Hurray! A new Fundamentals course written and narrated by yours truly has just become available - The Fundamentals of Industrial Control Processing...
Hurray! A new Fundamentals course written and narrated by yours truly has just become available – The Fundamentals of Industrial Control Processing…
Actually, I have something of an interest in control systems in general, because my degree was a BSc in Control Engineering (this was a core of math, with sub-topics in electronics, mechanics, and hydraulics-fluidics).
Also, I come from Sheffield, England, which – for hundreds of years – was famous for its iron and steel production; also for its cutlery (flatware) and silverware. Just to give you a sense of where I’m coming from, I have a friend whose family owned a magnet factory in Sheffield. This company was established more than 200 years ago in 1783 (the year America officially gained its independence as a country).
I once visited this factory. It was very “Charles Dickens” if you know what I mean. The master’s office, which was upstairs, was lined with wood and was very pleasantly appointed. Also, the master’s desk was on a raised platform so that he looked down on you and appeared larger than he actually was (think “Scrooge” from A Christmas Carol).
The factory itself, which was located on the ground floor, was much less salubrious. It contained lots of machines, each of which had a human operator. Some machines were used to cut different-shaped rods or bars to the required lengths. Others were used to bend the rods or bars into the required shapes. There were foot-controlled hammers and all sorts of things.
The point is that this was hard, dirty work that was time-consuming, error-prone, costly, and inefficient. It was also dangerous, because when you are doing the same repetitive thing hour after hour, day after day, week after week, and month after month, your mind tends to wander and accidents happen.
Interestingly enough, my friend told me that – even though they were a relatively small operation in the scheme of things – their magnets were used around the world. They still occasionally received orders from distant climes, such as one he showed me that had just come in from a railway company in India requesting a certain type of magnet that was used in a locomotive that was more than 100 years old. The factory still had the original specifications and they made a couple and sent them off. Color me impressed!
A factory in Sheffield, England circa 1910
(Courtesy the Ken Hawley Collection Trust)
Now, contrast this with a modern factory jam-packed with automatic machines and robot trolleys scurrying around retrieving materials and parts from the store, feeding them to the machines, conveying parts and assemblies from machine to machine, and taking the finished products and storing and/or shipping them. If we contrast these two scenarios – the old hand-operated magnet factory with its modern automated cousin, it’s easy to see the advantages of Industrial Control…
For myself, I’m always interested to know where things came from. Control systems in general – and industrial control systems in particular – date back to antiquity. Originally all such systems were mechanical in nature. The classic such system that immediately springs to my mind is the centrifugal “fly-ball” governor, which was used to control the speed of an engine and prevent it from racing out of control.
Did you know that the first such governor was designed by James Watt as far back as 1788. The device shown above is used to control a steam engine, but later these were also used to control internal combustion engines and variously fueled turbines.
The idea is that – in addition to its main task – the engine also causes the governor assembly to spin. Centrifugal force causes the balls to move outwards and upwards against gravity. If this motion goes far enough, it causes the lever arms to pull down on a thrust bearing, which moves a beam linkage, which reduces the aperture of a throttle valve, thereby controlling the rate of the working-fluid, which would be steam in this example or fuel in the case of an internal combustion engine.
As an interesting tidbit of trivia, the first formal analysis in the realm of what we now know as control theory was performed on the centrifugal governor by the physicist James Clerk Maxwell in 1868. This described and analyzed the phenomenon of "hunting", in which lags in the system could lead to overcompensation and unstable behavior. And this all eventually evolved into my degree in Control Engineering (I just thought I’d drop that in to tie everything neatly together).
But we digress… somehow you’ve managed to lead me odd into the weeds again … just wind me up and watch me go…
The point is that modern industrial control systems are phenomenally clever and do all sorts of things. We have Programmable Logic Controllers (PLCs), Programmable Automation Controllers (PACs), and Embedded Single Board Controllers (SBCs).
In turn, PLCs, PACs, and Embedded SBCs, may use a variety of electronic components to perform their processing magic, including microprocessors, microcontrollers, digital signal processors, ASICs, ASSPs, SoCs, and … wait for it, wait for it … FPGAs.
Yes, of course you want to know more, but I have to return to ponder my Heath Robinson Rube Goldberg Steampunk Computer
project, so instead of my continuing to waffle on here, please feel free to visit The Fundamentals of Industrial Control Processing
course and let me know what you think (also tell all your friends about it, because this little scamp took a lot of effort to create, so now I want to get the word out that it’s arrived [grin]).