Re: [CAD_CAM_EDM_DRO] Encoder wiring question.

wayne_j_hill@... wrote:

> Hello All,
>
> (I have searched the FAQ area before asking this question.)
>
> I am turning the path from steppers to DC servos. Right now I am
> experimenting with simple testing. I have purchased a GeckoDrive 340
> and a used DC motor (2.5" dia X 5.0" w/.375 shaft) with an encoder
> attached. My question is the encoder did not have pinout
> information. There are 10 pins on it. I have determined the +5VDC
> and ground pins from the IC's on the circuit. How do I find the
> Phase A and Phase B pins and the Quad resolution of the encoder?
> Have not applied power to anything yet.

If you already know +5 and Gnd, that's the hard part. Use a DVM,
or even an LED and resistor to figure out the A and B outputs.
The A and B outputs will change from hi to lo and back very quickly
with small movements of the motor shaft. If it also has an index
channel, that will only have a change one way or the other over
a very small part of the rotation, about equal to one quadrature
cycle. (There are some 10 wire encoders like the QEDS-7163 that
I have a few of that also have linear outputs for the A and B as well
as the standard TTL signals, and no index.)

Since you have the Gecko drives, you can use a computer and
CNC control program to measure the encoder counts/rev.
What you do is mark the shaft, and then command a slow movement
(to be sure you don't lose sync) and vary the amount you move
until you get exactly one rotation. (You can verify you have it
exactly by then commanding a move of 10 x that far and making sure
you still come back the the same spot.) You can set an arbitrary
calibration like 1" = 1000 steps to start with. Most encoders will
give common counts like 500, 512, 1000, 1024, 2000, 2048, 4000
or 4096 counts/rev. So, you can pretty quickly narrow in on the
most likely values.

Jon