PLC Ladder Logic for Three Motors drive Simultaneously with Interlocking using Siemens TIA Portal

In an industry a sequence of operation takes place with few motors. The sequence will take place one by one with certain time delay. In this article we will discuss about creating an appropriate PLC program for a sequence of three motor connected with interlock. 

Three Motors say M1, M2 & M3 are connected in a sequence. Once the start button pressed, the M1 start running and stay for 5 secs then M2 start and stay for 5 sec then M3 Start and stay for 5 sec. This sequence repeat until any interrupt takes place during the working When any one motor is pressed, for example M2 is pressed only M2 run and other motor stop. This happens for all motor. We will see how to implement this logic in PLC using Siemens Ladder Diagram programming language.

The circuit Schematic of Three Motors drive Simultaneously with Interlocking is shown below

PLC Ladder Logic for Three Motors drive 1
PLC Ladder Logic for Three Motors drive 3

Declaration of Input and Output for each PLC block

S. NoOperationInput/Output/OthersAddress of Each Block
1Start ButtonInput%M0.1
2Start Latch Coil (For continue “ON”)Latch(Associated Coil, Not Operative)%M0.1
3Dummy Coil_01(To Start the Timer)Output%Q0.0
4Dummy Latch Coil_02(For continue “ON”)Latch(Associated Coil, Not Operative)%Q0.0
5Motor Coil 1Output%Q0.1
6Motor Coil 2Output%Q0.2
7Motor Coil 3Output%Q0.3
8Motor 1 Start button(Interrupt Switch) Input(Separate Switch for Motor 1)%M0.2
9Motor 2 Start button(Interrupt Switch)Input(Separate Switch for Motor 2)%M0.3
10Motor 3 Start button(Interrupt Switch)Input(Separate Switch for Motor 3)%M0.4
11Timer_1Timer 1DB2
12Timer_1.QTimer 1 relayNot Specific
13Timer_2Timer 2DB2
14Timer_2.QTimer 2 relayNot Specific
15Timer_3Timer 3DB2
16Timer_3.QTimer 3 relayNot Specific
17Stop(Common for entire operation)Input%M0.0

Various Phases of working of Ladder Logic

The PLC Program is written in Siemen’s software using TIA Portal V16. As per the above statement, the PLC program as  have Six sections

  1. Start and Stop operation for Three Motor 
  • In this section of ladder logic, we have start and stop button.Once Start pushbutton pressed “Dummy_coil_00” gets energized. The dummy coil is introduced to start the first Motor M1.
  • The Start logic is build using latching concept (Push button).
  • The stop button can be used to stop the entire process.
PLC Ladder Logic for Three Motors drive 3
  1. Motor 1 Working: 
  • Once the “Dummy_coil_00” energized the Motor 1 start(timer is set for 5 sec) and stay for 5 Second through “Timer_1.Q”The Motor 2 and Motor 3 Coil is closed. Since both the motor are in “OFF” Condition. The Motor 1 Start coil used for Switch “ON” the Motor 1 Separately. 
  • The Timer _1(DB2) is switched on through same coil the “Dummy_coil_00”. (The Timer_1 use to enable “Timer_1.Q” coil for 5 sec)
PLC Ladder Logic for Three Motors drive 4
  1. Motor 2 Working:
  • The Motor 2 start(timer is set for 5 sec) and stay for 5 Second through “Timer_2.Q” The Motor 1 coil closed. Since Motor 1 in “OFF” Condition. The Motor 2 Start coil used for Switch “ON” the Motor 2 Separately
PLC Ladder Logic for Three Motors drive 5
  1. Motor 3 Working:

The Motor 3 start(timer is set for 5 sec) and stay for 5 Second through “Timer_3.Q” The Motor 2 coil closed. Since Motor 2 in “OFF” Condition. The Motor 3 Start coil used for Switch “ON” the Motor 3 Separately

PLC Ladder Logic for Three Motors drive 6
  1. Timer 2 for Motor 2:

We will see working of Timer 2 and Timer 3 in this phase. The Timer 2 is constructed in such way that the Motor 2 “ON” for 5 sec. Therefore, the Motor 2 Coil is Open until Motor 2 “ON”. During Motor 2 is “ON” the Motor 3 is “OFF” the associated coil Motor 3 is Closed.

PLC Ladder Logic for Three Motors drive 7
  1. Timer 3 for Motor:

The Timer 3 is constructed in such way that the Motor 3 “ON” for 5 sec. Therefore, the Motor 3 Coil is Open until Motor 3 “ON”. During Motor 3 is “ON” the Motor 1 is “OFF” the associated coil Motor 1 is Closed.

PLC Ladder Logic for Three Motors drive 8

How to program ladder logic using SIEMENS TIA portal (Simulation) information is available in below mentioned link

How to use Siemens TIA Portal to create PLC Ladder Logic for three phase motor Forward and Reverse

Simulation screenshots of each phase

  1. Initial stage of ladder Simulation started by pressing the “Start” button(%M.0) . The  Motor 1 run for 5 sec with help of timer 1. Motor 1 Start or Motor 2 Start or Motor 3 Start button, need not be pressed(Until Interrupt is required)
PLC Ladder Logic for Three Motors drive  9

  1. Motor 2 run automatically after 5 sec and run for 5 sec using Timer 2(timer is set for 5 sec). Motor 1 will stop by Timer 1. Motor 1 Start or Motor 2 Start or Motor 3 Start button, need not be pressed(Until Interrupt is required)
PLC Ladder Logic for Three Motors drive 10

  1. Motor 3 run automatically after 5 sec and run for 5 sec using Timer 3(timer is set for 5 sec). Motor 2 will stop by Timer 2.Motor 1 Start or Motor 2 Start or Motor 3 Start button, need not be pressed(Until Interrupt is required)
PLC Ladder Logic for Three Motors drive 11
  1. The Timer 2 and Timer 3 operation between Motor 2 and Motor 3. Continuous operation of Motor M1, Motor M2 and Motor 3 in sequence without stop. (Until Interrupt is required)
PLC Ladder Logic for Three Motors drive 12

  1. Suddenly if any one Motor switch is pressed. The corresponding Motor alone run and other Motor stopped.(For example: “Motor 2 Start” button is pressed Motor 2 alone run and other Motor Stopped)(Interrupt Enabled)
PLC Ladder Logic for Three Motors drive 13

We successfully developed PLC ladder logic with the above exercise, and we also tested the ladder logic using simulation.

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