On 6/23/17 7:56 AM, Clark Sann wrote:
Mark
I suspect your cheap encoder is incompatible with the Blue. The BB Blue is designed to
operate with quadrature encoders. The Sparkfun site does not indicate your encoders are
quadrature. There's a lot of other gobblygook in their encoder specifications...magnets
and sensors etc...but sadly it's missing the word "quadrature".
Here is a link to a simple explaination of quadrature
encoders....https://www.dynapar.com/Technology/Encoder_Basics/Quadrature_Encoder/
Note that the quadrature encoder A and B outputs are 90 degrees out of phase.
This is critical. Without them being out of phase it is not possible to
determine what direction the shaft is being rotated.
So find a way to watch both encoder outputs while you slowly turn the encoder
in both directions. A dual channel oscilloscope or logic analyzer is best but
you might be able to do it with LEDs or two voltmeters. The A and B pulses
should never rise or fall at the same time. They need to be 90 degrees out of
phase with each other.
Get back to me if you have more questions.
Clark
Thanks Clark for the info. The encoder is a hall
effect sensor coupled with a disk that has a
series of magnets. It is quite low resolution but
does spin at motor speed which gives several
hundred pulses per second. I am using it mainly
for learning about motor control and I really
don't care about direction at least for now.
I did notice the ePEP hardware does support a
simple up (or down) count from the A input. If
this is the case I might be able to change the
Strawson library. I will post back one way or the
other
Mark
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