Semi-Automated Control of Tollgate Gate using PLC & DC Motor

Hi friends..

This project includes all circuits, programs and methods needed to design “Semi Automatic Gate Control Using PLC & DC Motor.

Basically before the vehicle passes Tollgate, Driver has to pay the taxes or there may be a need for security check. For many reasons, opening the gate manually is not efficient. With the emergence of improved technology, there are many brands of controller that are available in market today to control the gates. This is one of the simplest methods to design the electrical controlled gates using PLC & DC Motor.

Circuit Connection: Normally in tollgates, Servomotors are used to rotate the gate but here I have made the Gate rotation using DC Motor. DC motor will run with the help of DC supply aided by a battery or by AC to DC converter. Control is done by PLC. Forward and reverse rotation both program is required to open and close the gate. Two push buttons are used as inputs for the action of Open & Close which is connected to PLC. Micro switch is used to detect the final position of Gate while closing. Here Micro switch, OPEN and CLOSE switch are Normally OPEN (NO) connection. Variable resistor is used to fix the speed of the Motor.

Circuit Diagram:

Ladder Diagram:

According circuit diagram address of the input/output components are

1. Qo is FRW1

2. Q1 is FRW 2

3. Q2 is REV 1

4. Q3 is REV 2

5. I0 is OPEN SWITCH

6. I1 is CLOSE SWITCH and

7. I2 is Micro switch

Structure Diagram:

Working : Normally the Gate is closed. When OPEN switch is pressed, motor starts to rotate in anticlockwise direction. When Support arm touches the micro switch, PLC gets the signal to STOP the motor and thus the motor stops. PLC is now ready to close the Gate and it will wait for the CLOSE signal. Once the CLOSE button is pressed, the motor will start to run to clockwise direction for the programmed time (i.e. 50ms), after which the gate will close with help of gravity or weight of gate only.

While opening the Gate, CLOSE button will not work until the gate opens completely or until the micro switch is activated. It will prevent any occurrence of malfunction in the system. Gate cannot be closed suddenly. However, if the CLOSE button is activated by mistake, gate can be opened any time by activating the OPEN SWITCH.

For simulation purpose, we can use Siemen’s LOGO SOFT (click here to download) and the ladder diagram generated using this software is shown below.

For closing purpose, Timer Ton is used and the value of timer delay depends on the weight of the gate & speed of the motor. When the CLOSE SWITCH is pressed, timer starts to count and motor will run with help of supply. If timer reaches to the Preset value, motor will stop.

Note, Caution, If higher value of timer is set, motor may over run and the gate will be get damaged permanently. Please try to test Timer from lower value of time.

Over speed of motor may damage the gate and micro switch while opening the gate. Please try keeping higher value of resistance in variable resistor.

Please comment your queries if any.

Thank you all...

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About Praveen S

Hello everyone, I am Praveen S, currently employed as "Technical Design Engineer" for Polycab Wires Pvt Ltd , I am a BE Graduate in EEE from NMAMIT Nitte (Karnataka, India). I am very passionate about learning and sharing my knowledge relating to the areas of "Electrical and Electronics". Here's my blog to share my ideas and to improve myself.