Ams trex™ Device Communicator

Procedure
1. Tap the image of the terminals on the 
Loop Diagnostics
screen.
A larger image is displayed.
2. Tap 
OK
to close the full-screen view, and return to the 
Loop Diagnostics
screen.
4.3
Powering transmitters or positioners from
Loop Diagnostics
The 
Trex Unit Power
option in the Loop Diagnostics application enables the Trex unit to
power one transmitter or positioner in a bench setup. This lets you isolate a problematic
device from its HART loop and verify its operation, or perform wiring continuity checks on
cables where no power exists.
Use the HART + pwr terminals on the Trex unit to connect to the transmitter or positioner.
When you tap the Trex Unit Power option, you can select the type of device (transmitter or
positioner) to power.
The Trex unit notifies you if it measures voltage at the HART + pwr terminals when you try
to turn on 
Trex Unit Power
. If the measured voltage is less than 8 volts, the Loop
Diagnostics application assumes that the voltage may be from the device, and you can
select to ignore the low voltage and provide power from the Trex unit. If the voltage is
greater than or equal to 8 volts, the Loop Diagnostics application will not let you enable
Trex Unit Power
to power a device.
The 
Trex Unit Power
immediately turns off if the Loop Diagnostics application detects one
of the following:
•
A short circuit.
•
The lead set is no longer connected to the device.
•
A very high device-load that exceeds the capacity of the 
Trex Unit Power
option.
Loop Diagnostics application
User Guide
September 2021
130
User Guide

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Figure 4-3: Select the type of device to power