National Instruments PXIe-4480, Calibration Procedure, Page: 24 / 34

24 | ni.com | NI PXIe-4480//4481 Calibration Procedure
18. Configure the calibrator to output a 6.3 V
rms
signal at 1 kHz.
19. Call
DAQmxSetup4480Calibration
using the following parameters:
calHandle :
myCalHandle
physical channels :
0
cal mode :
DAQmx_Val_Charge
Note
Set the physical channels parameter to the channel of the device being
calibrated, where 0, for example, represents channel 0.
20. Call
DAQmxAdjustDSAAICalWithGainAndCoupling
(DAQmx Adjust DSA AI
Calibration With Gain and Coupling VI from the DAQmx Adjust DSA AI Calibration
Polymorphic VI), using the following parameters:
calHandle :
myCalHandle
coupling :
DAQmx_Val_AC
gain :
6
referenceVoltage : Calculated input charge value
The calculated input charge value is the product of the value of the calibration capacitor
and the calibrator output value (that is, Q = C * V). The capacitor value may be obtained
from its calibration certificate or from the sticker applied to its housing body. For example,
for a capacitor value of 1001 pF and a calibrator voltage of 6.3 V, the calculated input
charge value in Coulombs is 6306.3e-12.
21. Repeat steps 17 through 20 for each input channel, changing the cable connections
accordingly and substituting the physical channels parameter with the channel being
calibrated.
Committal
22. Call
DAQmxCloseExtCal
(DAQmx Close External Calibration VI) with the following
parameters to finish the calibration adjustment:
calHandle:
myCalHandle
action:
DAQmx_Val_Action_Commit
or
DAQmx_Val_Action_Cancel
Use the action
cancel
if there has been any error during the calibration or if you do not
want to save the new calibration constants in the device EEPROM.
Use the action
commit
if you want to save the new calibration constants in the device
EEPROM.
The device is now calibrated with respect to the external sources.