Does anyone remember when the first PLC was sold? I know that "electronic controllers" were available sometime in the 1960's, and the first microporcessor chip was built around 1970, and the first "personal computer" was available in kit form in 1975, but when was the first Programmable Logic Controller made, what brand was it, and how much I/O did it have? I should remember this stuff, but the older I get, the foggier it gets.