Programming US Digital Encoder

[Thad House]

Originally Posted by TimTheGreat

So I am trying to get a motor to go to a certain position using the encoder provided by US Digital, and am having trouble.

self.talon = wpilib.CANTalon(15)
        self.talon.changeControlMode(CANTalon.ControlMode.Position)
        self.talon.setFeedbackDevice(CANTalon.FeedbackDevice.EncFalling) #Not sure if the encode is EncFalling or Quad
        self.talon.reverseSensor(True)
        self.talon.setP(1)
        self.talon.setPosition(0)

and in OperatorControl

  self.talon.set(270)

But when I enable the DS, the motor just keeps spinning, and the value goes past 270.

You do want to be using Quad for an encoder like that.

Remember that the encoder is always in 4x mode, which means that 1 rotation of the shaft is 1440 pulses is using a 360 CPR encoder. Moving from 0 to 270 is only moving the output shaft about 80 degrees. Is that what you want?

Also, the P gain needs to be a much smaller number then 1. With a P gain of one, your motor will always be moving at a full speed. I would recommend using a P gain of 0.01, if not 0.001 to start with, then start increasing from there if its not moving fast enough, or at all.