Tips and Tricks for Legacy Hardware

By Danny Budzinski

For an engineer at my company, it is not atypical to be faced with outdated, legacy technology. A customer might come to us to upgrade a system that an intern did in the '90s. Maybe a company's engineers have built up a system over the past decade and need help configuring or adding more pieces to it. Or maybe a factory has a controller—made when its engineers were in middle school—that suddenly breaks down and needs to be replicated and replaced. Regardless of the situation, DMC engineers need to find the tools to connect to, read from, write to, and add on to whatever equipment someone might have.

Finding information on old industrial hardware isn't as easy as looking up technical support on your new Dell computer. There are dozens of legacy brands out there, but chances are that if you have something really old, it was made by Allen-Bradley, GE, Modicon, Omron or Siemens. All of these manufacturers are still around today, in addition to many others, and make a wide array of products from basic relays to PLCs and HMIs to other various controllers. Remember, though, that product lines can and have shifted owners many times through acquisitions and takeovers. This means even if something is labeled as a Modicon, you might actually have to go somewhere completely different to find the support you need.

A recent project I was involved with included replacing a Modicon-branded HMI. Modicon is currently owned by Schneider Electric (which might also be referred to as Telemecanique or Square D, which Schneider acquired 20+ years ago). However, this HMI actually was manufactured by Cutler-Hammer and simply labeled as a Modicon. Cutler-Hammer was acquired by Eaton in 1978, and reorganized in 2003. You can see how quickly this web gets unbearably complicated.
Here are some tips I have learned that will help your search:

1. If at all possible, get the exact part number of the equipment involved. A Google search on that alone often turns up forums (www.control.com and www.plctalk.net are good) where others have done the legwork of finding documentation, manuals and software for you.
2. Talk to anyone who might have been involved with the original project. It could be that there are documents, programming software and connection cables sitting around somewhere, maybe stashed in someone's desk or storage. 
3. Contact the original manufacturer. It might take a few phone calls to get the right technical support line, but be clear that you are looking for information on a legacy system. These companies pay engineers to answer questions, and, even if they are working for a different corporate master, these engineers sometimes are the same ones who built the stuff originally.
4. Contact the current manufacturer. This applies if a product line was sold off or if the unit was branded by a different manufacturer. A lot of times the engineers responsible for the product, or at least ones who worked with it when it was being made, will follow the sale. If you ask around for the right person, they usually can direct you to someone who is an expert on your hardware.
5. Don't be afraid to ask for software, programming cables, etc. The license might have cost $10,000 when it was released in 1985, but often the technical support engineer can at the very least get you a demo version or let you borrow some connecting hardware. Sometimes you get lucky enough that all of the software you need is old enough that they can give you a copy for free.
6. Talk to sales engineers at the company that sells the newest version of the product. Often they've had customers asking similar questions so they can tell you where to look and, again, you could be lucky enough that they sold the original product years ago and they know how to use it. Some sales engineers in the automation world just want to make sales, but a lot more of them are very, very helpful and want you to succeed.

This strategy has worked well for me over time, and I think that experience in finding answers for legacy systems is a strength of our engineers.

Danny Budzinski is a project engineer at system integrator DMC (www.dmcinfo.com) in Chicago.