"rangerssuck" wrote in message
...

A customer called last week with a problem on their packaging line. one of
the machines was running out of sync with the feed screw, and making a hell
of a mess of the labels.

I took a look and found that the (poorly documented, of course) machine had
an Allen-Bradley controller that was apparently misbehaving. After an hour
of warmup where it would work perfectly, even though the "Product Present"
prox sensor was inactive (and showed as such on the controller's LED
strip), it was still making "stick-a-label-on" output. This output went
through a time-delay relay to produce a pulse that triggered an air
solenoid that... well the details aren't really important.

Having ZERO information on the AB box or its programming, and having no
access to the programming cable or software, I took a different route. It
was pretty obvious what the thing had to do to work properly - it involved
looking at three inputs, going through a state table and generating a
timed pulse at the correct time.

I took a couple of quad OPTO-22 modules (one input,one output) and
literally electrical taped them together with an arduino board wired to the
I's and O's with pigtails hanging off to connect to the existing
controller. All told, didn't take much more than an hour to get the stuff
together.

I wired it in place, and the programming took about another hour to get the
timings correct. And VOILA! the machine is fixed.

So now I'm thinking that maybe there's a product to be made - a board that
holds a couple of Quad OPT-22 modules, a microcontroller, terminal blocks
and enough power supply to run from 24VDC or 120/240VAC. Programmable in
the language of your choice (mine is C, but whatever can run on an AVR).

As if I really need another project... I could bang this one out pretty
quick. And I KNOW I could use a few now and then - it would have been good
to have one sitting on the shelf ready to go last week.

Any thoughts?

Perhaps you could make an opto-22 board that an Arduino either plugs into,
like a large "Shield" or perhaps interfaces through a cable.

You could look up some of the micro PLC's that can be programmed by a keypad
and have a small LCD screen, I figure an Arduino board would need some
advantage over them to be competitive. Also it would be nice to have
Arduino's capabilities such as the interrupts to read encoders and high
precision timing of pulses in and out. With digital I/O, high speed
counters, pulse in, pulse out, digital communications, analog in, PWM out,
and so on, there would be a lot of potential.

RogerN