HMI Panel Gone Black? What to Do When the Operator Panel Is Discontinued

SEO Title: Faulty or Discontinued HMI Panel? How to Find the Right Replacement

Meta Description: Is your Siemens, Schneider or Omron HMI panel faulty or discontinued? Learn what to check before buying a replacement and how to avoid unnecessary downtime.

Excerpt: A failed HMI panel can stop an otherwise perfectly functional machine. This guide explains what to check before buying a new or used replacement panel for an older automation system.

A production machine can be mechanically sound and have a PLC that works exactly as intended. Still, production may stop because the operator panel suddenly goes black.

On older machines, the situation can quickly become difficult.

You identify the part number, search the manufacturer's website, and discover that the model has been discontinued for years.

A newer HMI series may exist, but that does not necessarily mean it can be installed directly.

An HMI panel is not just a screen. It usually contains a project with screens, alarms, recipes, communication settings and operating functions developed specifically for the machine.

That is why it makes sense to think carefully before ordering the first model that looks similar.

Start With the Full Part Number

The first step is to identify the panel correctly.

Take a clear photo of the nameplate on the back and record the complete manufacturer part number.

For example, a Siemens SIMATIC panel may have a number beginning with 6AV..., but the same principle applies to Schneider Electric, Omron, Allen-Bradley and other manufacturers.

Record details such as:

• Manufacturer
• Full part number
• Model designation
• Hardware version
• Serial number
• Supply voltage
• Any revision or version information

Two panels can look almost identical from the front while still being different products.

The exact part number should therefore always be the starting point for your search.

Do You Have a Backup of the HMI Project?

This is one of the most important questions.

If the old panel is completely dead, it may be impossible to retrieve the project from it.

If your company has the original backup, the situation becomes much easier.

The backup may be stored:

• with the maintenance department
• on an old engineering PC
• with the machine builder
• with the system integrator who programmed the machine
• on a company server or backup system

On older machines, the problem is often that nobody knows where the files are anymore.

That is why documentation should be part of the spare-parts strategy. Having a spare HMI panel on the shelf is of limited value if the required software and project files are missing.

An Identical Panel Can Be the Fastest Solution

When production is stopped, the technically most modern solution is not always the economically best one.

Imagine a machine with a 15-year-old HMI panel.

The manufacturer offers a modern successor, but migrating to it requires:

• conversion of the HMI project
• new engineering software
• changes to screen layouts
• verification of PLC communication
• changes to the panel cut-out
• testing of all functions

That may absolutely be the right long-term solution.

But it is not necessarily the right solution at 10 a.m. on a Tuesday when the production line is down.

If an identical original panel can be sourced, it may be far quicker to install the same model and transfer the existing project.

This is exactly where discontinued HMI operator panels can be highly valuable.

Can a Newer HMI Panel Be Used?

Often, yes.

But the word replacement should be treated carefully.

A manufacturer may recommend a newer model as the successor to an obsolete panel without it being truly plug-and-play.

Check at least the following:

Physical dimensions: Does the new panel fit the existing cut-out?

Communication: Does it support the same protocol and interface as the PLC?

Software: Can the existing project be migrated to the newer engineering platform?

Functionality: Are scripts, recipes, alarms and special functions still supported?

Power supply: Are the voltage and electrical requirements the same?

On simple machines, migration may be relatively straightforward.

On custom-built equipment, it can quickly turn into a small engineering project.

New, Unused or Used HMI?

When the original model has been discontinued, it is often available only on the secondary market as unused surplus stock or used equipment.

An unused panel can be attractive, but keep in mind that new old stock may still have been stored for many years.

A used original HMI panel can also be a practical option, especially if the goal is to keep an older machine running until a planned modernisation.

When buying used HMI panels, look for:

• damage to the display
• heavy scratches
• faulty buttons
• discoloration
• damaged connectors
• cracks in the housing
• signs of moisture or corrosion

On touchscreen panels, touch functionality is naturally especially important.

Remember Cables, Adapters and Memory Cards

Some HMI replacements fail because of something as simple as a missing cable.

Older systems may use specific programming cables, communication adapters or memory cards.

If the machine is critical, these should be included in the documentation as well.

It can be a good idea to store the required programming equipment together with the spare part, or at least document exactly what is needed.

A spare HMI panel is not very useful during a breakdown if nobody can load the project onto it.

Consider Buying the Spare Before the Panel Fails

If your company operates several older machines with discontinued HMIs, it may be worth identifying them before the first failure occurs.

A simple list can be enough:

Machine	HMI	Part Number	Backup	Spare
Line 1	Siemens SIMATIC	6AV...	Yes	No
Packaging Machine	Schneider	HMIG...	Yes	Yes
Conveyor System	Omron	NS...	No	No

Prioritise panels where:

• the machine is critical
• the HMI model is discontinued
• there is no simple modern replacement
• lead time for original parts is uncertain

A spare panel costing a few hundred or a few thousand euros may be cheap compared with a full day of lost production.

What If You Cannot Find the Panel?

Start by searching for the exact part number.

Avoid searching only for terms such as Siemens HMI or Omron touchscreen. That usually returns too many irrelevant results.

Also try the part number with and without spaces or hyphens.

Specialist industrial suppliers may also have components in stock that are not yet listed online.

KLJ Trading continuously stocks new, unused and used industrial automation components, including HMI panels, PLC components, power supplies, sensors, relays and drives.

If you need a specific panel, search the manufacturer part number on kljtrading.com.

If you cannot find it, contact KLJ Trading with the manufacturer, full part number and preferably a photo of the nameplate. We can then check current stock and possible sourcing options.

The Best HMI Strategy Starts Before the Screen Goes Black

An older HMI panel can operate without problems for many years.

That makes the risk easy to ignore.

But if the panel is critical to machine operation and has already been discontinued by the manufacturer, it is worth spending half an hour assessing the situation while the machine is still running.

Find the part number.

Find the project file.

Check whether the model is still available.

And decide whether keeping a spare on the shelf makes sense.

It is much easier to solve that problem on a quiet Friday morning with a cup of coffee than on Monday morning with a production manager standing behind you asking when the machine will be running again.