Honeywell Centra Line CLEA2000B21 - BACnet MS;TP Bus Setup; BACnet MS;TP Connection Considerations; RS485-1 BACnet MS;TP Connection

EAGLE CONTROLLER – INSTALLATION & COMMISSIONING INSTRUCTIONS
23 EN1Z-0970GE51 R1112
BACNET MS/TP BUS CONNECTION
The EAGLE Controller features two RS485 interfaces to which BACnet MS/TP devices can be connected: RS485-1 (consisting
of push-in terminals 24 [GND-1], 25, and 26) and/or RS485-2 (consisting of push-in terminals 29, 30, and 31 [GND-2]).
NOTE: GND-2 is internally connected with 24V-0 (terminal 1) and system GND (terminals 19+37)
Considerations
 RS485-1 (isolated)
˗ Max. BACnet MS/TP bus length: 800-1200 meters, depending on baud rate (see section “RS485 Standard” on pg. 8)
˗ Must conform to EIA-RS485 cabling guidelines
 RS485-2 (non-isolated)
˗ Max. BACnet MS/TP bus length: 1200 meters
˗ Use only shielded, twisted-pair cable
˗ Ground noise should not exceed the EIA-485 common mode voltage limit
˗ Must conform to EIA-RS485 cabling guidelines
 Max. no. of BACnet MS/TP devices per RS485 interface: 32
 Max. no of BACnet MS/TP devices per EAGLE: 64
Connecting RS485-1 to BACnet MS/TP Buses
1 2
24V~ 24~0
EAGLE
MID
END BI
A
S
MID
24
2526
R T
BACnet
Module #1
RS485 +
RS485 -
GND
BACnet
Module #N
**
*Connect, if available.
120 Ohm
RS485 +
RS485 -
GND
F1
230 V
24 V
L
GND-1GND-1
+5V
ISO
RS485-1 (+) RS485-1 (-)
47 kOHM
47 kOHM
Fig. 33. Connection of RS485-1 to a BACnet MS/TP Bus
NOTE: Always power the EAGLE and connected BACnet MS/TP modules with separate transformers.
NOTE: N = max. 30 modules.
NOTE: For “L,” see section “RS485 Standard” on pg. 8.
NOTE: If any devices are not electrically isolated, signal ground connection is recommended. See section “RS485 Standard”
on pg. 8).
Termination resistors must be inserted directly into the terminals of the individual BACnet MS/TP modules. In the above figure,
the EAGLE is shown operating as the Master BACnet controller; its slide switch is hence set to “MID.”