Honeywell ComfortPoint Open CPO-PC400-W Manual page 25

Connection to Field Bus Modules Powered by a Separate Transformer
This configuration has the advantage of allowing the FBAs to be distributed through a building.
CONNECTION VIA RS485 INTERFACES 1, 2, OR 3
R
T
5V_ISO
GND_ISO
Isola on
Barrier
5V
GND RX TX
CPO-PC400-W/CPO-PC400-UW
Fig. 16. Connection (L > 3 m) of RS485 interfaces 1, 2, or 3 (RS485 interface 1 shown) to a Field Bus
NOTES:
— Signal ground (signal reference) connection is recommended. For more information, see "General Information
on the RS485 Standard" section on page 7.
— For communication cable lengths, transmission speeds, and termination, see "General Information on the
RS485 Standard" section on page 7.
110VAC/230VAC
24VAC
F1
25
CPO-PC400-W/CPO-PC400-UW HVAC CONTROLLER
L > 3m
FBA #1
Shielding
Op onal
A
F2
24VAC
110VAC/230VAC
FBA #N
R
T
A
F3
24VAC
C
110VAC/230VAC
A+C = MAX.20 Meters
EN0B-0085 IE10 R0420
C