CentraLine EAGLE - Connecting RS485-2 to Bacnet MS;TP Buses

EAGLE CONTROLLER – INSTALLATION & COMMISSIONING INSTRUCTIONS
EN1Z-0970GE51 R0918 30
Connecting RS485-2 to BACnet MS/TP Buses
With regards to Fig. 45 and Fig. 46, please note the following:
NOTE: Always power each EAGLE and the connected BACnet MS/TP modules via separate transformers.
NOTE: For "L," see section "RS485 Standard" on pg. 9.
NOTE: If any of the devices are electrically isolated, it is recommended that those devices be connected to signal ground.
See section "RS485 Standard" on pg. 9.
NOTE: Between devices equipped with non-isolated RS485 bus interfaces, potential differences of max. ±7 V are allowed.
Further, this bus should not extend beyond a single building.
Example 1: Single EAGLE Controller and Connected BACnet Modules (with inserted termination resistor)
1 2
24V~ 24~0
2930 31
GND-2
GND-2+5V
RS485-2 (+) RS485-2 (-)
550 OHM 550 OHM130 OHM
F1
230 V
24 V
R T
BACnet
Module #2
RS485 +
RS485 -
GND
BACnet
Module #3
BACnet
Module #4
BACnet
Module #N-1
BACnet
Module #N
RS485 + RS485 + RS485 + RS485 +
RS485 - RS485 - RS485 - RS485 -
GND GND GND GND
L
BACnet
Module #1
EAGLE
*CONNECT GND, IF AVAILABLE.
RS485-2
120 Ohm
END BI
A
S
MID
NO EFFECT ON RS485-2
Fig. 45. Connection of RS485-2 to a BACnet MS/TP Bus
The termination resistor must be inserted directly into the terminals of the last BACnet MS/TP module.
Example 2: Multiple EAGLE Controllers and Connected BACnet Modules
1 12 2
24V~ 24V~ 24~0 24~0
29 2930 3031 31
GND-2 GND-2
GND-2 GND-2+5V +5V
RS485-2 (+) RS485-2 (+)RS485-2 (-) RS485-2 (-)
550 OHM 550 OHM550 OHM 550 OHM130 OHM 130 OHM
F1 F1
230 V 230 V
24 V 24 V
1 12 2
24V~ 24V~ 24~0 24~0
24 2425 2526 26
RS485 +
RS485 -
GND
BACnet
Module
RS485 +
RS485 -
GND
F1 F1
230 V 230 V
24 V 24 V
L
GND-1 GND-1
+5V
ISO +5V ISO
RS485-1 (+) RS485-1 (+)RS485-1 (-) RS485-1 (-)
47 kOHM 47 kOHM
*CONNECT GND, IF AVAILABLE.
GND-1
47 kOHM
GND-1
47 kOHM
BACnet
Module #1
BACnet
Module #2
BACnet
Module #3
BACnet
Module #N-1
BACnet
Module #N
EAGLE EAGLE EAGLE EAGLE
RS485-2 RS485-2RS485-1 RS485-1
END BI
A
S
MID
NO EFFECT ON RS485-2
END BI
A
S
MID
NO EFFECT ON RS485-2
MID
END BIAS MID
MID
END BIAS MID
Fig. 46. Connection of RS485-2 to a BACnet MS/TP Bus