Emerson AMS Trex User Manual page 140

Loop Diagnostics application
Figure 4-6:
The Trex unit measures both voltage and current from the HART + pwr terminals.
Figure 4-7:
The Trex unit measures voltage from the HART terminals. Voltage measurements can be taken at various
points to identify voltage drops along the loop.
A.
132
Power and control current to a positioner
Connect to an externally-powered positioner in-parallel
Current source
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