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Table 11.
1 A and 3 A Current Output and Measurement Adjustment
Level Range
Limit Range and Limit
Shunt
Test Point
1 A
6 V
1 Ω
1 A
-1 A
3 A
6 V
333 mΩ
3 A
-3 A
1.
Make the necessary connections for this procedure, as shown in the following figure.
Figure 11.
Current Output and Measurement Adjustment Connection Diagram
NI-DCPower Device
Sense LO
Sense HI
HI
LO
+
–
Precision
Shunt
DMM
Voltage
Mode
2.
Set the niDCPower Output Function property or NIDCPOWER_OUTPUT_FUNCTION
attribute to DC Current for the NI 4138.
3.
Set the first specified level range, limit range, and limit on the NI 4138.
4.
Set the level on the NI 4138 to the first specified test point.
5.
Calculate the current through the shunt by completing the following steps.
a)
Take a voltage measurement across the shunt using the DMM.
b)
Divide the voltage measurement by the calibrated value of the shunt.
6.
Store the value from the previous step as input for the niDCPower Cal Adjust VI or
function called in the following steps.
7.
Repeat the previous steps, from setting the level to the test point on the NI 4138 up to this
step, for each specified test point in the level range.
8.
Update the output calibration constants by configuring and calling the niDCPower Cal
Adjust Current Limit or niDCPower_CalAdjustCurrentLimit function.
a)
Input the DMM measurements as the measured outputs.
b)
Input the test points as the requested outputs.
c)
Input the specified level range as the range.
9.
If more than one level range is specified, repeat the previous steps using the values
specified in each level range.
NI PXIe-4138 Calibration Procedure
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© National Instruments
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