On Friday 08 January 2021 11:06:00 Andreas Linnarsson wrote:

> It will increase by "1" after every (unsuccessful) completion of a fwd
> jog. After position 6 it will wrap around to 1, even though the index
> position isn't sensed. I understand if index isn't used after homing
> though.
>
> Do you know anyone who has used the carousel comp with this kind tool
> turret? Or am I the first? If they've made it work I'm quite curious
> about what their encoder wheel looked like or how they did it. I've
> 3D-printed a variety of designs in search for a pattern that the
> carousel comp would be compatible with but I cannot really get my head
> around if another design would be the solution. I haven't found
> anything that works so far and logically I can't see how it would work
> to stop on the first pocket trigger. Not since that will always be the
> same as the last one due to the reverse locking.
>
> Regards,
>
> Andreas

Can you describe your signal generation as it turns?

It seems to me that your next pulse s/b derived not from the carousel 
position, but from the locking pawl as it falls off a tooth and it then 
backs up against the new tooth it just fell off of to initiate the lock. 

And that the falling pawl generates a pulse to initiate the reversal 
itself. So you get one and only one edge pulse as it falls. And one 
might detect the locked rotor amps of the motor being stopped by the 
pawl to both turn off the motor, and tell linuxcnc that a lock in the 
new position has been achieved.

I would also if switching the motor with a relay, would use 2, wired so 
the when off, the motor armature is shorted, so the sequence would be, 
see the pawl fall, turn off the motor fwd relay so its back side 
contacts short the motor, stopping it fairly rapidly but gently, then 
enable the reverse relay maybe 100 milliseconds later. Lots easier on 
things too. Particularly the psu running the motor. There is also, for 
about 7 dollars US a BTS 7960 half bridge based board with 2 of those 
with a 27 volt rating that can switch 43 amps that does essentially the 
same thing as the relays and a bunch cheaper. I am controlling a 100 
watt 24 volt motor to drive a BS-1 indexing head from linuxcnc.  No 
heating even when my pid is miss set and its oscillating violently. I've 
a 450 watt 24 volt supply its crowbarred and turned off for a 3 minute 
cooldown, but no detectable heat from this board. Phenomenal little 2" 
square board for 7 bucks. Driving it both directions with a pwmgen in 
mode 2.

But I don't have such a tool changer critter myself, so I'm just 
guessing. My holdup is figuring out how to bold the spindle and drop a 
ratcheting impact tool onto the drawbar and run it, its an R8 spindle. 
And the end wrench supplied does not exert enough force to adequately 
hold the tool. So the ratcheting screwdriver is needed.

> Den fre 8 jan. 2021 kl 15:02 skrev andy pugh <bodge...@gmail.com>:
> > On Fri, 8 Jan 2021 at 13:27, Andreas Linnarsson
> >
> > <andreas.linnars...@gmail.com> wrote:
> > > Did I miss(do) anything?
> >
> > I don't think so.
> >
> > Can you look at the current-position HAL pin to see if it decreases
> > by 1 at the end of the reverse pulse?
> >
> > --
> > atp
> > "A motorcycle is a bicycle with a pandemonium attachment and is
> > designed for the especial use of mechanical geniuses, daredevils and
> > lunatics."
> > — George Fitch, Atlanta Constitution Newspaper, 1912
> >
> >
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Cheers, Gene Heskett
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 - Louis D. Brandeis
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