Don’t put off upgrading your programmable logic controllers

Oct. 28, 2021
When it comes to programmable logic controllers (PLCs), a proactive approach to maintenance and upgrades is almost always better than a reactive one.

“If it ain’t broke, why fix it?”

It’s a question we’ve all heard before, but when it comes to older programmable logic controller (PLC) installations, it’s not an answer you want to find out the hard way. While some components can be found and purchased online, if your primary source for replacement parts is a site like eBay or, it’s likely time to upgrade your system.

3 signs it may be time to upgrade your PLCs

A proactive approach to maintenance and upgrades is almost always better than a reactive one, but plant managers and corporate decision makers are often juggling numerous variables and putting out multiple “fires” at any given time.

So how long is too long to risk skating on the thin ice of your aging PLC technology? Common warning signs include:

  • You are running Windows 7 or older — Microsoft stopped supporting Windows 7 on January 14, 2020. If your PLC is still running the Windows 7 operating system, it is definitely time to upgrade to Windows 10 along with your HMI software to ensure your system is not vulnerable to cyberattacks. 
  • Your installation is at least 10 years old — If your PLC is more than 10 years old, you are likely missing out on opportunities to increase energy efficiency such as advanced compressor sequencing, floating head pressure control or other efficient control strategies.
  • Historical breakdowns — If your PLC has already shown signs of breakdown such as processor or I/O module faults or failures, they are likely signs of a pending breakdown. Partial upgrades are more budget-friendly than full upgrades and can be done with little to no downtime.

While every system and scenario is different, a planned and methodical approach to the migration process will always be more cost-effective than an emergency upgrade that requires costly, unscheduled downtime at your facility.

Of course, there are countless aspects of a food or beverage plant that are constantly vying for energy, budget and attention — so why should updating your PLCs be higher on your priority list? Let’s consider a beef processing plant that took that gamble — and lost.

When procrastination can cost you double

This particular beef facility was utilizing PLCs that were 14 years old. When its system suddenly failed, the plant lost several hours of valuable production time while our team switched into “rapid response” mode. We had to install temporary switches and wire them to every valve group output so that our refrigeration technician could operate the plant’s air units while we designed a new panel on the fly.

Stellar staffed the plant 24 hours a day, 7 days a week, for a month in order for our team to engineer, program, install and commission a new upgrade, build and install a new panel, and recommission the new system. The necessary but expensive last-minute project cost about twice as much as it would have had the facility budgeted and planned for the upgrade.

You simply don’t want to find yourself in this situation. At the end of the day, buying a little extra time for an inevitable PLC upgrade isn’t worth doubling your investment and disrupting your plant’s operations when the decision is forced upon you due to a system failure.

So how can you strategically plan for this crucial upgrade and identify what that investment might look like? A custom audit can help reveal the strengths and weaknesses of your automation system in order to best plan for the road ahead. 

Brad Smith is the director of business/product development with Stellar. He has extensive automation experience in several areas, with expertise in industrial and recreational refrigeration systems, large HVAC applications as well as heat recovery. His combined field experience along with proven team management skills allows Stellar to develop and deliver the cutting edge, best of breed automation systems and customer experience. Brad has nearly 30 years of industry experience. Stellar is a fully integrated firm focused on planning, design, pre-construction, construction, refrigeration, mechanical & utility, building envelope, and total operations & maintenance services worldwide. Visit the company's blog at or learn about its projects at

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