Re: open-plc
Bill Gatliff:
> 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.
I'll check that out, thanks.
> 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.
For the moment I'm most interested of the hardware part. It should look
like a plc, be rugged, and have exchangeable io-cards.
I think I'll rule out single board systems and stacked systems like
pc104. It should be easy to exchange io-cards, if possible hot-pluggable.
Software is another project, but for now I'll do it in c. And I don't
think I'll invest time to make it that plc-like. My main points is to
make better hw that my current programs could run on. And in that sense
it might be better to call it something else than open-plc.
> 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!
Yes, I've thought about that, but I don't want to have a mess of
usb-cables. I could use printed circuit usb lines, but spi looked more
suited for the job.
> 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.
I have looked at beagleboard, but it does not have ethernet.
> Have fun!
Yes I will!
> http://www.linuxjournal.com/article/4603
> http://en.wikipedia.org/wiki/IEC_61131
Thanks for all the links.
I'll put up some pages att http://aspodata.se/openhw/ when I have
something to show.
Regards,
/Karl
-----------------------------------------------------------------------
Karl Hammar Aspö Data karl@aspodata.se
Lilla Aspö 148 Networks
S-742 94 Östhammar +46 173 140 57 Computers
Sweden +46 70 511 97 84 Consulting
-----------------------------------------------------------------------
Reply to:
- References:
- open-plc
- From: karl@aspodata.se (Karl Hammar)
- Re: open-plc
- From: Bill Gatliff <bgat@billgatliff.com>