Platform first, then controller

R

Thread Starter

Robert Oglesby

Thanks to Phil Covington and M. Robert Martin for the kind words on our
products. Having worked with us and our products, I think you know that our
involvement here is an effort to continue to give you guys what you want,
instead of what we want you to have ;-)

I am a bit surprised that nobody really attacked or supported my first post.
But I think the content was important enough that I want to stir the nest a
bit. To anyone that has been monitoring the list for even a day ot two, it
is obvious that there are virtually limitless opinions about what a PLC is
and isn't, about what control languages are good and bad, about how data
should be structured, etc, etc. You have more effectively proven my position
than I could have hoped to.

The reason that people like Linux in the first place, is that they have
choices. Ditto for virtually every standard OS/Platform out there. This
effort will only succeed if a standard platform is defined, exclusive of a
control engine, and then multiple options for the control itself are
presented. Arguments like "it'll only be a real PLC if..." or "ladder must
be implemented this way..." or "it should...or shouldn't...be a PLC..." are
the very reason that we don't have any form of standardization today.

At its foundation, every control product is simply IOBC - Ins, Outs, Brains,
and Comm. So any plaform that establishes a standard way of implementing
those basic requirements is a control platform. Whether it runs ladder and
and we call it a PLC, or flow charts on a PC, or SCADA on a workstation,
it's all just IOBC. The only real difference between control system A and B
is topology, latency, and performance. The requirements of process are
different than motion are different than machine control - but - at some
fundamental level, they are all just IOBC. If you define a platform that
provides standards based access to the IO and C, while allowing standards
based access to a user selectable B, you have the foundation of a truly
standard platform. Anything short of a user selectable control engine
running on fully standard fully scalable hardware, is a nice hobby or at
best a niche product...

Anybody?

Bob Oglesby
Host Engineering, Inc.
www.hosteng.com

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K
On Thu, Jan 13, 2000 at 11:28:23AM -0500, Robert Oglesby wrote:
...
> At its foundation, every control product is simply IOBC - Ins, Outs, Brains,
> and Comm. So any plaform that establishes a standard way of implementing
> those basic requirements is a control platform. Whether it runs ladder and
> and we call it a PLC, or flow charts on a PC, or SCADA on a workstation,
> it's all just IOBC. The only real difference between control system A and B

Good, concise description! Maybe that can be reworked into a usable
acronym, if the order isn't too critical... CIBO, perhaps? :)

> is topology, latency, and performance. The requirements of process are
> different than motion are different than machine control - but - at some
> fundamental level, they are all just IOBC. If you define a platform that
> provides standards based access to the IO and C, while allowing standards
> based access to a user selectable B, you have the foundation of a truly
> standard platform. Anything short of a user selectable control engine
> running on fully standard fully scalable hardware, is a nice hobby or at
> best a niche product...

Not that there's anything wrong with that, as a pragmatic starting
point, and perhaps something that an individual can prototype and
get working. But I think you've hit the nail on the head.

--
Ken Irving
Trident Software
[email protected]
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