Automatic Door Open and Close system using PLC

In recent times, automation has taken boom all over the world and it looks impossible to live without automated things. We can see automated things in our daily life. Automatic door open and close is also one of the automated things in the world. We can see automatic door opening and closing systems in corporate offices, malls, elevators, etc.

Table of Contents

Automatic Door Open and Close system

The main working principle of automatic door open and close is to sense an object next to the door with the help of sensors and give this input to the PLC for the opening and closing operation of the door.

The biggest advantage of an automatic door open and close system is that there is no requirement of any supervision for its operation.

Automatic door open and close system

List of Input Outputs

Address Description Type
I0.0 Start Switch Input
I0.1 Stop Switch Input
I0.2 Object Detecting Sensor (S) Input
I0.3 Limit Switch 2 (LS2) Input
I0.4 Limit Switch 1 (LS1) Input
DB1 Timer Input
M0.0 Memory Memory
M0.1 Timer memory Memory
Q0.0 Door Open Output
Q0.1 Door Close Output

PLC Program and Explanation

The complete program is divided into two networks, network 1 and network 2. Don’t be afraid, you can divide a program into as many networks as you want.

Network 1 is used to Start and Stop the system, and Network 2 is used for the door open and close ladder program.

Automatic door open and close system ladder logic

The system is started and stopped using the switches.

If you want to start and stop the system using a single push button only, then you can refer to the following article, Single Push Button Start/Stop Ladder Logic Diagram


When the object detection sensor senses an object or people, it will open the door by a mechanism until Limit Switch 2 (LS2) is turned ON.

When there is no object in front of the object detection sensor and the door is open, the door will be closed with the help of a mechanism.

Before closing the door timer of 10 seconds is counted.

While closing the door, if the object detecting sensor senses an object, the closing of the door will immediately stop and the door will open again.

Automatic door open and close system ladder logic diagram

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