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National Instruments Corporation
5-1
5
Calibration
This chapter discusses the calibration procedure for the device.
Calibration is the process of minimizing measurement and output voltage
errors by making small circuit adjustments. On the NI 6052E, these
adjustments take the form of writing values to onboard calibration DACs
(CalDACs). NI-DAQ includes calibration functions for performing all the
steps in the calibration process.
Some form of device calibration is required for most applications. If you do
not calibrate the device, the signals and measurements could have large
offset, gain, and linearity errors.
Three available levels of calibration are described in this chapter. The first
level,
, is the fastest, easiest, and least
accurate. The last level,
, is the slowest, most difficult,
and most accurate. Choose a level according to the demands of your
application.
Loading Calibration Constants
Before shipment, the device is factory-calibrated at approximately 25 °C
to the levels indicated in Appendix A,
. The associated
calibration constants—the values written to the CalDACs to achieve
calibration in the factory—are stored in the onboard nonvolatile memory
(EEPROM). Because the CalDACs have no memory capability, they do not
retain calibration information when the device is unpowered. Loading
calibration constants is the process of loading the CalDACs with the values
stored in the EEPROM. NI-DAQ determines when this is necessary and
automatically loads calibration constants. If you are not using NI-DAQ,
you must load these values.
In the EEPROM there is a user-modifiable calibration area in addition to
the permanent factory calibration area. You can load the CalDACs with
values either from the original factory calibration or from a calibration that
you subsequently performed.
