Ams trex™ Device Communicator

Communication module
A term to refer to either the Device Communicator communication module or the Device
Communicator Plus communication module.
Data Link Time
A network-wide time that is periodically distributed by the LAS to synchronize all device
clocks on the bus.
Device
See HART device or FOUNDATION fieldbus device.
Device Communicator communication module
A communication module you can attach to the Trex unit. This module has terminals that
enable the Trex unit to communicate with HART and FOUNDATION fieldbus devices.
Device Communicator Plus communication module
A communication module you can attach to the Trex unit. This module has terminals that
enable the Trex unit to communicate with HART and FOUNDATION fieldbus devices,
power a HART or FOUNDATION fieldbus device, and measure current on a 4-20 mA
current loop.
Device description (DD)
A set of instructions written in the HART or FOUNDATION fieldbus Device Description
Language that defines the parameters, commands, and methods that a host application
uses to communicate with a HART or FOUNDATION fieldbus device.
Externally-powered device
A HART or FOUNDATION fieldbus device that is powered by a power supply or digital
control system. The Trex unit is not powering the device, loop, or fieldbus segment.
Externally-powered loop
User Guide 
Glossary
September 2021
User Guide 
193

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A HART or 4-20 mA current loop that is powered by a power-supply or digital control
system. The Trex unit is not powering the loop.
FOUNDATION fieldbus
FOUNDATION fieldbus technology uses device descriptions and function blocks to enable
intelligent devices to execute control functions traditionally performed by a distributed
control system.