Honeywell CENTRA LINE EAGLEHAWK NX - Connecting EAGLEHAWK NX Via Its RS485-2 Interface to a Bacnet MS;TP Bus

EAGLEHAWK NX CONTROLLER – INSTALLATION & COMMISSIONING INSTRUCTIONS
EN1Z-1039GE51 R1218 42
Connecting EAGLEHAWK NX via its RS485-2 Interface to a BACnet MS/TP Bus
With regards to Fig. 47 and Fig. 48, please note the following:
NOTE: Always power each EAGLEHAWK NX controller and the connected BACnet MS/TP modules via separate transformers.
NOTE: For "L," see section "RS485 Standard" on pg. 10.
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. 10.
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 EAGLEHAWK NX 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
END BI
A
S
MID
NO EFFECT ON RS485-2
*CONNECT GND, IF AVAILABLE.
120 OHM
EAGLE-
HAWK NX
Fig. 47. Connection of a single EAGLEHAWK NX controller via its RS485-2 interface 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 EAGLEHAWK NX 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
END BI
A
S
MID
MID
END BI
A
S
MID
MID
*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
END BI
A
S
MID
NO EFFECT ON RS485-2
END BI
A
S
MID
NO EFFECT ON RS485-2
EAGLE-
HAWK NX
EAGLE-
HAWK NX
EAGLE-
HAWK NX
EAGLE-
HAWK NX
Fig. 48. Connection of multiple EAGLEHAWK NX controllers via their RS485-2 interfaces to a BACnet MS/TP Bus