User`s guide

Calibration
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5
Calibration
This chapter introduces the calibration process to minimize AD meas-
urement errors.
5.1 Loading Calibration Constants
The DAQ-2213/2214 is factory calibrated before shipment by writing the
associated calibration constants of TrimDACs to the on-board EEPROM.
TrimDACs are devices containing multiple DACs within a single package.
TrimDACs do not have memory capability. That means the calibration
constants do not retain their values after the system power is turned off.
Loading calibration constants is the process of loading the values of
TrimDACs stored in the on-board EEPROM. ADLINK provides software to
make it easy to read the calibration constants automatically when neces-
sary.
There is a dedicated space for calibration constants in the EEPROM. In
addition to the default bank of factory calibration constants, there are three
extra user-modifiable banks. Users can load the TrimDACs values either
from the original factory calibration or from a calibration that is subse-
quently performed.
Because of the fact that errors in measurements and outputs will vary with
time and temperature, it is recommended re-calibration when the card is
installed in the users’ environment. The auto-calibration function used to
minimize errors will be introduced in the next sub-section.