How to check if OTGW is actually connected to the boiler?

This Forum is about the Opentherm gateway (OTGW) from Schelte

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AndrewFG
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How to check if OTGW is actually connected to the boiler?

Post by AndrewFG »

Sorry if this may be a dumb question, but is there some command whereby one can query if the OTGW is actually connected to the boiler (resp. the thermostat)? Reason for asking is that my bus wire had become physically detached from the OTGW, and there seemed to be no way to raise an alarm about it. Or??
hvxl
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Re: How to check if OTGW is actually connected to the boiler?

Post by hvxl »

Whenever the thermostat is connected or disconnected, the OTGW reports that event. There currently is no command to check the state, although it would only take 2 instructions to add it to the PR=R command. You could use DP=61 and check bit 1. Bit that is very firmware version specific and may change.

The boiler interface is optically isolated and only produces a digital high/low signal. So it is not possible to check if there is any voltage coming from the boiler. A disconnected boiler simply results in a logical inactive level. The only thing that can possibly be used as an indication is whether responses for messages are received. The OTGW doesn't do that at the moment.
Schelte
AndrewFG
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Re: How to check if OTGW is actually connected to the boiler?

Post by AndrewFG »

Ah. Ok. Many thanks for the insights.
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