Mike Bacidore is the editor in chief forĀ Control DesignĀ magazine. He is an award-winning columnist, earning a Gold Regional Award and a Silver National Award from the American Society of Business Publication Editors. Email him atĀ [email protected].
In May, I had the unique privilege of visiting with Dick Morley, largely considered to be the father of the PLC. Now in his 80s, Morley is a treasure chest of stories and insights. But his mind is much more than a collection of memories. Like the universe itself, itās still expanding and revealing its mysteries to those who are fortunate enough to listen.
While heād much rather discuss the intricacies of quantum entanglement, Morley slowed down long enough to explain how the programmable logic controller (PLC) came into existence. And, as Morley tells it, the development of the PLC followed a path that was as independent as it was inevitable.
āAllen-Bradley and General Motors were interested in something that solved the problem,ā explained Morley. āBut we didnāt follow the spec. The reason it works is because itās so simple. I used relay logic. The programmable controller is a box of relays. I just built oneāsimplicity. We built them, and we didnāt know we were building them. Toyota credits me with making them a big company because the Japanese at that time couldnāt understand American software.ā
Also read: The father of the PLC explains its birth
The original PLC, built by Morley and his colleagues at Bedford Associates, had only four outputs. āMathematically, you only need three, but I put four in,ā he said. āThen guys started making an infinite string, which is the wrong way to go. Albert Einstein says to make everything as simple as you can, but no simpler. The way to make a product is to take stuff out, not to put stuff in.ā
Once the first PLC was given the green light, Morley wasnāt sure where the money was going to come from for production. He found it in General Motorsā maintenance allocation. āThey had an infinite budget to fix the automation line, whatever the cost,ā explained Morley. āSo, we used the repair and maintenance budget to build them. We made them, and the thing took off like a bandit. We couldnāt keep up.ā
The PLC is a fixed object, said Morley, and it tends to be open source. āMost engineers want a solution thatās the same size as the problem,ā he explained. āThe programmable controller is a solution for all problems.ā
If you want to create software or a product thatās a ākeeper,ā like the telephone handset, you canāt just create one solution that fits the problem, said Morley. āThe programmable controller is not just a solution; itās several big solutions,ā he explained.
Always looking to the next problem, Morleyās mind continues to expand. Not even Einsteinās special theory of relativity can explain how it can be in so many places at once. But the manufacturing industry is still thankful that Morleyās mind was in Bedford, Massachusetts, in 1968 when a few relays were put in a box and the PLC was born.