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Calibration
5.2
Auto-calibration
By using the auto-calibration feature of the DAQ/PXI-20XX, the calibration
software can measure and correct almost all the calibration errors without
any external signal connections, reference voltages, or measurement de-
vices.
The DAQ/PXI-20XX has an on-board calibration reference to ensure the
accuracy of auto-calibration. The reference voltage is measured at the
factory and adjusted through a digital potentiometer by using an ul-
tra-precision calibrator. The impedance of the digital potentiometer is
memorized after this adjustment. It is not recommended for users to adjust
the on-board calibration reference except when an ultra-precision cali-
brator is available.
Note:
1.
Before auto-calibration procedure starts, it is recommended to
warn up the card for at least 15 minutes.
2.
Please remove the cable before an auto-calibration procedure is
initiated because the DA outputs would be changed in the process
of calibration.
5.3
Saving Calibration Constants
After an auto-calibration is completed, users can save the new calibration
constants into one of the three user-modifiable banks in the EEPROM. The
date and the temperature when you ran the auto -calibration will be saved
accompanied with the calibration constants. This means users can store
three sets of calibration constants according to three different environ-
ments and re-load the calibration constants later.
