I have a De Dietrich MCA65 gas boiler with a DIEMATIC iSystem controller, I use a Waveshare RS485 TO POE ETH converter (B).:
https://www.waveshare.com/wiki/RS485_TO_POE_ETH_(B)
and I get the same error messages, sometimes after two minutes and sometimes after three hours, completely irregularly.:
2024-10-14 15:58:48,919 - DDModbus - WARNING - No answer to masterReadAnalog
2024-10-14 15:58:48,919 - Diematic - WARNING - ModBus Master Slave Synchro Error
2024-10-14 15:58:56,036 - Diematic - INFO - ModBus Master Slave Synchro OK