Figure 4-12:
The Trex unit measures current from the mA terminals on an externally-powered loop without breaking
the loop and connecting the ammeter (mA terminals) in-series.
WARNING!
Do not insert a resistor in parallel with either the HART + pwr or HART terminals on the Trex unit, or
in parallel with the device's communication terminals. This will interfere with the current
measurements.
Note
Please review your device documentation for additional information about reading current from the test
terminals. The orientation of the terminals on your device may be different. The drawing below is an
example.
A.
User Guide
Measure current from an externally-powered transmitter device with
test terminals
Voltage source
Loop Diagnostics application
135