# Basic PLC Ladder Programming Example 15

## Automatic Door Open Close System PLC Ladder Program Basic PLC Ladder Programming Training Examples for Beginners. Hi Friends here we are starting a series of Free Training on PLC Ladder Programming. These PLC Ladder Programs are important to get basics of Ladder Programs

### PLC Ladder Practice Problem:

• When someone enters the infrared sensing field, opening motor starts working to open the door automatically till the door touches the opening limit switch  If the door touches the opening limit switch for 7 sec and nobody
enters the sensing field, the closing motor starts working to close the door automatically till the closing limit switch touched together.
Stop the closing action immediately if someone enters the sensing field during the door closing process.
Topics Covered in this example is Automatic opening closing Door PLC Program .
Number of PLC Inputs Required

X0 – X0 = ON when someone enters the sensing field.
X1 – Closing limit switch. X1 = ON when 2 switches touched together.
X2 – Opening limit switch. X2 = ON when the door touched the switches.
Number of PLC Outputs Required

Y0 -Opening motor
Y1 – Closing motor
Number of PLC Timers Required

T0 – 7 sec timer. Time base: 100ms
Number of PLC internal memory flag Required

M1013 – 1s clock

### PLC Ladder Programming:

 PLC Ladder Program for Automatic Door open Close

### PLC Ladder Programming Description:

•  X0 = ON if someone enters the sensing field of the infrared sensor. Y0 will be ON and latched, and the door will be opened as long as the opening limit switches X2 = OFF.
• When the door touches the opening limit switches, X2 = ON. The timer T0 will start to count for 7 sec if no one enters the sensing field (X0 = OFF). After 7 sec., Y1 will be ON and latched and the door will be closed.
• During the closing process, X0 = ON if someone enters the sensing field. The NC contact X0 will be activated to turn Y1 off. Because X0 = ON, X2 = OFF and Y1 = OFF, Y0 will be ON and the door will be opened once again.