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NI 9242 User Manual and Specifications
•
Connect the Neutral terminal of the NI 9242 as close as
possible to the isolated ground of the potential transformer.
•
Use the L-N voltage measurements the NI 9242 returns as the
default value.
Tip
You can convert L-N voltage measurements to
channel-to-earth ground by adding the Neutral terminal
measurement to each of the AI channels.
Converting L-N Measurements to L-L
To convert L-N measurements to L-L values, calculate the voltage
difference between the AI channels using your application
software.
Refer to the following equation for an example of converting L-N
measurements to L-L.
Phase A to Phase B Voltage
=
AI0
-
AI1
where
AI0
is the reading from Phase A
AI1
is the reading from Phase B