Case study of a fire-tube steam boiler automated with an Industrial Shields PLC with relay outputs and WiFi. The PLC checks the water with a level sensor and fills the boiler with the pump, purges the combustion gases with the fan, lights the burner with the ignition transformer and the gas solenoid valve, and confirms the flame with a flame sensor. With no flame it repeats the ignition three times, and after a fourth failure it purges and aborts. With a flame, it keeps the pressure between 1 and 2 bar. A Panel PC on Ethernet shows the live values and the local alerts, and the data and the remote alerts go to a web server over WiFi.

The PDF covers the challenge, the three stages (prepare, ignite, hold), the system architecture with the signal list and the hardware used. Interactive version: steam boiler automation case study online.