OTG and modbus

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OTG and modbus

Postby c.man » Thu Apr 02, 2015 9:44 pm

I want link Opentherm Gateway in a network modbus.
Is it possible ?
If yes, How to do ?
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Re: OTG and modbus

Postby ModbusMan » Sun Dec 13, 2015 10:04 pm

You posted this some time ago so I don't know if you managed to solve your problem yet...

Good News is it is possible (as are most things) but you are gonna have to do some work to get there.
Quick question. Are you only interested in monitoring the data from OTGW or do you need to control the boiler as well?

You will need some device to communicate with the OTGW and translate everything into Modbus. You can get info from OTGW in 3 ways. 1: Mosquitto (MQTT), 2: Sending a request via the web interface or 3:DBus.
I have an OTGW with USB connection and I use a RPI (Raspberry Pi) running FHEM software to retrieve data from the OTGW using MQTT. Since FHEM also has a Modbus module it should be possible to convert this to Modbus TCP. (Assuming that you have a RPI with ethernet port.) Modbus RTU (serial port) is also in theory possible but probably requires extra hardware/programming effort.

Hope that this helps...

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