NI PXIe-4154, Manual

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NI PXIe-4154 Calibration Procedure | © National Instruments Corporation | 19
3. Calculate the current ( I
1
). Divide the voltage measured across the 100 m Ω precision shunt
by the characterized value of the 100 m Ω precision shunt.
4. Decrease the electronic load to Load Voltage 2, as shown in Table 9.
5. Record the DMM voltage at the and Output - terminals of the NI PXIe-4154 ( V
2
).
6. Calculate the current ( I
2
). Divide the voltage measured across the 100 m Ω precision shunt
by the characterized value of the 100 m Ω precision shunt.
7. Calculate the current change limit using the following formula:
Current Change Limit (A) = ±0.0001 * I Range * ( V
1
- V
2
).
8. Calculate the Current Change. Subtract I
1
from I
2
.
The test passes if the Current Change is less than or equal to the calculated Current Change Limit .
Remote Sense Accuracy Verification
To verify the remote sense accuracy of an NI PXIe-4154, use a test circuit of three resistors that
simulate voltage drop between the device and a load. Channels 0 and 1 should be tested
separately, using the same method. Remote sense accuracy validation should be performed only
after successfully validating the voltage and current measurement accuracy and the load
regulation.
Complete the following steps to verify remote sense.
1.
Ensure that Remote Sense is ON.
2. Connect a 22.6 Ω (R
1
), 200 Ω (R
2
), and 22.6 Ω (R
3
) resistor in series. The 200 Ω resistor is
the center resistor, as shown in Figure 8.
Figure 8. Remote Sense Output Verification Connection Diagram
Note Use separate twisted-pair cables for connections from and Output -
to the load and from Sense + and Sense - to the load. Refer to Figure 1 for a
connection diagram.
NI PXIe-4154
Sense –
Sense +
Output –
R3
R2
R1
22.6
Ω
200
Ω
22.6
Ω
Load
Voltage
HI Lead
Drop
DMM
Voltage
Mode
+
–
DMM
Voltage
Mode
+
–