Re: [Spam] RE: [CAD_CAM_EDM_DRO] Quadrature encoders

Hi Andrey,

It might be that TurboCNC is looking for EVERY edge of the two phases. Someone
commented below that some encoders send one cycle per detent, but fast.

My decoding only looks for a single edge in either direction, only one count per
cycle.

Do you have the lines pulled up to +5V (parallel port pins)? Caps might help.

Perhaps Jerry or Tony could comment.

Alan KM6VV

Andrey Lipavsky wrote:

> I was able to get only the Bourns 24-detent/24-pulse unit, as it's the only
> one Bourns actively manufactures. However, I'm seeing some strange behavior
> with TurboCNC. There doesn't seem to be a consistent detent count that
> correlates to step increments. For example, I turn the dial 3 ticks and get
> one increment of motion, then I turn 4 ticks and get 4 increments of motion,
> then I turn 5 ticks and get one increment of motion. Also, on occasion and
> while turning in the same direction, I will get a reverse increment in the
> midst of correctly-directed ones.
>
> The Bourns data sheet recommends a 0.0015uf cap across the A&B inputs to
> deal with debounce. Could this have something to do with it or am I simply
> dealing with a limitation of a mechanical encoder?
>
> Any insight and wisdom would be much appreciated.
>
> Andrey
>
> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of CalBoy101
> Sent: Thursday, June 16, 2005 2:43 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: Re: [Spam] RE: [CAD_CAM_EDM_DRO] Quadrature encoders
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Alan Marconett"
> <KM6VV@a...> wrote:
>
>>Hi Andrey,
>>
>>I like the HP shaft encoders $$$. US Digital has encoders as
>
> well. You
>
>>might look at Bourns, DigiKey has them, ECW1J-B24-BC0024. I have
>
> a pair,
>
>>haven't implemented them yet. A little more detent then I'd like,
>
> but you
>
>>might like it. About $3 ea.
>>
>>Alan KM6VV
>
>
> Andrey-
>
> Depending on what you're hooking them up to, you may want the Bourns
> encoders that genenerate 6 "cycles" per revolution, the part number
> above generates 24 and also has 24 mechanical detents. When you hook
> up the encoders above to the Mach package for example using the
> Keygrabber tool, you'll get 4 increments per mechanical detent, not
> what you want. The 6 cycle ones will give you one increment per
> detent. They make one with 24 detents and 6 cycles.
>
> The reason this happens is most interfaces generate an increment at
> every edge coming out of the encoder, and their are 4 edges per
> cycle.
>
> Good luck-
>