Emerson AMS Trex User Manual page 193

Terminal
HART + pwr terminals
(Includes HART power supply,
resistors, current control, and
ammeter)
mA terminals (external ammeter)
FF terminals
User Guide
Overview
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
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.
The terminals enable FOUNDATION fieldbus
communication with the Trex unit.
Voltage measurement accuracy: +/- 3% of reading for
measurements greater than 3 volts.
Technical specifications
185