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

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-




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