I don't think it works this way.  It does not power down.   But it does
work exactly as per the specification.  There are 100 detented divisions
per revolution.  The A and B phase of course only change when there is
movement.

In theory you can get 400 steps per rev but the wheel has detents so there
is no good way to move it to a place between the marks.

This is OK because we get to define what "one revolution" means.  It one
rev is 0.01 inches them each mark is 0.0001 Will can define it to be inches
or metric.  The division are as fine or course as you like.   If you are
building a user interface with this wheel I think what's needed is a
selector that defines what one revolution means.   It will also need a
"zero" button and and axis selector

My plan is to place a small micro controller inside the pendent with the
wheel and an LCD screen and some other controls.  The uP will do the
translation.



On Thu, Feb 23, 2017 at 6:31 PM, Gene Heskett <ghesk...@shentel.net> wrote:

> But I think its something we may be able to outwit in the hal file.
>
> They appear to have a power save shutdown, and a power up lag.
>
> And seem to have timings independent from each other.  This is going to
> cause, unless we scale the encoder down by 4, one edge received occurs
> just as you start to turn it by hand, and again some milliseconds later
> after YOU have stopped turning the dial. When you stop moving it, it
> goes back to zero volts a few milliseconds later.
>
> This is looking at the A/B terminals, I have not yet checked the -A/-B
> terminals for their behavior.  It may be that this problem may disappear
> if differential receivers with lots of histerisys(sp?, when do we get a
> spell checker that knows these technical words?) would just ignore this.
>
> But be aware its there guys if you feed it straight into the encoder
> module as is. You have effectively only those positions at rest
> corresponding to A,B=0.  None of the other three combo's are available
> to you in the detent at rest condition. So you will move in a modulo4 at
> the start, and end of a move, always ending up in the 0/0 position when
> the wheel is at rest.
>
> I just checked the - terminals, it is not powering down, at rest they are
> both at the 5 volt rail. I was hopeing that we might have a true fine
> tune by using a straight edge went by=one motor microstep, but thats not
> going to happen, best we can do is one micro-step per detent felt.
>
> Now we know why such a precision looking and seemingly well built wheel
> was only a 20 dollar bill. ;-)  You can only use 1/4 of its real
> resolution.
>
> Now I need to find some cat5 intended for jumpers, eg stranded wire for
> use in the cable chain to the saddle. But the last jumper I bought was
> made from flat cable.  It works ok, but..., 8 wires isn't enough for
> everything either, I still need independent home switches, so thats 10.
> Sigh.  When does it end and you can switch to use it mode?
>
> I did measure how far I can move the crossfeed in w/o exposing the ball
> screw, 3.35". Thats enough to  put the tool tip on centerline, and work
> on something 6.7" in diameter w/o throwing swarf into the slot.  Said
> another way, stuff will need to be zeroed and an air cut made to check
> if its still covered at the smallest diameter of the job.  If not, move
> the toolpost mount, rezero, and cut some more air.
>
> Cheers, Gene Heskett
> --
> "There are four boxes to be used in defense of liberty:
>  soap, ballot, jury, and ammo. Please use in that order."
> -Ed Howdershelt (Author)
> Genes Web page <http://geneslinuxbox.net:6309/gene>
>
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-- 

Chris Albertson
Redondo Beach, California
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