Ams trex™ Device Communicator

Optional internal resistors
250 Ohm or 500 Ohm resistor.
Current control
Range: 3-22.5 mA
Accuracy: 0.25% of span (4-20 mA)
Resolution: 0.04 mA
Drive capability: 650 ohms at 22.5 mA
HART + pwr terminals
(Includes HART power supply,
resistors, current control, and
ammeter)
The terminals enable HART communication with the Trex
unit, and provide power to one HART device in a bench
setup.
Connectors: Two banana plugs.
Voltage measurement accuracy: +/- 2% of reading for
measurements greater than 3 volts.
Internal resistor
167 Ohm resistor.
HART power supply
Power to a transmitter includes a 167 Ohm resistor and
high-accuracy ammeter.
Power to a positioner includes optional control of loop
current and "for reference only" ammeter reading.
Output:
22.9 V +/-0.2 V at no load.
16.4 V +/-0.3V at 22.5 mA.
Internal ammeter
The HART + pwr terminals have two ammeters: one for
connections to transmitters and one for connections to
positioners.
Accuracy: +/- .25 % of the reading.
Internal fuse rating: 50 mA.
Range: Up to 24 mA.
Ammeter resolution when powering a transmitter: 0.01
mA.
Ammeter resolution when powering a positioner: 0.1 mA.
Current control
Range: 3-22.5 mA
Accuracy: 0.25% of span (4-20 mA)
Resolution: 0.04 mA
Drive capability: 650 ohms at 22.5 mA
Technical specifications
User Guide
September 2021
184
User Guide

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Terminal
Overview
mA terminals (external ammeter)
The terminals measure current on a 4-20 mA current
loop.
Connectors: Two banana jack plugs.
Internal fuse rating: 250 mA.
Range: Up to 22.5 mA.
Resolution: 0.1 mA.
Shunt resistor: 2.43 Ohms.
FF terminals
The terminals enable FOUNDATION fieldbus
communication with the Trex unit.
Voltage measurement accuracy: +/- 3% of reading for
measurements greater than 3 volts.
FF+ pwr terminal
(Includes power supply, power
conditioning, and two terminators)
The terminal provides power to one FOUNDATION
fieldbus device in a bench setup.
Connector: One banana jack plug.
Voltage measurement accuracy: +/- 3% of reading.