Motor ON OFF Logic in PLC

Last updated: March 4, 2021 2:21 pm

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PLC Tutorials

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Develop ladder logic program for Motor ON OFF according to the logic given below,

The start button is pressed to start the conveyor motor
Cases move past the proximity switch and increment the counter’s accumulator value.
After the count of 3, the conveyor motor stops automatically and the counter’s accumulator value is reset to 0. Restart button is used to start the process from the beginning.
The conveyor motor can be stopped and started manually at any time without loss of the accumulator count.
Accumulated count of the counter can be reset manually at any time by means of the count reset button.

PLC Motor Logic

Motor Logic Explanation

Rung 0000:

Start/Stop PB latched with memory B3:0/0.

Contents

Rung 0001:

B3:0/0 enabled to turn ON conveyor motor (O:0/0 ). B3:0/1 is connected in series with normally closed contact to break the line when counter accumulator value reached 3.

Rung 0002:

B3:0/0 and proximity sensor (I:0/2) are connected in series to input the counter presented at 3 with one shot coil.

Rung 0003:

B3:0/0 and comparator block is used to enable B3:0/1 to turn OFF conveyor motor. It is also latched to avoid to restrict the motor to turn ON again. Restart button is pressed to start the process from the beginning.