The steps to control the air compressor using Siemens S7-200 PLC (6ES712-1BB23-0XB0) are as follows:

hardware configuration

Connect the pressure sensor signal to the analog input of the PLC (EM231 module needs to be expanded), and connect the start stop button and overload signal to the digital input terminals (I0.0-I0.7); Connect the contactor coil and alarm indicator light to the output terminals (Q0.0-Q0.4).

programming

Write ladder diagram logic in STEP 7-Micro/WIN:

Read the pressure value and compare it with the set range. When it exceeds the limit, trigger Q0.0 (compressor start stop)

Monitoring overload signal (I0.5) triggers Q0.1 (fault alarm) and stops the machine

Set automatic/manual mode switch (I0.6)

Security debugging

Firstly, disconnect the load test logic action, confirm the pressure threshold and delay protection parameters (usually set to 0.5-1MPa start stop, 30 second delay to prevent frequent startup), and finally run with load and monitor the current stability.