Problem with AutoTune

Questions about using encoders with the Roboclaw product line
rohin
Posts: 1
Joined: Tue Sep 20, 2016 8:49 pm

Problem with AutoTune

Postby rohin » Tue Sep 20, 2016 8:58 pm

Hi!

I have the 2x7A Roboclaw controller. A couple of weeks back my controller was behaving fine with the Ion Motion app on Windows. But now when I use AutoTune for setting Velocity PID parameters, my motor does a couple of back flips slowly and then keeps on rotating for eternity. Also the Ion Motion app hangs up and I'm unable to stop the motor.

The PWM from the App works fine. The encoder value increases and decreases upon changing the PWM up and down. I am using the https://www.pololu.com/product/2827 Pololu Gearmotor.

I have rechecked my wiring and it does not seem to be creating the problem. Only the Green LED lights up and the Error LED stays off.

Please guide me what can I do.

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Basicmicro Support
Posts: 989
Joined: Thu Feb 26, 2015 9:45 pm

Re: Problem with AutoTune

Postby Basicmicro Support » Tue Sep 27, 2016 12:05 pm

1. Make sure the ecncoders are being read properly. Manual turn the motors while the IonMotion app is connected to the board and see if the particular motor encoder values change.
2. Use the PWM settings window to run the motors in the forward direction. The encoder values should increase when moving forward. Note that forward is when you slide the motor slider up.
3. If 1 or 2 has a problem check the encoder signal lines using an oscillascope. We have had problems with motors with the built in hall effect encoders from china. Their designs have a bad snubber circuit that allows large voltage spikes from the motors to get on the 5v and signal lines of the encoders. If this is the case you can get false encoder pulses. It is possible that the encoders could even be damaged by it.


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