Calibration - National Instruments PCI-1200 User Manual

Calibration

© National Instruments Corporation
This chapter discusses the calibration procedures for the NI PCI-1200
analog I/O circuitry. However, the NI PCI-1200 is factory calibrated, and
NI can recalibrate the device if needed. To maintain the 12-bit accuracy of
the NI PCI-1200 AI and AO circuitry, recalibrate at six-month intervals.
There are four ways to perform calibrations.
• If you have LabVIEW, use the 1200 Calibrate VI. This VI is located in
the Calibration and Configuration palette.
• If you have LabWindows/CVI, use the
• If you do not have LabVIEW or LabWindows/CVI, use the NI-DAQ
Calibrate_1200
• Use your own register-level writes to the calibration DACs and the
EEPROM. (Use this method only if NI-DAQ does not support your
operating system.)
To calibrate using register-level writes, you need to use the NI PCI-1200
Register-Level Programmer Manual.
The NI PCI-1200 is software calibrated. The calibration process involves
reading offset and gain errors from the AI and AO data areas and writing
values to the appropriate calibration DACs to null the errors. There are four
calibration DACs associated with the AI circuitry and four calibration
DACs associated with the AO circuitry. After the calibration process is
complete, each calibration DAC is at a known value. Because these values
are lost when the device is powered down, they are also stored in the
onboard EEPROM for future reference.
The factory information occupies one half of the EEPROM and is
write-protected. The lower half of the EEPROM contains four user areas
for calibration data.
When the NI PCI-1200 is powered on, or the conditions under which it is
operating change, you must load the calibration DACs with the appropriate
calibration constants.
Calibrate_1200
function.
5-1
5
function.
NI PCI-1200 User Manual