By Ken Ball
Programmable Logic Controllers (PLCs) were more of a technology evolution than a radical development. A noteworthy aspect about the origin was that quite similar concepts were pursued by three separate companies—nearly concurrently but unknown to each other. Part 1 in a series of four articles about the history of the PLC.

Read the FULL ARTICLE here:
The Dawn of the Programmable Logic Controller (PLC)

Source: Automation.com