Honeywell Unitary User Manual

HONEYWELL UNITARY CONTROLLER - 230 VAC - INSTALLATION INSTRUCTIONS
31-00610-01 26
BACnet
TM
MS/TP Wiring Example
Fig. 22 Connection to a BACnet™ MS/TP Bus
NOTE:
• Suppose any of the devices are electrically isolated. It is recommended that those devices be connected to
the ground terminal (SHLD). See TIA/EIA 485 Cable Specifications.
• The 120 Ω termination resistor must be inserted directly into the terminals of both end devices.
• If shielding is used, the shielding of each individual bus segment should be separately connected at one end
to a verified earth ground.
• Always power each controller and the connected slaves via separate transformers.
• Between devices equipped with non-isolated RS-485 bus interfaces, potential differences of max. ±7 VDC are
allowed. Further, this bus should not extend beyond a single building.
• The SHLD (terminal 44) on the BACnet™
MS/TP controller is a free-floating terminal and is not connected to
any signal common.
BACnet
TM
MS/TP Wiring Setup Using Signal Common Example
Fig. 23 Connection to BACnet MS/TP Bus (signal common)
NOTE:
1) A single twisted pair has to be used for terminal 42 (+) and terminal 43 (-).
2) Terminal 47 can be used as COM for BACnet™ MS/TP wiring.
3) The plant controller is displayed on the above diagram for illustration purpose only. Kindly refer to the plant
controller documentation for more details about the wiring.
PLANT CONTROLLERS
RS485 Reference
RS485
-
RS485
+
BACnet MS/TP CONTROLLER
SHLD
+
-
BACnet MS/TP CONTROLLER
SHLD
+
-
BACnet MS/TP CONTROLLER
SHLD
+
-
120
Shield
Shield
PLANT CONTROLLERS
RS485 Reference
RS485
-
RS485
+
LEGACY CONTROLLER
GND
C1+
C1-
BACNET MS/TP UNITARY CONTROLLER
SHLD
+
-
LEGACY CONTROLLER
COM
+
-
GND
C1+
C1-
42 43 44 45 46 47
Signal Common
120
Shield
Shield
Signal Common
MS/TP 1 RS485 1

Honeywell Unitary Specifications

General

Brand	Honeywell
Model	Unitary
Category	Controller
Language	English