Quadrature Errors, Old issue!

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Joined: Wed Nov 15, 2017 8:25 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
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Location: Springfield, MO. USA

Quadrature Errors, Old issue!

Post by Dave_C »

4 years ago I finished my Mill conversion to find that I had quadrature errors with my spindle encoder. I sent the encoder to Centroid, they tested it, said it was 100% OK and return it to me.

Ok, in the meantime I just changed the 324 and 325 parameters to "255" and forgot about it.

It never caused my any issues but last night I decided to dig into the issue and see if I could find the cause.

First step was to check the Automation Direct encoder cable to see if it was a shielded twisted pair and to my surprise, it was! (I was under the impression for some reason that it was not!)

So cable was good, proper type shield and good twisted pair. I immediately had a clue then as to what my issue had been all along!!! I had used a DB9 breakout connector with the snap over plastic shell. So being that the Acorn board is in the same cabinet as the VFD, I was getting "noise" from the drive by way of the plastic snap over shell of the DB9 connector.

So not having a good metal solder type DB9 on hand, I made an aluminum cover to fit tight around the plastic shell, grounded the aluminum shell cover to the DB9 and fastened it in place with some aluminum tape.

I then changed the 324 and 325 parameters back to the default of "3" and tested the mill spindle. No more quadrature errors.

So the lesson learned is don't use DB9 connectors, of any style or type, with plastic shells!

Had this given me any issues over the last 4 years I would have fixed it sooner. I suppose my errors were minor!

Dave C.
Grizzly G0678 Mill ,CNC conversion with Acorn. G4004G Lathe, Mach 3 conversion to Acorn.
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