Fixing a Communication Error on a PLC: A Step-by-Step Guide

Machine service & troubleshooting
Rick Zand|December 6, 2023

Occasionally, users come across a communication error message on their New Tech Programmable Logic Controller (PLC). When a host communication error occurs, you need to know what to do to fix it quickly and get back to work. The communication error is actually an easy fix that only requires a couple of basic hand tools and a very simple procedure. No need for professional servicing.

NTM’s service department provides on-call, in-house, or on-site support, as well as videos and articles to help you operate and maintain your NTM rollformer so that it works at peak productivity. In this article, we will guide you through the process of fixing a common communication error that often occurs with New Tech PLC. We’ll break down the steps to get your New Tech PLC back up and running smoothly.

Step 1: Identify the Host Communication Error

The first sign of a host communication error is usually displayed when you power up the machine. The screen will alert you that it cannot communicate with the PLC inside the control box.

Communication error displayed on controller screen.

Step 2: Gather the Necessary Tools

To resolve this issue, you’ll need the following tools:

  • Straight slot screwdriver
  • Philips screwdriver
  • 7/16″ or 3/8″ wrench (size depends on the model)

Step 3: Remove the Gas Strut

Begin by removing the gas strut that keeps the lid open. Be cautious, as this step can be a bit tricky. Apply outward pressure on the clamp while pushing the strut out. Ensure that you don’t lose the spring. Once removed, place the gas strut on the lid to keep it out of your way.

Removing gas strut
Removing the gas strut.

Step 4: Disconnect Power to the Controller

To guarantee safety, make sure the controller is disconnected from the machine. This ensures there is no power running to the controller. 

Step 5: Remove the Screws

There are 10 Philips screws holding the screen in place. As you remove them, be sure to keep track of both the screw and washer. The washer is essential for preventing condensation from entering the control box.

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Step 6: Lower the Screen

Once the screws are removed, carefully lower the screen to reveal the root of the problem. In most cases, the issue is with the communication cable that connects the PLC controller computer to the screen. This cable runs underneath a clamp and connects to the PLC.

Step 7: Access the Communication Cable

Gently pull the controller out of the way to access the cable. If there is a bracket blocking access, as in this version of the TLC, you may need to use a 7/16″ wrench to remove it.

Two types of communications cables.
Two types of communication cables, depending on the model.

Step 8: Reconnect the Cable

Reattach the communication cable firmly to the PLC. You should hear a solid click when it’s properly connected.

Step 9: Secure the Cable

Once the cable is in place, carefully reinstall the clamp. Apply downward pressure onto the cable without over-tightening it. Use a 7/16″ wrench to secure it in place.

Step 10: Reassemble the Control Box

Close the control box by reinstalling the screen and securing it with the 10 screws. Don’t forget to reconnect the gas strut as well.

Step 11: Test the System

Reconnect the controller to the machine, power it up, and test for the host communication error. If you reach the home screen without any errors, your New Tech PLC should be ready to run smoothly.

Finishing Up

Fixing a host communication error with a New Tech PLC is a straightforward process that can be accomplished with basic hand tools. By following these steps, you can quickly and effectively resolve this common issue, ensuring your PLC operates without a hitch.

For articles and videos on NTM machines, products, tutorials, and rollforming news, check out our Learning Center.

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