I am now working on PHP part. I know pretty less about IOT so the question might be strange, but I will be appreciate if anyone can give me an example, concept or even a way to learn.
The idea way is to let the PLC device can keep connection with server through wifi and modbus tcp to send and read data. the PLC is the modbus client(master) and PHP is the modbus slave(server). the PLC and PHP are placed in different IP address, which means the connection has to be available in not only LAN but WAN. Thank you for any suggestion.