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NI PXIe-4339 Calibration Procedure
e.
Configure the voltage channels to connect to the paired channels excitation voltage
using the following parameters:
Property Node
: DAQmx channel
reference
: <task_out> from the previous step
ActiveChans
: Channels used in step 11d
AI.InputSrc
: _paired_channel_excitation
f.
Start the task.
g.
Average the ratiometric readings and excitation channel voltage measurements that
you acquired.
h.
Scale the averaged excitation channel voltage measurements using the ratio
verification adjustment factor and the formula provided in step 9. Record this value in
Table 8 as
Vm_ex_ch
#
where
#
is the channel number corresponding to the
ratiometric channel being verified.
i.
Calculate the ratiometric reference input value for each ratiometric channel by
dividing the calibrator output voltage setting by the paired channels ratio verification
adjusted excitation voltage measurement,
Vm_ex_ch#
, from step h, record this value
as the
Test Point
value in Table 8.
j.
Use the equations shown in Table 8 to calculate the high limit and low limit using the
Test Point value recorded in the previous step.
k.
For each channel, compare the averaged ratiometric (V/V) measurement to the high
and low limit values from Table 8. If the result is between these values, the device
passes the test.
Table 7.
Voltage Mode Parameters
Configuration
Value
Channel Name
Dev1/ai1,ai3,ai5,ai7
(These are the paired channels of the V/V
channels that are being verified.)
Task
AI Voltage
Task Out
<task_out>
Sample Mode
Finite number of samples
Sample Clock Rate
100
Samples Per Channel
100
Maximum Value
10
Minimum Value
-10
Units
Volts
