TalonSRX uses encoder when in Voltage mode

[while1fork]

We have been trying to read an encoder connected to a TalonSRX. We have it in voltage control mode, but are trying to read the velocity from the encoder.

However, we have come across some behavior that we can't understand. When we have an encoder plugged into the talon, even when the talon is in voltage control mode, it causes the talon to make the motor jitter and move slowly. The talon works fine if I remove the encoder (without changing the code).

Why is the encoder affecting how the talon works even when the code tells it not to use the encoder?

[GeeTwo]

A I understand things it shouldn't, if things are wired correctly.

If you don't get some more specific guidance from Omar or someone else at CTRE, check your encoder cables and breakouts to make sure everything is connected where it should be (including under a bit of flexing) and disconnected where it should not be connected (again, including under flexing). Also, check that you are using an encoder (not analog) breakout.

Also, double check your code to make sure you aren't giving the SRX conflicting signals. Perhaps you forgot to comment out something in your encoder code, and your remnant encoder code and your new constant voltage code are fighting each other.
If you don't find any issues, if you post your code here, or provide a link to your github or other code repository, there are several here on CD who will look your code over for this sort of thing.

Finally, if things still don't work, post the state of your SRX's diagnostic lights when it jitters; that may be illuminating.

[davidaustin]

Have you updated the firmware in your TalonSRX's? We saw some strange behavior until we remembered to do so.