AERCO BMS II BOILER - Manual (Page 28)

INSTALLATION
2-16
BMS II
RS
232
PORT
485 B (+)
485 A (-)
SHLD
(TERM. 3)
-
+ RS485
COMM
P/O I/O BOX
C-MORE
SLAVE
NETWORK BOILER 1
-
+ RS485
COMM
P/O I/O BOX
C-MORE
SLAVE
NETWORK BOILER 2
TO OTHER
NETWORK
BOILERS
(3 – 32)
RS
485
PORT
NOTE
THE LAST C-MORE SLAVE ON THE RS485 LOOP
MUST HAVE ITS TERMINATION RESISTOR (TERM)
AND BIAS (BIAS1, BIAS2) DIP SWITCHES TURNED
ON. REFER TO GF-114 MODBUS COMMUNICATION
MANUAL FOR DETAILS.
THE BIAS SWITCHES IN THE BMS II SHOULD BOTH
BE “OFF”
SET BOTH
SWITCHES
TO “OFF”
BIAS
SWITCHES
Figure 2-10. Sample RS485 (Modbus) Network For Benchmark or KC1000 Boilers
BMS II
RS
232
PORT
485 B (+)
485 A (-)
SHLD
(TERM. 3)
TO OTHER
NETWORK
BOILERS
(3 – 9)
RS
485
PORT
NOTE
THE LAST BCM SLAVE ON THE RS485 LOOP MUST
HAVE ITS TERMINATION RESISTOR (T) ACTIVATED.
REFER TO GF-115-C FOR MORE INFORMATION.
THE BIAS SWITCHES IN THE BMS II SHOULD BOTH
BE TURNED “ON”.
SET BOTH
SWITCHES
TO “ON”
BIAS
SWITCHES
B (+)
P/O BCM (Y2)
NETWORK BOILER 1
1
2
A (-)
MODBUS
B (+)
P/O BCM (Y2)
NETWORK BOILER 2
1
2
A (-)
MODBUS
Figure 2-11. Sample RS485 (Modbus) Network For Modulex Series Boilers