(draft article)

We have a nice thermal management system already at home. It was produced by Wavin. 

It controls every room separately, opening/closing all of the heating pipe valves (and can control the cooling in the summer too, which is really nice thing, believe me). 

Has a nice internet control option too if you have the WTC netbox module at home, (You may give a try with the demo user: http://www.mywavinhome.com/, user/password is wavintest / wavintest) 

With or without the netbox module, the whole system communicates (and thus can be controlled) using ModBus commands. Modbus is a serial protocol which is widely used by building/industrial management, etc.

It has a TCP variant implementation too - and luckily, the WTC-NET1 module supports that mode. So I don't have to cable from arduino to WTCNET1 directly, just enough to setup a tcp/ip client connection to the module and send/receive the WTC1 commands.

Some possible commands from the WTC1NET service manual:

(Here is the whole service manual/full command list is interested)

Well, it sounds simple if you read this all together, getting the fact that it has errors (lot of analysis was required...). 

And the next thing that it is hard to find an arduino library for ModBus TCP.

I found one implementation here: http://myarduinoprojects.com/modbus.html but actually it was not working:

So, the first step was to fix the library....(I emailed the fixed version to the author to update on his webpage)

....then to get a good ModBus tester sofware to play and experience with the interface.

...then to intergrate this to Arduino:

(Article will be continued. And sorry for the typos, I am quit tired, that is the first draft of this entry. And this is just a hobby :) )