Tft Series Installation and Operation Instructions
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Trinity
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Modbus Communication Connections
The Trinity Tft uses Modbus for communicating data to and from the boiler controller. Effectively the boiler
incorporates three (3) Modbus communication ports:
1.
Controller MB1 to Display COM1
– provides communication of all data between the boiler controller and
the user interface (touch-screen display). Controller communication port “MB1” is factory wired to
communication port “COM1” of the touch-screen display.
2.
Controller MB2 to Field Terminals (see Table 12-2a; Locations 1-3)
– allows for communication
between boilers for the purpose of staging/cascading; as many as 8 boilers can be “daisy-chained” together.
For lone boiler applications, this port can be alternatively used for communication to an external device (i.e.
Building Automation System, BAS). Controller communication port “MB2” is factory wired to Low
Voltage field connections DATA (+), DATA (-), and DATA COM (see Figure 12-2).
3.
Display COM2
– the new Tft touch-screen display provides a spare Modbus communication port; the extra
port allows for dedicated communication to an external device (i.e. Building Automation System, BAS).
Display communication port “COM2” is accessed from the rear of the touch-screen display, see Figure 12-3
for wiring instructions. See Figure 16-3 for instructions on accessing the rear of the touch-screen display.
Figure 12-3 COM2 Modbus Wiring (Rear of Display)
