Background Info

[maddog]

I'm new to this, so bear with me.. I am writing a book, part of which is about the PLC. I need some background info about the current market, for example, what percentage of today's controls market is PLC vs DCS? How has that changed over, say, the past ten years? Where is the PLC projected to be in the next five years? etc. Do any of you know of a good website or other resource to get this kind of information? Thanks for the help...

[Tom Jenkins]

Control Engineering Magazine recently had a market survey on this subject. It should be available online. Try http://www.controleng.com/

[Pierre]

Maddog... are you telling us that you're writing a book about something you know nothig about...

[maddog]

Thank you, Tom. I checked it out and did find a couple of items that were useful.

And, thank you, Pierre for your "constructive" comment. This topic is not the primary subject of the book.

General question: Looking at the control systems market as a whole, what share of the market does the PLC enjoy? As compared to the DCS, for example?

[SteveG]

PLC versus DCS market share? Well that would directly depend on the market. Power/Utilities are 99% DCS, Steel is 95% PLC, ect. The control system depends on the application, not DCS vs PLC.

my two cents

[Pierre]

You would also have an even harder time to differentiate PLCs and DCS.

Nowadays they are mixed and many users have a little of both, integrated.

[rsdoran]

In my opinion from the DCS we have, its a way now to add more devices(ie cost) to your needs. What DCS were and what PLC's are today its hard to formulate a real difference. IN the old days plc's were limited in function and motor control (stepper/servo etc) was done semi independently. DCS in those days allowed you to incorporate the PLC and the motor control system(s) using a single interface. That is still used today but with the features/options of plc's today that incorporate divers communication options and control capabilities of motor control systems it is hard to distinguish the differences in some cases.

What it boils down to is that today the PLC alone may be (and in many cases is) the DCS of yesterday.

[rsdoran]

Got to pay attention with this new forum when you make a post. All these hyar new fangled gidgets cant wait to jump on the screen.

[maddog]

Well said! I think I'm gonna like this forum. Thank you for your comments.

[Pierre]

One man deserving credits for his well tought analytical comments on futur trends and past situations within the controls industrie is Jim Pinto.

http://www.jimpinto.com/home.html

PS...What is your book about?

[maddog]

Thanks for the link to Jim Pinto. I'll go back and spend some time there - looks like a great source! My book is a primer on I&C design, aimed at newcomers to the field, and includes a chapter - really more of a section - on the control system. It will be published next fall. I don't get into a lot of programming detail, but I do spend a lot of time on the PLC/HMI. It's my first book. Having time to do proper research while working 60-hour weeks is difficult, so your help in pointing me to Mr. Pinto is appreciated. I should have joined this forum a while back. Thanks again.