Honeywell XNX-UTAE Series User Manual

XNX Universal Transmitter
HART Protocol
179
HART Interface
The XNX Universal Transmitter is registered
with the HART Communication Foundation.
Note: The procedures in this section must be performed only by qualied
service personnel.
NOTE
!
All XNX transitters can communicate using the HART protocol
(dened at www.fieldcommgroup.org by the HART Communication
Foundation). HART is unique among eldbuses in that the digital
signal is superimposed on a traditional 4-20 mA current loop.
This provides the reliability of analog signaling with the advanced
diagnostic capability of a digital device.
Control System
or Other Host Application
Multiplexer
Barrier
Handheld Terminal
Field Device
Note: Instrument power is provided by an interface
or external power source that is not shown.
Figure 231. HART point-to-point mode
HART devices are usually connected as point-to-point networks.
The analog output of the transmitter can also be disabled to
facilitate construction of multidrop, all-digital HART networks.If
HART is not needed, the unit can be used as a 4-20 mA transmitter.
Since the transmitter is a slave, the internal modem will remain
silent if no master signal is present. Additionally the HART signal
is at too high a frequency (1200 Hz) to interfere with analog control
equipment. Another novel feature of HART networks is that two
masters can be present. The primary master is usually a distributed
control system (DCS), programmable logic controller (PLC), or a
personal computer (PC). The secondary master can be a handheld
terminal. The transmitter has been tested with the handheld
Emerson eld communicator.
Input/Output (I/O) System
Handheld Terminal
Field Devices
Control System or
Other Host Application
Note: Instrument power is provided by an interface
or external power source that is not shown.
Figure 232. HART multi-point mode
The XNX device descriptor (DD) le provides HART users with data
on the capabilities and features of the transmitter. Select HART
enabled devices are able to interface with XNX transmitters when

Honeywell XNX-UTAE Series Specifications

General

Brand	Honeywell
Model	XNX-UTAE Series
Category	Transmitter
Language	English