plc

kalyan48 · Oct 22, 2008

what is the definition of PLC?

rdrast · Oct 22, 2008

http://www.acronymfinder.com/PLC.html
Pick one.

geniusintraining · Oct 22, 2008

Please Lock Car

Purchase Leather Camel

Push Linear Cat

Programmable Logic Controller

Peace Love Carma <--- ran out... but K and C can sound alike

Play Live clipart

Piece Laughable Crock

TConnolly · Oct 22, 2008

"PLC" is a registered trademark of Allen Bradley.

PC refers to programmable controller, but PC is easily confused with personal computer, so lots of people call PCs PLCs, but technically PLC refers to only one brand of PC.

tomalbright · Oct 22, 2008

Alaric said:
"PLC" is a registered trademark of Allen Bradley.

PC refers to programmable controller, but PC is easily confused with personal computer, so lots of people call PCs PLCs, but technically PLC refers to only one brand of PC.

I've never heard this one in ::mumble mumble:: years. Most manufacturers call their systems "PLCs", you would think there would be a trademark infringement.

Are you sure?

TConnolly · Oct 22, 2008

Yes, I'm sure. Not only is PLC a registered trademark, "Programmable Logic Controller" is also a registered trademark.

AB puts the trademark designation on some of its literature. (Here is one example, see p9)

http://en.wikipedia.org/wiki/Odo_J._Struger#cite_note-what-5
http://www.sagitate.com/Product_AB.htm
http://www.machine-information-systems.com/PLC.html

However the PLC trademark has become the Kleenex of the automation world - it would be difficult to enforce the PLC trademark now and there would be very little to gain and lots of bad publicity.

Ken M · Oct 22, 2008

Hmmm...

the PLC trademark has become the Kleenex of the automation world

What are you suggesting? Some automation projects are just so exciting you need to keep a PLC handy ...?

RussB · Oct 22, 2008

Ken M said:
Hmmm... What are you suggesting? Some automation projects are just so exciting you need to keep a PLC handy ...?

I believe that this refers to the fact that the "PLC" is used to "kleen up" the "messes" left by mechanical engineers?

tomalbright · Oct 22, 2008

VERY interesting! I think it's odd that AB patented the name, yet Modicon was the first to produce a commercial PLC, and even called it that. I met Dick Morley years ago at a conference. He did say he was the "father" of PLCs.

Here's the wiki on PLCs, note the section "origin":

http://en.wikipedia.org/wiki/Programmable_logic_controller

TConnolly · Oct 22, 2008

While Morely is credited with inventing the programmable controller, its not at all certain that he at that time called it a PLC or programmable logic controller as opposed to just programmable controller.

Odo J Struger is credited with creating the PLC acronym.
http://en.wikipedia.org/wiki/Odo_J._Struger#cite_note-what-5

(FWIW: There are now more than enough links in this thread that the OP can answer his own question if he will just expend the effort to follow and read.)

bernie_carlton · Oct 22, 2008

Just to further terminate an expired equine - the trademark for 'PLC' by Allen Bradley is listed as 'DEAD' at the USPTO (United States Patent and Trademark Office).

http://tess2.uspto.gov/bin/jumpto?f=doc&state=58u3m5.2.138

Jim Dungar · Oct 22, 2008

Alaric said:
"PLC" is a registered trademark of Allen Bradley.

PC refers to programmable controller, but PC is easily confused with personal computer, so lots of people call PCs PLCs, but technically PLC refers to only one brand of PC.

Did you know that: "Rockwell™ is a trademark of The Monotype Corporation"

Having a name of a product (i.e. PLC-5) as a trademark is a method to prevent your product from being confused with a competitor's product, but it does not necessarily give you the right to its exclusive use. And if the registered trademark is not enforced (the way Coca-Cola does with Coke) it may become generic and open to use by any one (aspirin was once a register trademark).

So, yes it is true that at one time PLC meant a specific item, but technically now it is a generic term.

TConnolly · Oct 22, 2008

Jim Dungar said:
So, yes it is true that at one time PLC meant a specific item, but technically now it is a generic term.

Which is exactly what I meant when I called the PLC trademark the "Kleenex" of the automation industry.

Please understand that I'm not making a case for exclusiviity in the use of PLC, nothing of the sort, I'm only conveying a bit of history here about the evolution of the term PLC.

Dua Anjing · Oct 22, 2008

bernie_carlton said:
Just to further terminate an expired equine

mmmmmm

I would have thought (on our side of the puddle at least) that it would have been more of "encourage with malice" than terminate an expired equine.

Oh yeah and you left out Public Liability Company

bernie_carlton · Oct 22, 2008

I would have thought (on our side of the puddle at least) that it would have been more of "encourage with malice" than terminate an expired equine.

You are correct. 'Pummled Profusely' might have been appropriate also

plc

kalyan48

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rdrast

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geniusintraining

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TConnolly

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tomalbright

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Ken M

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tomalbright

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TConnolly

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bernie_carlton

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