Artificial Brains: PLCs

Automation: a term close to science fiction, which calls to mind modern Companies and fast, efficient assembly lines, where intelligent machines working in perfect harmony assemble components, create finished products, package them, and group them for shipping…

...but we need to linger a while, and with great attention, on one of the terms we just used: it is a very heavy word, and although we use it lightly in common speech, we must not forget what an actually enormous thing it represents.
We called those machines... intelligent. And this is, of course, gross exaggeration. What we did say that was true, though, is that looking at them function, it is truly hard not to think that they actually are intelligent: and for an explanation of this trick, or better, of the technology behind this perception, we went and asked ASCON, who’s been designing and selling the little brains which are the basis for automation: PLCs.

PLC is of course an acronym, and it stands for Programmable Logic Controller: the first approximation we could give to describe it, which also happens to be quite correct, is calling it a computer. But there is an important difference: a computer is designed and built to function in a standard environment, like our home or our office, and it normally receives inputs from a keyboard or mouse, returning outputs on a monitor or a printer. On the other hand, a PLC is born to operate in a definitely more specific field, but also in far different conditions and with very different purposes. This is why the input and output channels on a PLC are far more than a generic computer’s and they do not connect to just monitors and printers, but to sensors, electric motors, hydraulic cylinders, in a word to the “sensory organs” and to the “muscles” of that complex “organism” that an industrial machine is; still for this reason, a PLC has special insulation to protect it from the electrical disturbances which can abound in the machine where it is mounted, and which pose no threat in our offices; and once more for the same reason, a PLC is born, differently from a computer, to resist a far wider range of temperatures , and far harsher physical impacts, such as vibrations and hits, than the ones a home computer will likely ever face.

Having thus made clear how a PLC is a more robust and more specialized computer than the one we are, for example, using to read this article, an explanation remains to be given for the reasons to decide to implement one, and the advantages deriving from such decision. A PLC has a precise field of application: its purpose is automating, with a digital tool, the logic operations which were traditionally managed, in industrial machinery, by complex, large relay systems (it was, in fact, to find an alternative to those relays that General Motors, in 1968, required the design of a new kind o system) which needed one- by one manual reconfiguration whenever productive needs changed. The passage between an electromechanical system and a software based one is actually just in the ease of programming and reprogramming, which allows to implement automation also where the number of finished products could make traditional or complex systems anti-economical. Which brings us back to where we started, at our initial image of quick, efficient Companies, where “intelligent” machines (and we now know the extent and manner of such intelligence) harmoniously create finished products.