Sharing some expérience (again) - the regulation is not very satisfactory with my big/old cast iron radiators. If you ignore the glitch of the orange filling in the graph below (of which the variable edge <>21°C is the temperature fed back to the valve), we can see that there is a considerable delay in the adjustement of the valve opening.
That results in over- and underheating which requires me to cover/uncover myself…
You need to setup an automation for each radiator.and the script presented above would better be adapted to use “fields” that you can use as a parameter.
Personnaly, I use my automation blueprint which proposes fields(parameters), which is reused for every TRVI have.
Note that when you have two TRVs in the same room, you better also update the load balancing which implies that you ensure you get the load of both TRVs, average them and send that back to both TRVs.
There is at least one discussion on this forum,
And you can read more details in this documentation: