5 Ventilation Control
To couple the ventilation (Thermos200, Paul-Lüfutng) to my heating control has two motivations: On first hand I"d like to log and monitor the air temperatures, secondly it might be a good idea to synchronize the periods of maximal ventilation to times the oven is ignited and loading the storage tank.
1. Replace the control panel
Since the requested Temperatures are provided to the control panel and of course this is used to set the ventilation mode, I thought it should be the easy way to take over this communication - instead of mounting my own temperature sensors and figure out how to operate the blowers.
While I tried to understand the communication to the control panel, I figured out that the ventilation control and the panel need continuous communication to keep alive. Therefore I wrote a C program to listen to the ventilation and always reply the expected message. If you enable the debug it will depict the messages which are transmitted via the bus.
If this program is started as background task
The Thermos control panel consists only of 5 buttons to operate the system. For each button press one of the standard 133 messages has to exchanged by the button command.
To exchange these pieces of information between thermos200.c and HV_thermos200.php I use named pipes "FIFO". To get them working without blocking, operating with the necessary rights of program and pipes was a bit of trial and error, but if you follow my example you should be fine.
This way I am able to mimik the control panel, send one button press after the other and display the replied content.
2. Build you power supply and controlBy all the experience I got, I"d say, this is the much easier approach.