Re: open-plc

[Bill Gatliff <bgat@billgatliff.com>]

Karl Hammar wrote:
>  Do anyone of you where the proper place to discuss open hardware is?
> I am going to start a project to replace plc's.
>   

I've gone down this route many times.  Never found the end, however.  :)

I would consider gEDA over kicad, it's more mature.  But a somewhat
steeper learning curve, perhaps.

The main challenge isn't going to be the hardware, it's going to be the
programming environment.  Lots of hardware can produce signals that look
like signals produced by PLCs, but those systems won't be as easy to
program as existing commercial PLCs without a pretty considerable
integration effort.

If you do your job right, you'd be able to realize your "plc" hardware
as a PC with a USB-connected GPIO device, at least for some definitions
of "plc".  And that would be a pretty interesting achievement in itself!

The MatPLC software is one place you might look for the software
pieces.  There are other examples, like EMC2, and so on.   Google is
your friend here, for sure!

This article is a little old, but might still be relevant:

http://www.linuxjournal.com/article/1339

A communications stack, among countless others:

http://www.ctiplcio.com/

The "beagleboard" would be a super-fast CPU, but with 1.8V i/o it would
need a daughtercard in order to make it useful.  Cogent's CSB740 uses
the same CPU, but has a little friendlier 3.3V i/o.  But neither comes
with any software stack to make it as programmable as a PLC.  Both
support Linux already, however.



Have fun!


b.g.

-- 
Bill Gatliff
bgat@billgatliff.com