Hi Krzysztof, The DTSU666 meter allows reading data using both functions 03 and 04. I haven't noticed any problems with the readings with function 04. Do you have a standard DTSU666 software version - not customized for Huawei, Hoymiles etc.? Just in case, I put on Github a plugin version that reads ...

Hi.

Following the example of MFxMF I have written plugin for Chint DTSU666 smart meter:
https://github.com/elfabriceu/DTSU666-Modbus
log: Any feedback or suggestions are appreciated.

Best regards
Robert