On Thu, 2008-11-27 at 11:09 -0500, Gene Heskett wrote:
... snip
> Somewhere in that controller there should be the equ of a turn left or turn 
> right switch.  That is where I'd hit it with a pair of reed relays driven by 
> the pc.  The older version had them obvious, right in the dial you turned.

I'll take a look.

> If it can make a full turn in 20 seconds, that's about 10x faster than mine, 
> which is the old drive two motors design.  The image would go flying by so 
> fast there would be lag blur in most of the ccd sensors.

I'm pretty sure mine are the same as yours. I just needed a number to
indicate that the length of time of the rotate command could be a valid
means of setting an adequate position. My weather-cam setup takes a
snapshot at Home, then rotates and stops at position two, takes a
snapshot, rotates, etc. Finally, it does a longer than needed return, to
reset Home.

> Emc could I'm sure count the power pulses going out to the top motor, using a 
> neon lamp and a photo transistor, you would have either 120 or 100 pulses per 
> second to count depending on where you lived and its power standard.  To use, 
> put the neon lamp across the primary & keep track of which direction in emc.  
> Don't forget the series r for the lamp though.

This is why I go off topic occasionally, I get replies with all these
good ideas. Thanks.

> Or another idea, use optocouplers, one across each motor winding and emc can 
> decode those just as if it were following any quadrature encoded signal 
> because there will be a timing difference in the two optocouplers outputs 
> depending on which direction the motor is being driven.  I rather like that 
> and it only takes 5 wires including ground to do.  That hal component may 
> already be part of the recent emc package.

I'd also like to use HAL to control a generator, but I need a setup that
would boot within a minute of a power outage, start the generator,
control and monitor; the generator, mains, controller and starting
battery recharge and transfer switch. I suppose if I worked at it I
could get Ubuntu/EMC2 to boot quicker, though if I actually timed it, it
might be close already. Also, I guess realtime is only needed for the
governor, which I already have a mechanical version. There's more
thinking to be done.

Happy Thanksgiving to everyone.
----------
Kirk
http://www.wallacecompany.com/machine_shop/



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