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National Instruments Corporation
57
NI 5421/5441 Calibration Procedure
30. Wait 500 ms for the output to settle.
31. Use the DMM to measure the NI 5421/5441 voltage output directly
into the DMM (into a high-impedance load). This measurement is
external measurement 1
, which is used in step 32.
32. Call
niFgen_CalAdjustCalADC
(niFgen Cal Adjust Cal ADC VI)
using the following parameters:
•
vi
: The session handle returned from
niFgen_InitExtCal
•
voltagesMeasuredExternally
: An array containing two
elements—the two voltages (
external measurement 0
,
external measurement 1
) that you measured with the
DMM—in the order that you measured them.
•
voltagesMeasuredWithCalADC
: An array containing two
elements—the two voltages (
cal ADC measurement 0
,
cal ADC measurement 1
) that you measured with the onboard
calibration ADC—in the order that you measured them.
33. Call
niFgen_SetAttributeViBoolean
to disable the analog
output (niFgen property node:
Basic Operation»Output Enabled
)
using the following parameters:
•
vi
: The session handle returned from
niFgen_InitExtCal
•
channelName
:
"0"
•
attributeID
:
NIFGEN_ATTR_OUTPUT_ENABLED
•
value
:
VI_FALSE
34. Call
niFgen_SetAttributeViInt32
to set the calibration ADC
input (niFgen property node:
Calibration»Cal ADC Input
) using
the following parameters:
•
vi
: The session handle returned from
niFgen_InitExtCal
•
channelName
:
""
(empty string)
•
attributeID
:
NIFGEN_ATTR_CAL_ADC_INPUT
•
value
:
NIFGEN_VAL_GROUND
35. Call
niFgen_Commit
(niFgen Commit VI) to commit the attribute
values to the device using the following parameter:
•
vi
: The session handle returned from
niFgen_InitExtCal
Closing the External Adjustment Session
When you have completed all the adjustment stages, you must close the
external adjustment session to store the new calibration constants in the
onboard EEPROM.
