2007-03-20 08:18:15 · 2 answers · asked by Anonymous in Science & Mathematics ➔ Engineering
Programmable Logic Controllers (PLCs) popped up in the 1970's to replace hardwired relay logic industrial automation with a computer controlled system in General Motors plants. It was designed to interface with equipment that was controlled by relays to reduce the amount of changeover to a new system. The old relay based system had to be rebult everytime you changed your automated process. With the PLCs, you could changes whatever you needed with a few commands. The first software gave a representation of Ladder Logic diagrams, so that the plant electricians could use the systems easily and they did not have to learn any actual computer commands.
2007-03-20 08:28:30 · answer #1 · answered by dancerman_77 2 · 2⤊ 0⤋
My first computer had 64k memory ,I thought I had a good one.
2007-03-20 15:26:24 · answer #2 · answered by JOHNNIE B 7 · 0⤊ 3⤋