LAARS MagnaTherm MGV - Installation, Operation and Maintenance Instructions - Manual (Page 61)

MagnaTherm Boilers and Water Heaters Page 57
Menu 21. Enabling COM2 Menu
9.9 Connections to a
Building Automation System
MagnaTherm boilers can be controlled and monitored
through the included Modbus ports. The Modbus
wiring must be completed according to the diagrams
shown below. If alternate communication protocols are
desired, LAARS offers “gateways” to allow BACnet,
LON, and other communications protocols. For
additional information on setting up Modbus and other
communication protocols, contact the factory.
Signals from the Building Automation System will be
connected to the COM2 terminals located on TBI-33A
through 35A of this master boiler display.
WARNING
When servicing the controls, label all wires
prior to disconnection. Wiring errors can cause
improper and dangerous operation. Verify
proper operation after servicing.
Figure 28. BAS Connections to a Lead/ Lag System
Lead or
master
boiler
Controller Controller
Master
System
display
TB3 - 24VAC
TB4 - NEU
Operator
interface
(HMI)
Customer
communication
(RS-485)
MB1 MB1 MB2 MB2
Second or
slave
boiler
Com1
Com2
Figure 29. BAS Connections to
a Single Boiler
Operator
interface
(HMI)
Boiler
Controller
MB1 MB2
Customer
communication
(RS-485)