Table 7. 1 µA and 10 µA Current Output and Measurement Verification
Level
Range
Limit
Range and
Limit
Shunt
Test
Point
As-Found
Measurement Test
Limit (% of C
Offset)
As-Left
Measurement Test
Limit (% of C
Offset)
6 V
1 µA
1 MΩ
-0.9 V
0.022% + 40 pA
0.0071% + 17 pA
0.9 V
20 V
10 µA
-9 V
0.022% + 300 pA
0.0071% + 130 pA
9 V
1.
Make the necessary connections for this procedure, as shown in the following figure:
Figure 6. Current Connection Diagram, Part 1
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 Voltage for the PXIe-4137.
3.
Set the first specified level range, limit range, and limit on the PXIe-4137.
4.
Measure the internal device temperature and perform self-calibration if necessary.
a)
If the internal device temperature exceeds T
cal
±1 °C, wait up to five minutes for the
temperature to stabilize to within T
cal
±1 °C.
b)
If after five minutes the stable temperature still exceeds T
cal
±1 °C, call the self-
calibration VI or function.
5.
Set the level on the PXIe-4137 to the first specified test point.
Complete the following four steps within 5 minutes or less of completing step 4 in order
to ensure the internal device temperature remains stable.
6.
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.
c)
Record the calculated value as
DMM Measured Current
.
14
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NI PXIe-4137 Calibration Procedure
