Knowledge Base
History of the PLC

I came across something interesting while checking out our Google ratings (#1 spot under “programmable logic controllers” plus listings on several subsequent pages!). The thing I discovered is the history of the PLC. You can find it at http://www.barn.org/FILES/historyofplc.html

This is a verbal history of the very first PLC, narrated by its chief architect, Dick Morley. It’s well worth a look, and while you are there look around the other stuff on the site. What struck me about it was the pre-occupation with making a box that was reliable. I remember those days (1968-ish) quite well myself. I was an even younger 🙂 engineer then, and involved in a couple of ways with selling minicomputers, mainly the PDP8 and a bit later the original Nova. The machines cost something like A$25,000 (that was about 5 year’s pay to me at the time), and came with a 3 month warranty. That’s right, 3 months! The rationale was that the semiconductor components exhibited “infant mortality”, so if it was going to fail it would be within the first 3 months. After that you were on your own.

So, is SPLat a PLC? By Dick Morley’s standards, no it’s not. SPLat is an embeddable board level controller aimed at OEMs. We see our customers as being product makers who need a controller in their product. Mr Morley’s programmable controller was intended for factory automation, which is a quite different thing. Dick Morley’s product came in a cast iron case. Ours comes as a bare board, ready for you to integrate into your own product packaging.

Anyhow, take a look at the site. It’s a fascinating read.