs are automatically loaded with the newly
calculated calibration constants the next time the NI PXI-4204 is
powered on.
Performing a self-calibration at the operating temperature of your
application will ensure the NI PXI-4204 meets the specifications in
Appendix A,
External Calibration
The NI PXI-4204 has an onboard calibration reference for the DAQ
circuitry and the signal conditioning circuitry to ensure the accuracy
of self-calibration. The specifications are listed in Appendix A,
. The reference voltages are measured at the factory and
stored for subsequent internal calibrations. The voltages are stable enough
for most applications, but if you are using the device at an extreme
temperature or if the onboard references have not been measured for a year
or more, you may want to externally calibrate the device.
NI recommends
an external calibration of the NI PXI-4204 once a year.
An external calibration refers to calibrating the device with a known
external reference rather than relying on the onboard references. During the
external calibration process, the onboard reference values are re-calculated.
This compensates for any time or temperature drift related errors in the
onboard references, which may have resulted since the last calibration.
You can save the results of the external calibration process so that the
new calibration constants are automatically loaded the next time the
NI PXI-4204 is powered on. The NI PXI-4204 then uses the newly
measured onboard references for subsequent internal calibrations.