National Instruments RM-4339, Calibration Procedure

Page: 10 / 13

10 | ni.com | RM-4339 Calibration Procedure
6. Acquire an AI Bridge (V/V) measurement with shunt calibration disabled.
a.
Create and configure an AI Bridge (V/V) channel according to the values found in
Table 6.
b. Disable the SCB shunt calibration circuit using the following parameters:
Property Node: DAQmx Channel
AI.Bridge.ShuntCal.Enable: False
c. Commit the task by calling DAQmx Control Task with the following parameter:
Action: Commit
d. Wait 5 seconds to allow the circuitry to stabilize. If the calibrator requires more than
a 5 second wait time, use the wait time required by the calibrator.
e. Start the task by calling DAQmx Start Task.
f. Average the readings that you acquired and record the values as Result
SCD
.
g. Clear the task by calling DAQmx Clear Task.
7. Acquire an AI Bridge (V/V) measurement with shunt calibration enabled.
a.
Create a task.
b. Create and configure an AI Bridge (V/V) channel according to the values found in
Table 6.
Table 6. AI Bridge (V/V) Mode Setup
Configuration Value
Channel Name
Dev1/aix
, where
x
refers to the channel number
Measurement Type AI Bridge (V/V)
Bridge Configuration Quarter
Nominal Bridge Resistance 120 Ω , 350 Ω , 1000 Ω

Voltage Excitation Source Internal
Voltage Excitation Value 3.3 V for 120 Ω configuration, 5 V for 350 Ω and 1 k Ω
configurations
Maximum Value 0.01
Minimum Value -0.01
Units V/V
Sample Mode Finite Samples
Sample Clock Rate 100
Samples per Channel 100
*
Use the bridge resistance value that corresponds to the configuration being verified.