Modbus TCP Client for Kostal Inverter

Using Arduino Networking, Protocols, and Devices
6

MaggoB:
Read Out Register 4
Arduino Code:
res = modbusRequest(SMA_UID, 40003, 1, regs);
Serial.print("Error :");Serial.println(res);
if (modbusError(res)) { return false;}
else { Serial.print("Register 4003 Content:");Serial.println(regs[0]);}

Kostal Doku
Addr (hex) Addr (dec) Description Unit Format N1) Access Function Code

0x04 4 MODBUS Unit-ID - U16 1 R/W 0x03

Result Serial Monitor
Error :0
Register 4003 Content:1 (shall be 71 !!)

read 0x04 or 0x03 not 40003, if you want the uid register

registers over 40000 are SunSpec register