Verifying 10 nA Current Measurement and Output
Compare a set of measured currents reported by the PXIe-4135 to the currents measured by a
DMM.
Complete this procedure only after successfully completing all previous verification
procedures. Verify level ranges in the order listed in the table.
Refer to the following table as you complete the following steps:
Table 9. 10 nA Current Output and Measurement Verification
Level
Range
Limit
Range
and
Limit
(Part 1)
Limit
Range
and
Limit
(Part 2)
Shunt
Test
Point
As-Found
Measurement
Test Limit (% of
C Offset)
As-Left
Measurement
Test Limit (% of
C Offset)
6 V
1 mA
10 nA
100 MΩ -0.9 V
0.05% + 5 pA
0.021% + 1 pA
0.9 V
1.
Make the necessary connections for this procedure, as shown in the following figure:
Figure 6. Current Connection Diagram, Part 1
Triax Cable
Triax to Bare Wire
Precision
Shunt
LO
LOS
HI
(T
riax)
HIS
(T
riax)
NI-DCPower Device
Sense LO
Sense HI
(Triax)
HI
(Triax)
LO
CHS GND
Shielded Combicon to
Banana/Bare Wire
DMM
Voltage
Mode
+
–
2.
Set the
niDCPower Output Function
property or
NIDCPOWER_OUTPUT_FUNCTION
attribute to DC Voltage for the PXIe-4135.
3.
Set the specified level range, limit range (part 1), and limit (part 1) on the PXIe-4135.
4.
Measure the internal device temperature and perform self-calibration if necessary.
a)
After measuring the internal device temperature, wait for the internal device
temperature to stabilize. Temperature is considered stable when it has not changed
by more than ±1 °C in the previous 5 minutes.
b)
After the internal temperature has stabilized, if the temperature still exceeds
T
cal
± 1 °C, call the self-calibration VI or function.
16
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PXIe-4135 Calibration Procedure
