luamodbus documentation

[AngelesTR]

The device is not a standard modbus system, so I have to install a gateway to convert the data to standard RS485 modbus. I have to send a special command and the device responds with data. I don't really understand what I have to send to the device and what I have to read out....... I want to use an adfweb converter.
What is this function log(table.concat(buffer))? what data is buffer?
I can use this "mb:writereadregisters(write_reg_start, write_reg_value_1, write_reg_value_2, write_reg_value_3..., read_reg_start, read_reg_count)" to send the correct command but how do I get the response?

Thanks