The PLC Resource. Your PLCEdge!

  • Are you new to PLCs?
  • Would you like to know how they are used?
  • What about the different brands/types?
  • Are you afraid that you may not be buying enough or maybe too much for your application? 
  • Wondering what are the latest  developments? 

 Maybe just looking for info?

Well to start...what is a PLC?

The Programmable Logic Controller is not exactly a household name, but this device plays a huge role in our lives while hidden from plain view. 
These computers are special. They control and automate many of the things around you. From power plants to amusement rides to heat in your school to the amazingly fast assembly machines. They may also control and automate your house.
Have you been on a cruise ship lately? ...yes used there too.

They are all about "Inputs and Outputs"....
It is basically a specialized computer that connects to the physical world.  It does so through sensors, switches, buttons and other inputs. Briefly, based upon the state and values of the inputs and the program within it, outputs are turned on and off. Or within a range between on and off, to control things for hot, cold, slow or fast, etc...you get the idea?

The  Programmable Logic Controller was actually an improvement over old relays, cams and drums that would sequence machine operations. Changing machine operation would entail extensive rewiring of the sequence circuits.

When  Programmable Logic Controllers were introduced they were programmed in a format that followed the way the relays were physically wired. Now instead of having a team of electricians rewire the logic, the logic was in a sense was rewired through the software in the programming language of Ladder Logic.

As time marches on, it will automate more and more machines and processes. What is interesting is how will it evolve. Maybe you have heard of the Programmable Automation Controller (PAC)? This is the first significant evolution. It combines the robustness of the Programmable Logic Controller with the advanced networking, communication, and number crunching of a PC.

So read through this site. Discover the basics as well as:

  • advanced topics and new developments.
  • programming and applications.
  • training plus a evolving list of related topics.


PLCEdge's mission is to bring understanding, excitement and community to all things associated with the Programmable Logic Controller.

Most technical subjects appear intimidating and depending how they are taught remain discouraging.  Our goal is to change that.

Make everything as simple as possible, but not simpler.- Albert Einstein

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