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The Arduino UNO

Arduino – a PLC buster?

Can the Arduino be used as a PLC?

One of the more common questions found on the forums is whether the Arduino could be used as a PLC? (Programmable Logic Controller).

The simple answer is a yes. However there are criteria to remember – operating temperatures, line noise, safety circuitry and feedback control. Of course you will need to supply this piece of equipment with a compliancy certificate. Unfortunately in most cases we cannot cater for this because the home builder may lack the skill set to produce a product which could operate reliably in an extreme environment. The PLC from Siemens, Schneider and many others can. There is another thing as well – instruction set or as in the case of PLCs, Ladder Logic.

The Arduino UNO
The Arduino UNO – photo credit 1sfoerster

My first ‘big’ attempt at writing a software application allowed the user to select a storage drive, save all the URLs of the music and video tracks which allowed the user to search and play the track of his choice. After 300 lines of code I had this masterpiece up and running. One little bug later I could not trace out where the problem was because it lacked all the bells and whistles that ‘real’ programmers use – comments. I rewrote the entire program, another two days wasted using functions and comments.  50 Lines of code. PLCs originated because of the difficulties the technical people had in rewiring the ‘system’ when changes had to made. Does ENIAC spring to mind? With PLCs it is my way or the highway – Modicon (the original PLC with Dick Morley) designed PLCs to be easy to program and service.

The Arduino can and does everything the PLC can do but it was not only designed to automate machines. So what then?

The Arduino’s strongest virtue is the ability to educate people in microcontrollers – I think, like Turbo Pascal which has it’s own set of merits it has proven to be one of the greatest gift to scholars. Microcontrollers cannot be taught by theory alone – we are not all that clever.  Arduino has a tremendous following as well which makes it all that more popular. Price wise it’s relatively cheap – I would say very much in comparison to Raspberry Pi and not the Intel NUC. Different strokes for different folks? Not at all – I am sure there are many Arduino lovers that have hooked up to the Raspberry Pi. Education goes a long way.

Arduino has a very powerful website which connects with anyone interested in microcontrollers, what you can do, what you cannot, the strengths, the weaknesses. Arduino can do anything your mind wants it to do. The face of the future.

Besides the Arduino website look at


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