Basic PLC Ladder Programming Example 15

Table of Contents

Basic PLC Ladder Programming Training Example 15 :

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 Program for Automatic Door open Close

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.