siemens_7KT-PAC1600 Interfacing modbus RTU with siemens 7KT PAC1600 you need minimalmodbus ad serial sudo apt install -y python3-pip python3 pip3 install minimalmodbus /dev/ttyUSB0 is the port name of your rs485 to usb converter usage : python3 7kt.py 1 to got all values python3 7kt.py 1 power.l1 to got instant power of L1