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Unread 15-05-2009, 14:26
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Jared Russell Jared Russell is offline
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FRC #0254 (The Cheesy Poofs), FRC #0341 (Miss Daisy)
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Re: Misbehaving encoders

Quote:
Originally Posted by nathanww View Post
"PWM" here is referring to the cable we've spliced to, not the output on the digital sidecar

I sketched out a diagram of eaxctly how it's set up and attached it.

We know the robot isn't reading the encoder because the value from Get() never changes, and the robot always reports that it is stopped, even when moving


Yep--we saw this, and when we checked it with a multimeter(we don't have an o-scope), we saw fluctuation in values--it just seems that the robot isn't interpreting it correctly.
That is a sweet MS Paint sketch

Everything looks correct to me. So the problem is either really obscure, or right under our noses.

More ideas:

1. Are you sure you are using the correct port on the cRIO for the sidecar? Are you sure the sidecar is fully powered (12V power from the main breaker is necessary)?

2. Try commenting out the encoder code and instead creating DigitalInputs on the same two DIO lines. Call Get() on that and turn the encoder to make sure that you can at least see the two lines fluctuating.

3. Since you have a multimeter, verify that you are getting (close to) 0V and 5V on the Ch A and Ch B outputs as you rotate the powered encoder.