DTU V00.02.22 turns off modbus

[VincentSC]

• Hoymiles MQTT version: 0.6.0
• Python version: Docker
• Operating System: RasPi5 + raspian

Description

Since 1 May I get the same problem as in #9 again. The DTU is at V00.02.22, and I suspect it was automatically updated on that day.

Modbus Error: [Input/Output] Modbus Error: [Invalid Message] No response received, expected at least 8 bytes (0 received)

According to https://www.photovoltaikforum.com/thread/221261-neues-firmware-update-2-22-f%C3%BCr-dtu-pro-erh%C3%A4ltlich/ this is a known problem

On https://github.com/ArekKubacki/Hoymiles-Plant-DTU-Pro I see:

!!! For 22 Version, if you choose "Export control", it prohibits MODBUS TCP. But "Remote control" still supports it. So you have to go to "Toolkit" in APP and then choose "Remote Control" from RS-485 Port Config under DTU Information. !!!

[VincentSC]

And to answer my own question. :)

On the German forum there was the answer. You need to put the DTU in "remote control mode", as it will close the modbus when in the "receiver mode". Not sure of these are the correct translations

In the installer app, go to "toolkit".

Then select the DTU. There you can change the mode.

The port does not matter, as 502 is still being used for modbus. One of the forum folks chose port 101, and mentioned that it does not need to be used by other modbus-devices.