By Jeremy Pollard, CET
THIRTY YEARS AGO, the PLC was brought out of the lab into the cruel world by its father, who, by my recollection of history, was Dick Morley. His company was called Bedford Associates Inc., and shortly thereafter he started a little company called Modicon. What an industry that followed!
Ive been part of the industrial automation industry for all but two of those 30 years. There are many people whove had a profound effect on our industry that you probably dont know about. People who, for the most part (and Im guessing many of you dont have my long-in-the-tooth relationship with automation and its heroes), have slipped into the obscurity of old news.
These people sought to fill an automation void that needed saviors and innovators in order to give the user what they needed, at a time when these customers didnt know they needed it.
How much of a problem was that? I was an Allen-Bradley sales rep in the late 70s, trying to convince customers that PLCs were good for them. Most of the time it was a hard sell.
By the early 80s it got a little easier. Customers couldnt get enough. They spent a gajillion dollars on training, simulators and programming panels, and hardware-based operator interfaces. It was all very vendor-specific though.
Over the next few columns, I want to introduce you to some of these heroes who, in my opinion, changed the way we do business in our chosen field. Its helpful to recognize where weve come from, and who better to lay it out for you than an old-timer like me?
It was, and still is interesting, frustrating and exhilarating that I chose to make my career in automation.
In my first few years with A-B, I was introduced to the many facets of motor control and automation. When I went to school, I was working with low-voltage logic circuits, so when I got involved with 600 V, I was really nervous. Nevertheless, I learned to respect the power of what we can do with such a resource.
In 1977, I was introduced to a number of companies including General Motors, which was using those new-fangled PLCs. They had room upon room of climate-controlled electronics, with very expensive seven-inch CRT programming panels, sealed keyboards, and a cassette recorder for backup. Try installing a 500-rung program with that! There was no documentation on screenit all had to be done manually.
As a sidebar, I was tasked to prepare a demo program for the new Basic module that Allen-Bradley was introducing. I wrote the 42K program in ASCII mode, printed it on a Texas Instrument Silent 700, 300-baud serial printer with thermal paper, and saved the programs--as a whole, and not incrementally--on a cassette recorder.
Troubleshooting was an art and, because of the lack of resources, lots of code was added to fire messages to displays so someone had a clue what was going on.
In the early 80s, the hardware interfaces began to allow graphical representations of processes. TI provided the CVU product, A-B had the Advisor, and some third-party solutions such as Westhead Graphics started to provide some insight into the processes that were using PLCs as a control engine. Does anyone remember Modvue?
Xycom had a CPM operating system-based computer that for a measly $20,000 could provide printed documentation to your electricians for troubleshooting. It was messy though--real messy. The user interface featured push buttons. Handy for the Pickaroons in the lumber industry, but bulky for a transfer line that required 200 buttons at an operator desk cluster. Where was that stop button?
The PLCs were closed systems, and their developers fought tooth-and-nail with the process DCS systems for a piece of the automation pie. With the introduction of analog into PLC systems in the early 80s, a new market was available for the PLC controlled process, but lacking a few of those tools that the DCS crowd had.
Again, in my grizzled opinion, there were a couple of monumental things that happened to change the course of machine automation history: the IBM PC (1981), and Microsoft Windows 3.0 (1989). All hell broke loose because of these two events and gave rise to the innovators I want to tell you about in these coming months.
By the way, if you have a hero that you think belongs here, get in touch and tell me why. This will be fun.
Jeremy Pollard, CET, has been writing about technology and software issues for many years. Publisher of The Software User ONLINE, he has been involved in control system programming and training for more than 20 years. Browse to www.tsuonline.com or e-mail him a email@example.com.
By Jeremy Pollard, CET