How to Interlock Two Motors in PLC Using TIA Portal – Step-by-Step Guide

 

If you're new to PLC programming and want to learn something exciting, you're in the right place! Today, we’ll talk about how to interlock two motors in a PLC using TIA Portal, complete with a ladder diagram and HMI setup. This is a beginner-friendly tutorial, so let’s get started step by step. 🚀

1️⃣ Start Your Project

First, open TIA Portal and create a new project. Give it a name like "Motor Interlocking." Once done, add a new device, specifically an S7-1200 PLC. Don’t forget to set up the security configuration for safe operation.

2️⃣ Add HMI Screen

Next, add an HMI (Human-Machine Interface) screen to your project. Connect the HMI to the PLC by setting up the communication link.

3️⃣ Define Tags

Go to the Default Tag Table and create tags for the following:

• Start Motor 1
• Stop Motor 1
• Start Motor 2
• Stop Motor 2
• Motor 1 (output)
• Motor 2 (output)

Tags are like labels that help the PLC and HMI communicate.

4️⃣ Create the Ladder Diagram

Now, go to the OB1 file and start building your ladder diagram:

• Network 1: Add the Start button, Stop button, and Motor 1 output. Don’t forget to add a latch so the motor stays ON after the Start button is released.

• Network 2: Add similar logic for Motor 2 but with a twist—insert a Normally Closed (NC) switch linked to Motor 1. This creates the interlock, ensuring Motor 2 won’t start if Motor 1 is running.

5️⃣ Design the HMI Screen

Switch to the HMI screen to design a user-friendly interface:

• Add Start and Stop buttons for both motors. Assign the tags you created earlier.
• Customize the appearance of buttons by changing colors and adding events like SetBit on press and ResetBit on release.
• Add indicator circles for each motor and set animations to show ON/OFF status with different colors.

6️⃣ Simulate the Program

Finally, start the PLC simulation and connect the HMI server. Test the buttons and indicators to make sure everything works as expected. Try pressing Start and Stop on the HMI to see the interlocking logic in action!

Wrap-Up

And that’s it! You’ve successfully created a motor interlocking system in PLC using TIA Portal. This project is simple yet practical, helping you understand how to control multiple motors safely.

If you found this guide helpful, share it with others, and don’t forget to subscribe to Easy Electra for more electrical and automation tutorials. Let’s keep learning together! ⚡