I find it great, that you have taken things in your Hand, and at that point I also want to say "thank you" to Dario, Jiri and all other developers.
My activity with HR20-E and "openHR20 V1.0" started a few years ago, with the installation of the first HR20, wired by RS232-connection to a Windows-PC, and an early version of "openHR20 Suite". After solving some problems, this has been a comfortable combination.
I think, that this would be the lowest level for any "newcomer", and only success and progress would give the motivation to continue.
But now I found, that there is a difference between the Parameter-description in "openHR20 Suite V0.2.4.23954" and the actual usage in the flashed "OpenHR20_1.0.zip Last Update: 2014-07-06".
So, if an "e3" or "E:8" Error occurs after installation on a radiator, and he tries to do a correction at the wrong parameters, there will never be a success.
The second level has been to increase the amount to 5 "active" HR20-E, installed on radiators, and to hardwire them all via RS232 to a central located "COM-to-ETHERNET"-Adapter. Now they all could be controlled and configured on a Windows-PC via virtual-COM by "openHR20 Suite", or by "RealTerm" which also offers an alternative connection by their specific IP-Address and Port.
The third step for me has been to install a RaspberryPi3, which normally runs with 4W powerconsumtion without any interruption. It is setup with "fhem", and all HR20-E are connected as "ECMDDevice" via my local ETHERNET.
And this was the step from "single-heating-components" to an integrated "heating-system"
Accesspoints to be found here:
http://fhem.de/
http://fhem.de/fhem_DE.html
Up to now "fhem" is able to watch them, present actual Parameters and charts for each day, and save logfiles.
Also within "fhem" it is possible, to send Control Commands, such as "V" or "D", but no way was found to use Control Commands with more than one Byte, such as "A20" or "B1324".
And this was the reason, to check Google for additional Information, and so I came to GoogleGroups and your "openhr20-development".
I am not a specialist for C-programming, and used the Firmware just as it is.
Now I created an account at github, and found this repository:
https://github.com/OpenHR20/
As far as I can see, my " openHR20 V1.0" from 2014 is old stuff, but with some exeptions it is a running system.
I am more familiar to the external components and connections, and could share my experience.
And in addition to the 5 "active HR20-E" there is one more "inactive" on the workbench, which I used for my testing. It is also connected via RS232 and "COM-to-ETHERNET"-Adapter to "openHR20 Suite", or "RealTerm", or a Test version of "fhem", installed on a Windows10-PC.
And this setup is remaining to do any Tests.
As far as I can see, no connection has been established between "fhem" and "HR20", but both could get profit from this combination within the upcoming "IoT"
How do you think about that?
MFG Manfred