The very brief fascinating history of electronic controllers!
Lets face it: Computers are impressive. Very impressive. But it is also true that most people became blasé about the performance we have today.
Digging into the history of computers all the way back from Gottfried Leibniz who refined the binary numbering system in the late 1600's, one cannot else but to appreciate what has been achieved.
Although in my opinion a waste of resources, computer games probably is the best demonstration for the ignorant masses of where we are today.
Electronic controllers on the other hand, are simple devices. It is probably the closest modern devices that resembles some of the early digital computers.
To program controllers, is quite a bit different from programming a modern computer with memory and processors all in the giga warra warra range.
Many controllers still works in the single digit megahertz range and have kilobytes of memory. Yet the things one can do with it, is mind blowing - especially taken into account the relatively low power of the processors.
Few people are aware of the crucial role Mainframe computers still plays today. The Mainframe platform originated in the 1960's and has a very unique hardware architecture compared to the blade servers which are now common. The two are however not even closely of the same family of computers and to refer to a blade server as a Mainframe, is nothing less than blasphemous.
The only manufacturer that still offers the mainframe platform is IBM and the latest hardware is just about emulators of the old units it replace. Mainframe systems still runs some of the most most crucial functions we have today. Financial transactions, airspace monitoring systems and nuclear launch platforms are still served by these dinosaurs - and for good reason. There really is nothing to replace it with. That is how well engineered it was. Did you know that valves are still manufactured today? Intriguing thought...
Controllers are in a way similar to the old mainframe computers. Compared to anything else they seems to be slow, simple and limited in terms of programming. That is all true, but like mainframe computers, controllers are very efficient.
This efficiency is achieved in two main ways:
The father of most of the generations of controllers we get these days, is the Programmable Logic Controller - in particular the Modicon 084 which not only delivered on the hardware, but introduced Ladder Logic as software language. This made it immediately possible for many engineers of that time to understand and adapt to the system.
This platform was also designed in the 1960's and like the mainframe computer it just got it right, all the way from the hardware to the programming.
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The Modicon 084 could already at that time, handle 128 outputs as well as 256 inputs from a single main processor all via expansion modules - few if any controllers outside the PLC family can do this today. Relays could be switched in less than 17ms. Yet it was done with 4K of memory and a processing speed somewhere in the low kilohertz range. This is rather hard to imagine, but this is what a good design does.
At that time, it revolutionized the automation of the General Motors factory as it replaced enormous banks of relay circuits with one comparatively tiny box. The really big advantage was that any changes could be re-programmed. No rewiring needed any more!
Probably one of the prettiest examples of what a PLC can do - for me at least - is a bottling plant. It is engaging to watch how bottles are sorted, placed, screened and eventually ends up on the many lines where it runs at blistering speeds through multiple lines and gets filled and capped without spilling a drop.
From this PLC, other generations of controllers sprouted which took a completely different direction. The basics however, are the same.
The drive for more automation will only increase and whether it is good or bad, is another discussion. The point is, it happens and controllers makes it possible.
Without controllers, there will be no factories making processors for controllers or computers. It really is one of the core building blocks of industry today.
If you are an engineer or technician, it would be foolish not to be as skilled with controllers, as you are with the use of your computer.
These devices are indeed fascinating - even more so is the fact that the backbone that was established over 50 years ago, still serves industry today. There was no major changes. Yes some things got faster and gained capacity, but it still runs on Ladder Logic and Modbus over RS-485.
On the humble end of the scale, 8-pin 8-bit controllers are still used by the millions to perform everyday tasks in our appliances or otherwise.
Don't judge a chip by it's number of legs!
If you interested in entering this field, Delta Solar offers an introductory 2-days CPD course on electronic controllers.