Honeywell XNX-AM Series, Technical Manual

Page: 18 / 207

XNX Universal Transmitter
Introduction 16
Options
Local HART
Available with any sensor technology or personality, an external
access to the HART interface in the transmitter is provided.
An intrinsically safe ( IS) barrier inside the transmitter gives
the user full control using a 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. For more information, see the HART
Protocol section.
Figure 6. XNX Universal Transmitter with HART interface IS barrier
Note: POD options are either relay, Modbus, or FOUNDATION Fieldbus.
NOTE
!
Relays
The relay option (XNX-Relay) provides 3 form “C” (SPDT)
normally open/normally closed (NO/NC) contacts for alarm and
fault indication. A remote reset
input (TB4) is provided to silence
alarms. Momentarily closing the the circuit between the pins of
TB4 performs the same function as the Reset Alarms & Faults
command.
The
remote reset switch (designated TB-4 and labeled “Remote
Reset SW”) is located on the relay option board. It provides
a remote hardware-based reset of faults and alarms to the
transmitter. In the event that direct access to the local and
HART
®
interfaces is not possible, alarms and faults from an XNX
transmitter may be reset remotely using a momentary switch.
This will momentarily close the circuit between the two pins of
TB4, providing the same functionality as a Reset Alarms & Faults
command performed from the main screen of thelocal user or the
HART interfaces.
Relays are not available when the Modbus
®
or FOUNDATION
Fieldbus options are installed.
The transmitter has three relays: relay 1 is for alarm level 1, relay 2
is for alarm level 2, and relay 3 is for faults and special states. Two
alarm levels can be set, allowing, for example, a level 1 alarm for
the immediate area when a certain gas concentration is detected
and a plant-wide level 2 alarm when a greater gas concentration is
detected.
The maximum
refresh rate of the relays is 2 seconds. See the Set
Alarm Values section for more information.