AERCO Control System (ACS)
CHAPTER 2
: ACS Installation
11/22/2017
AERCO International, Inc.
•
100 Oritani Dr.
•
Blauvelt, New York 10913
Page 29 of 139
OMM-0081_0F
Phone: 800-526-0288
GF-131
2.7.2 RS485 Wiring for Modulex Series Boilers
RS485 wiring connections are made at the MODBUS terminals of each Boiler’s BCM Module as
shown in Figure 2-9. Connect the wiring as shown below:
RS485 Wiring at Boiler BCM of Modulex Boiler(s)
1.
Connect the positive lead to terminal
1
(MODBUS B +) of connector Y2.
2.
Connect the negative lead to terminal
2
(MODBUS A -) of connector Y2.
3.
DO NOT terminate the shields at the Boiler end of the RS485 loop. Connect the shields of
the incoming and outgoing leads together. The RS485 loop shield should only be
terminated at the ACS.
4.
The last BCM in the daisy-chain must have the termination jumper engaged as shown in
Figure 2-9
.
5.
The two ACS bias switches (
Figure 2-6
) must be activated by placing them in the down
position.
Y2
Y3
Y4
Y1
SW1
A1
I
0
BCM FRONT VIEW
7 6 5 4 3 2 1
Y2
JP2
JP1
T
C
V
JUMPER
SHOWN IN
“TERMINATED”
(UP) POSITION
MODBUS B
(+)
MODBUS A
(-
)
Figure 2-9: RS485 (Modbus) Wiring For Modulex Series Boilers
