Options ������������������������������������������������������������������������������������� 56 Path Length; Local Hart Interface; Point-To-Point Mode - Honeywell XNX-AM Series Technical Manual

XNX Universal Transmitter
Options

Local HART Interface

Available with any sensor technology or option, this option
provides an external access to the HART interface in
the transmitter. An intrinsically safe (IS) barrier inside the
transmitter allows the user to attach an external handheld field
communicator for programming and configuration. The external
interface is installed in the lower left cable/conduit port of the
transmitter and is intrinsically safe.
Figure 54. XNX Universal Transmitter with HART interface IS barrier installed
The HART protocol is a communication technology used
with smart process instrumentation, providing two-way
communication simultaneously with the 4-20mA analog signaling
used by traditional instrumentation equipment. For more detailed
information on HART, see the the
www.fieldcommgroup.org.
Implementation of the HART protocol in the transmitter:
• Meets HART 6.0 physical layer specification
• The physical layer is tested according to HART Physical
Layer Test Procedure, HCF_TEST-2.
• Data transfer rate: 1200 bps.
Installation and Operation
HART Protocol section and
HART devices can operate in point-to-point or multidrop
configurations.
CAUTION
!
Caution: Device address changes must be performed only by qualified service
personnel

Point-to-Point Mode

In point-to-point mode, the 4–20 mA signal is used to
communicate one process variable, while additional process
variables, configuration parameters, and other device data are
transferred via HART protocol, as shown in the illustration below.
The 4–20 mA analog signal is not affected by the HART signal.
Multiplexer
Barrier
Note: Instrument power is provided by an interface
Field Device
Figure 55. Point-to-point mode of operation
56
Control System
or Other Host Application
or external power source that is not shown.
Handheld Terminal