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I love ladder logic and had been thinking about it!<BR>
<BR>
Ladder logic is functional programming (which will make Paul Davey happy!).<BR>
<BR>
Ladder logic has an obvious DHTML web interface for it (that said I am not volunteering to do that because I do Ajax web development for my job :) but given how common it is I would hope there is something free out there already. I personally am attempting to avoid requiring anything installed on a PC, that way web-phones can be used for development and for remote control, and also so there is no dependency on having either Windows or Linux installed.<BR>
<BR>
Charles, I am very keen to hear what you find out - especially if it is web based open-source (Python would be perfect, but PHP, Ruby, Lua, Perl or Linux CGI apps can all be hosted on the wifi router web server - probably even DOS apps in DOSBox).<BR>
<BR>
Simon - is that a volunteer I hear! ;)<BR>
<BR>
Cheers<BR>
<BR>
Morris.<BR>
<BR>
On Tue, 2009-06-30 at 10:22 +1200, Simon Knopp wrote:
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That project looks interesting. I agree, ladder logic is a good way to
get started with programming simple robots.
What would really make a tool such as that powerful would be the
ability to create functional blocks, either of ladder logic or code. A
block of ladder logic would allow higher level commands like in
Mindstorms---"turn 90º left" or "move forward for 1 second". A block
of code (much like PLCs' structured text) could allow one to write a
function in C (for example) and have it represented as a block within
the ladder logic environment. These blocks could be created by anyone
who knows the language and distributed easily to those that don't.
I know I'm sort of just describing what PLCs can already do, but to my
(relatively uninformed :-) mind it wouldn't be too difficult a feature
to implement into a system like that you linked to and would make more
powerful programming with ladder logic feasible and accessible to more
people.
Just my two cents worth.
Simon.
On 29/06/2009, at 9:55 PM, Charles Manning wrote:
> Morris and I had a very interesting conversation about simplifying
> robot programming.
>
> Many people are drawn to Mindstorms-like drag and drop programming.
> This is indeed a simple way to do very simple programming (but is
> hopeless for anything of reasonable complexity). These tools are also
> no open source or free.
>
> Fortuitously I got into a discussion with Timothy about PLC "ladder
> logic" programming. This could be a simple way to do very simple
> programs. There are a few very interesting open source ladder logic
> projects out there that compile a ladder and generate a "byte code"
> which runs on a tiny interpreter. These can be simple enough to run on
> a small AVR, moderate PIC, Linux box etc. Anything that can eat C.
>
> Ladder logic is a graphical representation of an electrical circuit
> that operates on inputs and outputs
> eg.
> | IN1 IN2 OUT1 |
> +-----[ ]---[ ]---( )------+
> | |
>
> If IN1 is on and IN2 is on then turn on output 1.
>
> Better descriptions in <A HREF="http://en.wikipedia.org/wiki/Ladder_logic">http://en.wikipedia.org/wiki/Ladder_logic</A>
>
> A ladder logic tool I'm going to look at more is at <A HREF="http://www.cq.cx/ladder.pl">http://www.cq.cx/ladder.pl</A>
>
> --Charles
>
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