This Blog is dedicated to talking about about PLC's or Programmable Logic Controllers. Programmable logic controllers are simple computer systems that controls I/O or Input and Outputs. This I/O is typically devices like switches, buttons, sensors, relays, etc. PLCs are used to control things such as industrial machines, factories, assembly lines. They are programmed using typically expensive software and then downloaded to the processor. The programming code looks like a graphical version of assembly code.