Re: [CAD_CAM_EDM_DRO] Help with encoder

caudlet wrote:

>I have Gecko 340's. I have 500 line rotary encoders on my servos.
>The color code of the encoder wires is Red, Black, Yel, Wht, Org, Blu
>and Brn. I put the motor on the bench and with a scope determined
>that (as expected) red is +5, blk is Gnd and that I had out of phase
>signals on the yel-blu set. The wht-org set are from what I can tell
>the differential outputs of the A and B (?) The other wire are INdex
>and signal grounds.
>
>Here is my problem. The machine runs but the math doesn't seem to
>work (almost like I am getting 1000 pps in quad rather than the 2000
>I would expect.) I am concerned that I have picked a differential
>pair as the AB set. Is there a standard color code? How could I
>setup with a dual trace scope to determine which leads are the REAL A
>& B signals. The 340 uses single ended inputs. How could I tell if
>the primary pair is supposed to be yel-wht or blu-org?
>
>

You should see a 90 degree phase shift between the A and B signals.
Using A and B\ is OK,
they have a 90 degree phase relationship, too. But, if you used A and
A\, then you would have
180 degree difference between them. The Gecko might actually seem to
work OK by counting
the edges, but it would most likely be making large errors in
positioning, as it would not
likely be getting good direction info this way. You should be able to
see the 90 degree phase
shift pretty easily. You might run the motor on a D cell to get a
constant speed.

So, if the yel-blu signals are 180 degrees out of phase, use yellow and
orange, for instance.

Jon