PLC origins: Where did PLCs come from? 40th anniversary timeline

PLCs have undergone 40 years of convergent evolution, according to an article in the upcoming September issue of Control Engineering. See a graphic with a timeline of PLC development, a market that went from zero to more than $1 billion in a decade. Link to the full story.

08/27/2008


Programmable logic controllers (PLCs) were more of a technology evolution than a startling discovery according to Control Engineering in the upcoming September North American issue. [See link below.] “The earliest robust, easily re-programmed industrial controller—which we know as the PLC—evolved nearly concurrently along three independent paths.”

 

Three tributaries converged to form today

 


Ball’s research for the

 

40th anniversary PLC article in Control Engineering

showed that PLC evolution involved five companies: Bedford Associates; General Motors Hydra-matic Division, Ypsilanti, MI plant; International Instruments Inc. (3I); Digital Equipment Corporation (DEC); and Struthers-Dunn Systems Division in Bettendorf, IA. He says that identifying the needs and early ideas first began to take shape in 1967. Documentation and actual building of prototype devices started in 1968, with early model deliveries and factory tests taking place in 1969 and ’70.
“Probably the most publicized early PLC development took place at GM’s Hydra-matic Division plant,” he says. “Several engineers there collaborated on a concept for what they called a‘standard machine controller.’ ” 
The GM engineers envisioned a controller to replace troublesome relay panels and provide a simpler interface between computers and machines.
Meanwhile, a second path was being pursued by Bedford Associates, a small New England company that today would be categorized as a control systems integrator. Bedford Engineers developed a controller to replace costly minicomputers and reduce programming time for various machine tool applications.
The third approach underway at the time occurred at the Struthers-Dunn Systems Division, which also had strong automotive ties and was well aware of relay and timer panel shortcomings.
Early on, the controller was known as the PC and publications such as the PC Insider popularized the designation. This was fine until personal computers arrived around 1980 and this office/consumer item stole the PC acronym. To avoid confusion, controls people reverted to a PLC designation — a term that had been registered by Allen-Bradley for their newer model controllers.“ Allen-Bradley has been quite gracious,” Ball says, “and has not attempted to restrict the use of the term.”
Shortly after the PLC debut, sales went from zero to more than a $1 billion in a little more than a decade.
C.G. Masi, senior editor
Control Engineering News Desk
Register here and scroll down to select your choice of eNewsletters free.

 



No comments
The Top Plant program honors outstanding manufacturing facilities in North America. View the 2013 Top Plant.
The Product of the Year program recognizes products newly released in the manufacturing industries.
The Engineering Leaders Under 40 program identifies and gives recognition to young engineers who...
The true cost of lubrication: Three keys to consider when evaluating oils; Plant Engineering Lubrication Guide; 11 ways to protect bearing assets; Is lubrication part of your KPIs?
Contract maintenance: 5 ways to keep things humming while keeping an eye on costs; Pneumatic systems; Energy monitoring; The sixth 'S' is safety
Transport your data: Supply chain information critical to operational excellence; High-voltage faults; Portable cooling; Safety automation isn't automatic
Case Study Database

Case Study Database

Get more exposure for your case study by uploading it to the Plant Engineering case study database, where end-users can identify relevant solutions and explore what the experts are doing to effectively implement a variety of technology and productivity related projects.

These case studies provide examples of how knowledgeable solution providers have used technology, processes and people to create effective and successful implementations in real-world situations. Case studies can be completed by filling out a simple online form where you can outline the project title, abstract, and full story in 1500 words or less; upload photos, videos and a logo.

Click here to visit the Case Study Database and upload your case study.

Maintaining low data center PUE; Using eco mode in UPS systems; Commissioning electrical and power systems; Exploring dc power distribution alternatives
Synchronizing industrial Ethernet networks; Selecting protocol conversion gateways; Integrating HMIs with PLCs and PACs
Why manufacturers need to see energy in a different light: Current approaches to energy management yield quick savings, but leave plant managers searching for ways of improving on those early gains.

Annual Salary Survey

Participate in the 2013 Salary Survey

In a year when manufacturing continued to lead the economic rebound, it makes sense that plant manager bonuses rebounded. Plant Engineering’s annual Salary Survey shows both wages and bonuses rose in 2012 after a retreat the year before.

Average salary across all job titles for plant floor management rose 3.5% to $95,446, and bonus compensation jumped to $15,162, a 4.2% increase from the 2010 level and double the 2011 total, which showed a sharp drop in bonus.

2012 Salary Survey Analysis

2012 Salary Survey Results

Maintenance and reliability tips and best practices from the maintenance and reliability coaches at Allied Reliability Group.
The One Voice for Manufacturing blog reports on federal public policy issues impacting the manufacturing sector. One Voice is a joint effort by the National Tooling and Machining...
The Society for Maintenance and Reliability Professionals an organization devoted...
Join this ongoing discussion of machine guarding topics, including solutions assessments, regulatory compliance, gap analysis...
IMS Research, recently acquired by IHS Inc., is a leading independent supplier of market research and consultancy to the global electronics industry.
Maintenance is not optional in manufacturing. It’s a profit center, driving productivity and uptime while reducing overall repair costs.
The Lachance on CMMS blog is about current maintenance topics. Blogger Paul Lachance is president and chief technology officer for Smartware Group.