[TenTec] Optical Encoder operation

[Mark Erbaugh]

Thanks for all the helpful replies, I think I have a better understanding
now.

Mark

----- Original Message -----
From: "holden" <holden@nac.net>
To: "Rich McCabe" <rich@1967z28.com>
Cc: <tentec@contesting.com>
Sent: Tuesday, August 13, 2002 17:38 PM
Subject: Re: [TenTec] Optical Encoder operation


> Most optical encoders actually have two (and often more) sensors in them,
so
> it only takes one encoder assembly to determine direction and position, or
> dial reading. The sensors, simplistically, are arranged in "quadrature" -
> consider one full cycle as being 180 degrees on or high (optical window
> open) and 180 degrees   low (optical window closed) . The two sensors are
> arranged so that one comes "on" 90 degrees, or one quarter cycle or pitch
> after the other. One sensor is for counting, the other for direction of
> count. Direction is determined by the state (level, or 0V - low, 5V -
high)
> of one channel when the other goes high (or low). If the direction of
> rotation of the optical wheel results in, for example, channel one going
> high when channel two is low, reversing the direction of rotation results
in
> channel one going high when channel two is high. The state of channel two
> when channel one goes high in this case  indicates the direction of
> rotation, or in the case of a freq dial, the frequency going up or down.
> Simple logic gating produces a steady "up" or "down" signal from the
> direction sensor depending on direction.
>
> Howie WB2AWQ
>
> Rich McCabe wrote:
>
> > Mark try this..
> >
> > http://www.cse.rmit.edu.au/design/mentoring/shaft_enc/lesson2.html
> >
> > ----- Original Message -----
> > From: "David McClafferty" <ve1adh@yahoo.ca>
> > To: "Mark Erbaugh" <mark@microenh.com>
> > Cc: "Tentec Reflector" <tentec@contesting.com>
> > Sent: Tuesday, August 13, 2002 3:56 PM
> > Subject: Re: [TenTec] Optical Encoder operation
> >
> > > Hi Mark, There are two sensors looking at the slots in
> > > the disc. The software looks at both and determines
> > > the direction by which one it sees first.
> > >
> > > 73, Dave, VE1ADH
> > >
> > > --- Mark Erbaugh <mark@microenh.com> wrote:
> > > > I believe I understand the basic operation of an
> > > > optical encoder, such as the 302. As you turn the
> > > > knob, a series of holes on a plate connected to the
> > > > shaft generate a series of pulses which the Pegasus
> > > > software counts and convert into a value indicating
> > > > movement.  My question is how does the Pegasus
> > > > determine which way (CW or CCW) the knob is being
> > > > turned?
> > > >
> > > > Mark
> > > >
> > > >
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