2�3�2 Relays - Honeywell XNX Technical Manual

XNX Universal Transmitter
2.3.2 Relays
The relay option (XNX-Relay) provides 3 form "C" SPCO contacts
for alarm and fault indication� TB4 allows alarms to be reset
remotely�
Note: This option is not available when the Modbus or Foundation
Fieldbus options are installed.
Wiring for the relays is through an available cable/conduit port to
a pluggable terminal block� See Figure 35 for the terminal block
legend�
Note: A second, black-handled screwdriver is included for use on
terminal blocks 2 and 4. This tool is smaller than the magnetic wand
and is designed to fit into the terminal connections on TB4.
The XNX 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� All special states are indicated by the fault relay�
Honeywell Analytics recommends that the fault relay be used in all
installations to maintain safe operation� See Set Alarm Values for
more information�
The relay state is refreshed every 2 seconds� The fault relay is
normally energized indicating proper operation� In the event of
power failure or fault, the C-NO connection will open�
Section 2 - Installation and Operation
TB4
Remote
Reset SW
Relay Ratings
250VAC 5A
24VDC 5A
3-1 NC
3-2 C
3-3 NO
3-4 NC
3-5 C
3-6 NO
3-7 NC
3-8 C
3-9 NO
TB-3 RELAY
Warning: Power
externally supplied.
Disconnect at source
prior to servicing.
Figure 59. XNX Relay Option Board Terminal Blocks
2.3.3 Modbus
The optional Modbus interface allows all transmitter local
user interface (LUI) functions and parameter settings to be
transmitted�
Modbus is a master-slaves protocol� Only one master (at a
time) is connected to the bus� Up to 247 slave nodes are also
connected to the same serial bus� Modbus communication is
always initiated by the master� The slave nodes never transmit
data without receiving a request from the master node� The slave
nodes never communicate with each other� The master node
initiates only one Modbus transaction at a time�
53
1
2
3
TB3
4
5
6
7
8
9
TB4
1
TB3 Relay Connections
Warning: Power externally
supplied, disconnect at source 2
prior to servicing
Relay Contact Ratings:
250 VAC 5 amps
24 VDC 5 amps
Relay
TB3
NC
C
NO
NC
C
NO
NC
C
NO
TB4
1
2