AERCO Modbus Communications Manual - Manual (Page 70)

GF-114
MODBUS
Communication
Chapter 4
OMM-0035_0C USER MANUAL Hardware Setup & Installation
Page 70 of 200 AERCO International, Inc. • 100 Oritani Dr. • Blauvelt, NY 10913 • Ph.: 800-526-0288 05/18/12
4.4 MODBUS NETWORK WIRING DIAGRAMS
Sample Modbus Network wiring diagrams for the basic circuit configurations are provided in
paragraphs 4.4.1 through 4.4.3. It should be noted that these diagrams are only intended as a
guide and do not include all possible scenarios. If a third-party EMS is being utilized, refer to the
manufacturer’s manual prior to attempting any network wiring connections.
CAUTION
It is imperative that polarity be maintained between all Modbus
Network connections. The Network will not operate if the proper
polarity is not maintained. Also, twisted-pair wiring shield should
only be terminated at the controlling Master Controller for the
Modbus Network.
4.4.1 Wiring Diagrams for Master EMS Controlling BMS Slaves With Legacy
(PWM) Boilers
Figure 4-11 provides a sample wiring diagram for a BMS (Model 168) being controlled by an
EMS Master equipped with a RS485 port.
4.4.2 Wiring Diagram for Master BMS/BMS II/ACS Controlling Networked C-More
Slaves
Wiring connections for the “Network” Boilers are made at the BMS/BMS II/ACS RS485 port as
shown in Figure 4-12. In addition, for a BMS (only) up to 8 “Legacy” Boilers can be wired to the
PWM terminal strip to allow control of up to 40 Boilers by one BMS. The BMS PWM terminal
connections can also be used to connect AERCO Boilers which utilize older types of control
systems, such as Modular Control Boxes, or C-More Controllers equipped with software version
1.61 or lower. Refer to BMS Manual GF-108M for additional setup details for the PWM “Legacy”
Boilers. BMS II and ACS units do not support PWM, therefore disregard the PWM terminal
connections shown in Figure 4-12. BMS II/ACS units can only operate networked boilers with C-
More control systems.
4.4.3 Wiring Diagram For EMS Master Controlling C-More Controller Slaves
Figure 4-13 provides a sample wiring diagram for an EMS equipped with a RS485 port. If the
EMS contains a 4-wire RS485 port, refer to Figure 4-11, Detail “A” for additional wiring details.