Figure 11. Current Verification Connection Diagram
(Banana)
Triax to Banana/
Bare Wire
Precision
Shunt
LO
LOS
HI
HIS
DMM
Voltage
Mode
+
–
NI-DCPower Device
Sense LO
Sense HI
(Triax)
HI
(Triax)
LO
CHS GND
Shielded Combicon to
Banana/Bare Wire
(Banana)
2.
Set the
niDCPower Output Function
property or
NIDCPOWER_OUTPUT_FUNCTION
attribute to DC Current for the PXIe-4135.
3.
Set the first specified level range, limit range, and limit 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.
5.
Set the level on the PXIe-4135 to the first specified test point.
6.
Complete the following 4 steps within 5 minutes or less of completing the previous step
in order to ensure the internal device temperature remains stable.
7.
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
.
8.
Calculate the lower and upper current measurement test limits using the following
formula:
Current Measurement Test Limits
=
Test Point
± (|
Test Point
| *
% of Current
+
Offset
)
9.
Verify that the calculated
DMM Measured Current
value falls within the test limits.
10. If more than one test point per level range is specified, repeat the previous steps for each
test point, from setting the level to the test point on the PXIe-4135 up to this step.
11. If more than one level range is specified, repeat the previous steps using the values
specified in each level range.
12. Configure the PXIe-4135 output to disable.
22
|
ni.com
|
PXIe-4135 Calibration Procedure
