A Retrospective on 35 Years in Automation
Having recently celebrated my 60th birthday, as well as 30 years with Matrix Technologies, I thought the readers might just be willing to indulge me in a bit of reminiscing about the changes I’ve seen in the automation business. Depending on your perspective, you may say, “Hey, I remember that!” or ”Dang, this dude is old.” Either way I hope you’ll enjoy the trip.
When I first started at Matrix in 1984, we had one computer. It was a shiny new IBM XT with a 10 MB (that’s 10 million bytes, not a typo) hard disc that would store all the files you might ever need. It had two 5¼-inch floppy disks for transferring information on and off the hard drive. We had a sign-up sheet posted near the computer workstation where you could schedule your time (in 30-minute increments) to use this marvel of technology. Today it’s pretty common to find a disc of 2 terabytes (TB), or 200,000 times the XT.
The first PLC project I worked on used a Reliance Automate 32 processor. It had many advanced features, like the ability to write user functions in BASIC, two-point input/output (IO) modules that were remove-under-power. It used a Star-Link cassette tape recorder to save and load programs. Programs were typed into memory directly for testing and operating, based on your handwritten program notes. Don’t forget to save it to the tape when you are done!
In the early years, Modicon was the market leader in programmable logic controllers (PLCs), and had the first redundancy unit allowing two PLCs to be used to keep the process running in the event of failure of one of them. The Modicon 584 was approximately 2 feet wide x 2.5 feet high x 18 inches deep, all made of metal and pretty heavy. The redundancy unit was the same size, so one could end up with a huge panel just filled with processors. Left a lot of space for new PLCs once we were able to retrofit these years later.
Modicon also had one of the first color graphic touch display units (Modvue), to show color screens representing the process and allow screens to be built with software. This unit was also huge, with the processor in a similar box to the 584, plus another color TV monitor that plugged into it. I still recall doing a demo of this new technology for Bethlehem Steel. The Modvue would reboot every time the elevator down the hall opened its doors. Made for a very interesting sales pitch!
GE Series Six PLCs were another industry workhorse, with heavy rugged chassis. Quite a few are still out there. I recall having to program the analog outputs to multiplex signals to the output devices. We started up a machine that had a typo in the output routine, so that every eight scans of the PLC, the output card sent a full-scale signal to a hydraulic cylinder on the machine. This caused the cylinder to stroke with such force that it literally tore the machine out of the concrete and proceeded to walk across the plant floor. We were all working back in the control room when a panicked operator ran through the door making us aware of the problem. E-stop circuits worked well (fortunately) and the machine and PLC program were fixed the next day.
Remember when you had to keep track of the central processing unit (CPU) memory you were using in your program?
- Generate a printed reference so you could mark off what registers you used.
- Keep track of what type of memory (retentive, volatile, or global).
- Different instructions used a different number of words. Math for example, often needed two consecutive words (and three for timers); otherwise it would overwrite the next address.
- Hope you didn’t lose track or spill coffee on the pages.
So nice to have user-defined data types and automatic memory allocation these days!
Later models of the Modicon 884/984 series included 800 series IO. These had razor-sharp contact pads on the modules for insertion into the wiring base. On a startup I managed to remove a module and drag those contacts across my fingertips. I had to walk around with my hand in my pocket until the bleeding stopped.
Serial communications were a staple of device-to-device information transfer. These used a dedicated cable between the two devices and required compatible data rates and formats, with very little standardization in the industry. These links often took a bit of programming to get working (and a protocol analyzer). Once up and running, they were pretty rock solid, albeit slow compared to Ethernet, for example. A rate of 9600 baud (bits/second) compared to one billion bits/sec now. On the plus side, serial communications don’t need an IP address, are not prone to hacking, and don’t require any special switching hardware. They had their place (and still do) for low-speed device integration.
In the days before Microsoft took over the operating system (OS) market, there were a variety of choices depending on the hardware used. This allowed a specialization toward industry and manufacturing that is lacking with Windows. The closest thing we have today is the configurability of Linux. On the down side, each different OS required specialized knowledge and was generally incompatible with the others. Some of the old operating systems included VMS, Unix, DR DOS, OS/2, CPM and many more. Are we better off with Windows? Perhaps, but the cyber criminals make good use of this standardization and interoperability of Windows. Just sayin’.
While some of these war stories might give the wrong impression, what I remember most fondly in my work experience are the many dedicated and intelligent people I’ve worked with over the years. This includes my coworkers, customers, electricians, operators, support staff and other team members who all worked together to accomplish the goal of getting the project running. This was often accomplished under tight deadlines, cost pressure, lousy food and long hours, while missing family events and holidays. There is nothing more satisfying than going from an initial need to a well-operating unit. While there is a lot of sweat and tears along the way, one forges friendships that last a lifetime. My heartfelt thanks to each and every one of you.
Matrix Technologies is one of the largest independent process design, industrial automation engineering, and manufacturing operations management companies in North America. To learn more about our industrial automation capabilities and manufacturing process control solutions, contact Charlie Sheets, PE, Senior Consultant.
© Matrix Technologies, Inc.
Tags: Charles Sheets, PE / Industrial Automation Engineering / Legacy Upgrades / Manufacturing Operations Management / Manufacturing Process Control / PLC / Upgrade / GE / IBM / Microsoft / Modicon / Modvue
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