NI PXIe-4154, Manual

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30 | ni.com | NI PXIe-4154 Calibration Procedure
After the new coefficients are calculated, commit them to the hardware using the process
described in the
Considerations section.
Adjusting Output Resistance (Channel 0 Only)
To adjust the output resistance of a calibrated NI PXIe-4154, compare a set of requested output
resistance test points to measurements of the actual resistance at the output calculated using two
external DMMs and a precision shunt. Use an electronic load to control the output current. Refer
to Figure 7 for a connection diagram.
Refer to Table 25 for the resistance test points that you must request and measure for each range.
For example, Channel 0 requires the adjustment application to separately request 0
Ω , 0.5 Ω , and
0.9 Ω outputs from the NI PXIe-4154. Take measurements using the external DMMs and
precision shunt at each output resistance test point.
Note
After requesting a new output, wait one second to take a measurement with
the external DMMs to ensure the system has adequate time to settle.
Set the electronic load to an initial constant current of 100 mA. Obtain V
1
and I
1
by measuring
the voltage and calculating the current using the external DMMs and precision shunt.
Use the following steps to calculate the output resistance for each test point.
1.
Ensure that Remote Sense is ON.
2. Reconfigure the electronic load to a constant current of 1 A.
3. Obtain V
2
and I
2
. Measure the voltage and calculate the current using the external DMMs
and precision shunt.
4. Repeat steps 2 and 3 for each output resistance required adjustment point listed in Table 25.
5. Calculate the output resistance at each point using the following formula:
Output Resistance ( Ω ) = ( V
1
- V
2
) / ( I
2
- I
1
)
Note
Output resistance is requested on the NI PXIe-4154 using the NI DCPower
Property Node.
Table 24. NI-DCPower Cal Adjust Voltage Measurement VI Parameter Descriptions
Parameter Description
range The range to be adjusted with these settings.
reported outputs Array of measurements taken by the NI PXIe-4154 corresponding to required
adjustment test points in Table 23.
measured outputs Array of measurements taken by an external DMM corresponding to requested
outputs .
number of
measurements The number of elements in requested outputs and measured outputs .