Thread: Can't read encoders
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Unread 05-02-2009, 16:38
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Re: Can't read encoders
Quote:
Originally Posted by intellec7 View Post
If it is relevant, I'm doing quadrature decoding and am using an NXT motor, which produces 720 quadrature transitions per rotation (180 rising pulses on a single channel per rotation).

I am using the latest cRIO image and LabVIEW edition.
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EDIT 2
This symptom only occurs when doing 4x decoding, and not 2x or 1x. I did read about something similar before, but I can't recall where.
LabView Update 3.0a and cRIO Version 11 corrected the problem of different rates being returned by the encoders.

You don't have a distance per count going into the open for the bottom encoder, I don't know what the default will be.

The values returned by the Encoder routines are not a function of the decode type (1X, 2X, or 4X). You should get 180 counts per revolution. Have you looked at the distance that is being returned? If you can go slow enough, you should be able to predict the distance based on revolutions.
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