Ams trex™ Device Communicator

Figure 4-19: Connection for controlling current
A. Analog input.
User Guide 
Loop Diagnostics application
September 2021
User Guide 
149

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2. On the Loop Diagnostics screen, tap 
Trex Unit Current
.
3. Tap one of the quick buttons to increase the current being supplied, use the up and
down arrow keys, or tap the pencil icon to enter a new value.
4. Verify the digital control system is reading the same current value.
4.11.4
Simulate a transmitter on an unpowered loop for a loop
check
The Trex unit can provide power and control current to simulate a device for a loop check.
In this setup, the control system is not providing power to the device. This task is used if
the loop will have a 4-wire transmitter.
The Trex unit supplies loop power from the HART + pwr terminals, and Loop Diagnostics
lets you control the current on the loop.
Procedure
1. Connect the lead set to the 
HART + pwr
terminals on the Trex unit and to the
unpowered loop.
Figure 4-20: Connection for providing power and simulating a transmitter
A. Analog input.
2. On the Loop Diagnostics screen, tap 
Trex Unit Power
.
3. Tap 
Simulate Transmitter with 4 mA
.
4. Change the current value by pressing the quick buttons or the up and down arrow
keys.
5. Verify the digital control system is reading the same current value.
Loop Diagnostics application
User Guide
September 2021
150
User Guide

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5
Fieldbus Diagnostics application
The Fieldbus Diagnostics application lets you run diagnostics to troubleshoot fieldbus
segments and devices. It provides power and basic communications for verifying device
operations on an isolated mini-segment. The application provides optional
communications for identifying the device list. You can connect the Trex unit at various
points along the fieldbus segment, so you can isolate the location of a problem.
The Fieldbus Diagnostics application can help you identify problems caused by loose wire
connections, water or moisture in cables or terminal housings, improper grounding, or
issues with fieldbus segment installations.
Note
The Fieldbus Diagnostics application can be used with the Device Communicator
communication module or Device Communicator Plus communication module. However,
the Trex unit cannot power a FOUNDATION fieldbus device with the Device
Communicator communication module. The application also requires a fieldbus license.
Measurements
The Fieldbus Diagnostics application lets you measure:
•
DC voltage: -34 to 34 volts
•
Noise: Low-frequency (870 Hz - 9 KHz), in-band frequency (9 KHz - 39 KHz), and high-
frequency noise (39 KHz - 100 KHz)
•
Fieldbus signal level: 100 - 1200 mV (peak-to-peak)