Has anybody experience with MODBUS to read temp sensors?

[Rudy M]

Hi Petr, 
Thanks again for sharing your knowledge. 
In the meantime, I've replaced the Raspberry Pi with a miniPC running Linux Mint 22 (Wilma) and an XFCE desktop. 

The miniPCs are identical (the one replacing the Raspberry Pi only has 8GB of RAM). 
All hardware and software are now the samel. 
What works on this PC works on the other... 

I tested your new listing, and... it runs 100% perfectly from the first start! 
Stopping and restarting multiple times is no longer a problem. 

In the beer installation, I've already replaced the DS18B20 with PT100 sensors (but I still need to connect them). 
One more question: 
As you may have noticed, I stored the sensor temperatures in an array labeled Temp!(x%). 

Should I have your listing read the sensors continuously? 
Or ON TIMER (e.g., 0.5 seconds) gosub...? 

(I would then create a small subroutine to print the three temperatures somewhere on the screen. 
(pe.:


brewkettle = xxx.x °C, water heater = xxx.x °C, cooling water valve = xxx.x °C) 

Regards,
Rudy M