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Prop PLC software needed..( maybe an idea for the Propeller contest) — Parallax Forums

Prop PLC software needed..( maybe an idea for the Propeller contest)

OzStampOzStamp Posts: 377
edited 2008-01-24 03:34 in Propeller 1
Dear Fellow Proppers.
I have seen over the years several postings from people
that refer to the fact that a Basic Stamp or now the Propeller would be
a good PLC replacement.
I have attached a very simple code example pasted from the Mitsubishi GXWin software.
This program is a simple logic relay ladder program.
Showing 8 inputs ( some N.O contact and some N.C closed contacts.) and also 1 output
marked as Y0 ( notice feedback from YO) like a selfhold contact..
Just wandering if anybody has had a go at writing a decent program that
would make it easy to enter this sort of logic ( this is entry level stupid simple stuff for a PLC)
and needs be able to do much more complex stuff as well.
The PLC that this program as attached is targetted for has awesome capability.
It can scan 1000's of inputs scan time sub mSec.. adding a 1000 lines of code does not
really alter the total scan time.
the non expandable version of this PLC costs less than $400.00 here (AU DOLLARS)

For Parallax to be successfull in that mass.. small PLC market somebody needs to
write a decent compiler with a GUI interface .( Prize money contest .. good timing)
So that the people that use these PLC's can use the propeller... with an easy to use interface.
You want a list of features needed.. the list is long.
Floating Point math needed
High speed pulse output ( ramping/ acc dacc·· positioning on 2-3 axis)
be able to handle encoder feedback (100KHZ plus on a/b phase encoders 2-3channels)
be able to look at rising/falling edges· .. do 1 scan operations only..
adding .. multiplying..( 32bits ) compare statements galore..
setting and resetting of hundreds of internal flags.. shift registers ..bit access needed.

etc etc etc .. some of the small PLC's have 100's of software functions are are wicked fast..
There have been a few implimentations of PLC code generators by various companies
and some are not bad .. but they really all lack the serious grunt the larger mainstream manufacturers
offer even in their entry level PLC...
Is there anybody out there that is looking at doing something in this area. ?
Cheers· Ron Mel OZ

Comments

  • Bryan K.Bryan K. Posts: 47
    edited 2008-01-24 03:34
    I had a few passing thoughts in the matter. I am currently co-op-ing at a control systems company now (co-op through a college course cirriculum) the company uses an AMD processor running Windows CE. I had a few thoughts of either using the prop or the BASIC STAMP and communicating via either ethernet or a high speed serial link (propbably a multidrop connection to multiple props) using the free STAMP Plot software, or the PLX-DAQ provided on Parallax's site. At work, we use ethernet to connect all the processors, so the limit of how many are on a single line is the bandwidth and the IP address. I dont want to get this involved, but I am also looking into making the Prop chip into a descent home automation controller (live control or automated, freeze outputs if communication lost, things like that..) I dont think, or wold recommend running an OS for a couple of I/O pins, but a plant site is another story....
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