Ams trex™ Device Communicator

Figure 3-50: Gauge chart
3.26.7
Graphs
A graph is a snapshot line drawing of device information. Use the drop-down list to select
the variable you want to highlight. Additional variables may be present if more than one is
defined for the option selected in the drop-down list.
The selected variable from the drop-down list appears as a bold, solid-colored line while
the other variables with the same Y-axis appear as thin colored lines. The colors displayed
are determined by the device description and may vary between devices. The labels and
axis displayed are determined by the device manufacturer.
You may also see symbols such as circles on some variables. These show keypoints that
indicate the important values on a graph. If more than seven variables are on the graph,
“+” symbols are displayed for the keypoints.
Field Communicator application
User Guide
September 2021
122
User Guide

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Figure 3-51: Graph
3.27
Disconnect a device
Prerequisites
Before you disconnect the Trex unit from a device, resolve any unsent data to the device.
Procedure
Tap 
Menu
→
Disconnect
or remove the lead set from the device or the Trex unit.
The Trex unit detects the loss of voltage or current and stops communicating with the
device. If the Trex unit was powering the device, the Trex unit stops providing power when
the lead set is removed. The 
Connect - Select
screen is displayed.
User Guide 
Field Communicator application
September 2021
User Guide 
123

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Field Communicator application
User Guide
September 2021
124
User Guide

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4
Loop Diagnostics application
The Loop Diagnostics application helps you troubleshoot the wiring of a 4-20 mA current
loop by measuring the voltage and the current. The application can also power a
transmitter or positioner to isolate the device from its current loop and to verify its
operation.
Note
The Trex unit needs the Device Communicator Plus communication module to use the
Loop Diagnostics application. You may also need a second lead set.
If you connect the Trex unit's HART terminals in series with an externally-powered loop,
you can enable 
Trex Unit Current
and have the Trex unit control current (similar to how a
transmitter controls current). Controlling current lets you do the following:
•
Verify the input module on a digital control system.
•
Verify the cabling between the connection point and the input module on a digital
control system.
•
Move a positioner.
If the Trex unit is not connected to an externally-powered loop, you can enable 
Trex Unit
Power
to power one transmitter or positioner. This helps you isolate a problematic device
from its current loop and verify its operation. Powering a device lets you do the following:
•
Verify a transmitter in isolation by powering the device and measuring the output.
•
Verify a positioner in isolation by powering and moving the positioner.
•
Perform wiring continuity checks on cables where no power exists.