Let me introduce myself, I am responsible of engineering department at Embedded Automation (www.embeddedautomation.com). I believe that LinuxPLC control engine should be based on the modern programming methods to differentiate it self from the traditional ladder logic PLCs. As you all know that it is extremely hard to find new programmers who want to program in ladder logic, if you find one they want to be paid lot higher. The success of this project is in the hands new generation of engineers and
programmers, it has to be very attractive for the new generation of control engineers. The old PLC programmer user will not use the LinuxPLC, so why
bother introducing it with ladder logic.

I propose that the low level of the Control Engine should be written in C and the application layer should support C, Java and flowcharting languages. Having a common library for PID loops, alarms, timers, etc will help.

I am setting up a test bench with our EA2000 running SST DeviceNet talking to Wago I/Os. EA2000 is an embedded logic controller based on Intel Pentium with local and sensor bus I/Os, go to our web sight for more detail. Sooner any one have the code available, fire it my way and we will test it out.


JB Golee - Surrey, BC, Canada 604-543-9701
[email protected]



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On Tue, Jan 11, 2000 at 07:28:41PM -0800, JB Golee wrote:
> I propose that the low level of the Control Engine should be written in C
> and the application layer should support C, Java and flowcharting
> languages.

I agree, with the proviso that stepladder should also be supported.

It's not that hard.


Jiri
--
Jiri Baum <[email protected]>
On the Internet, nobody knows if you are a @{[@{[open(0),<0>]}-1]}-line
perl script...

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JB Golee wrote:
>
> ..." As you all
> know that it is extremely hard to find new programmers who want to program
> in ladder logic, if you find one they want to be paid lot higher.

Programmers are a one-time expense, and if you want to run your plant on code written by the lowest bidder who probably has no industry
experience go ahead. Just don't do it down here in the oil-patch, these plants are dangerous!

Continued maintenance support is more important. Try finding electrical maintenance personnel who can work in C, or java. One reason for the
success of ladder is how easy it is for the plant electrical types to work with.

PLC stuff must be used and maintained 24hours/day 366 days/year. While electricians know they'll be working Saturday night, programmers seem to
think they can pick and choose their own hours.

If the LinuxPLC project is to succeed in industry it needs to speak ladder logic. Ladder doesn't have to be the only way to program it, but
it must be one way.

Or ... rename this thing and try to compete against the Honeywell and Foxboro TDC stuff.

Mark

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If we're serious about coming up with something we can call a PLC, then it should be able to do what a PLC does, and that means it should be
programmable in standard PLC languages: IEC 61131-3. Adding other languages like C or whatever you like would be fine, but the IEC 61131-3 languages
should be the minimum.

As far as what differentiates a PLC from any other controller, think back to the invention of the PLC. It was a computer all along. The name
"programmable logic controller" was chosen, as I recall, to keep it out of the hands of those who controlled the purchase of computers. If you wanted a computer for the plant floor you had to find a way to get past the computer committee (later MIS dept.). What distinguished the early PLCs from regular computers was their scanning architecture. They weren't interrupt-driven
back then, and most still are not.

Pete Cleaveland
I&CS

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This all depends on where you recruit your new PLC programmers from.

In the Uk, for example, PLC programers are traditionally recruited from the
ranks of Electrical Engineers, occasionally they are Mechanical or Process
Engineers, increasingly they are Mechatronics Engineers.

Every engineer I know who comes into the dicipline from the IT end and who
started programming in C, took to ladder logic like a duck to water.
Further, once they'd had ladder they didn't want it the other way.

Incidently, computer programmers (C, C++, Java PC based applications) are
generally higher paid in the UK than PLC programmers.

-----Original Message-----
From: [email protected] On
Behalf Of JB Golee
To: LinuxPLC
Subject: LinuxPLC: LinuxPLC control engine
Let me introduce my self, I am responsible of engineering department at
Embedded Automation (www.embeddedautomation.com). I believe that LinuxPLC
control engine should be based on the modern programming methods to
differentiate it self from the traditional ladder logic PLCs. As you all
know that it is extremely hard to find new programmers who want to program
in ladder logic, if you find one they want to be paid lot higher. The
success of this project is in the hands new generation of engineers and
programmers, it has to be very attractive for the new generation of control
engineers. The old PLC programmer user will not use the LinuxPLC, so why
bother introducing it with ladder logic.

I propose that the low level of the Control Engine should be written in C
and the application layer should support C, Java and flowcharting languages.
Having a common library for PID loops, alarms, timers, etc will help.

I am setting up a test bench with our EA2000 running SST DeviceNet talking
to Wago I/Os. EA2000 is an embedded logic controller based on Intel Pentium
with local and sensor bus I/Os, go to our web sight for more detail. Sooner
any one have the code available, fire it my way and we will test it out.

JB Golee - Surrey, BC, Canada 604-543-9701
[email protected]

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On Wed Jan 12 11:45:09 2000 Mark Hutton wrote...
>
>This all depends on where you recruit your new PLC programmers from.
>
>In the Uk, for example, PLC programers are traditionally recruited from the
>ranks of Electrical Engineers, occasionally they are Mechanical or Process
>Engineers, increasingly they are Mechatronics Engineers.
>
>Every engineer I know who comes into the dicipline from the IT end and who
>started programming in C, took to ladder logic like a duck to water.
>Further, once they'd had ladder they didn't want it the other way.
>
>Incidently, computer programmers (C, C++, Java PC based applications) are
>generally higher paid in the UK than PLC programmers.
>

It's not any different in the states.

--
Stan Brown [email protected] 843-745-3154
Westvaco
Charleston SC.

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I agree wholeheartedly with this as an industrial electrician. 98% of maintaining and modifying these programs are done by we electricians. I'm the only one of 20 of us who know ANY C, or C++, and I'm no hotshot. We strongly lobby against any PLC systems that don't use ladder logic.


--- Mark Bayern <[email protected]> wrote:
> JB Golee wrote:
> >
> > ..." As you all
> > know that it is extremely hard to find new programmers who want to program
> > in ladder logic, if you find one they want to be paid lot higher.
>
> Programmers are a one-time expense, and if you want to run your plant on
> code written by the lowest bidder who probably has no industry
> experience go ahead. Just don't do it down here in the oil-patch, these
> plants are dangerous!
>
> Continued maintenance support is more important. Try finding electrical
> maintenance personnel who can work in C, or java. One reason for the
> success of ladder is how easy it is for the plant electrical types to
> work with.
>
> PLC stuff must be used and maintained 24hours/day 366 days/year. While
> electricians know they'll be working Saturday night, programmers seem to
> think they can pick and choose their own hours.
>
> If the LinuxPLC project is to succeed in industry it needs to speak
> ladder logic. Ladder doesn't have to be the only way to program it, but
> it must be one way.
>
> Or ... rename this thing and try to compete against the Honeywell and
> Foxboro TDC stuff.

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