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SETECNA
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14/09/2016
23/09/16 17.56
Gateway MODBUS-to-Opentherm MB-OTG
Technical manual
3.3
MODbus Register and OpenTherm protocol Mapping
The Gateway maps the exchanged informations (some information read, other written) with the Boiler in as
many Register or Coils of the MODbus protocol.
In particular, the Gateway recognize the following MODbus protocol commands:
•
0x01: Read Coil
•
0x03: Read Holding Register
•
0x05: Write Single Coil
•
0x06: Write Single Register
The gateway reads from the Boiler the information by using the OpenTherm protocol and memorize those
data in Holding Registers or Coils (depending if the read value is scalar or Boolean type), that are readable
by MODbus; the holding registers and the coils writable by using MODbus are transmitted in their turn to
the Boiler.
