Page 19
The maximum allowed value for NPLC equates to two minutes: 7.2 k at 60 hertz or 6 k at 50 hertz. With
NPLC set to 0, the tester will take a very fast measurement with no averaging.
Measurement Low Limit
If desired you can enable a measurement low resistance limit. If the measured resistance is below the
measurement low limit, the custom instruction will fail.
Measurement High Limit
If desired you can enable a measurement high resistance limit. If the measured resistance is above the
measurement high limit, the custom instruction will fail.
Tare Value
Since 4-wire fixturing accurately removes the effect of fixturing resistance, use this setting to subtract
resistance in that portion of the fixturing that is not 4-wire.
For more information see Fixture Tare Values in Easy-Wire help.
Forward and Reverse 2W Resistance
The Forward and Reverse 2W Resistance custom instruction can be used to eliminate thermal couple
effects from resistance measurements. This custom instruction is similar to the Compliance Limited 2W
Resistance custom instruction, which allows the CH2 tester to apply a fixed source current and sense the
resulting voltage drop to calculate the DUT resistance. The Forward and Reverse 2W Resistance custom
instruction differs in that the tester applies the source current in both the forward and reverse direction,
measures the resistance in both scenarios, and then averages these two measurements to return one
resistance measurement.
Cable assemblies may have connections with dissimilar metals that cause minor thermocouple effects.
When the tester applies a source current to make these measurement, the voltage that is measured to
compute resistances in the DUT may include up to a few millivolts from thermoelectric effects.
Thermoelectric voltage errors are averaged out using this instruction. Therefore, use this instruction to
obtain the most accurate and repeatable resistance measurement possible with the Cirris CH2 tester.
See also the Compliance Limited 4W Resistance on page 18 for a description of the parameters for this
test instruction.
To Next Page
