Talon SRX in PID Speed mode won't stop!

[mhaeberli]

Hi!

We have a Talon SRX (to a CIM motor, with a quadrature encoder) - it's attached via a pullup / breakout board to the encoder.
On our test robot board (no robot, just control system), it seems to behave as expected:

using control mode kSpeed - ...

(pseudo-code):

if (button1) {
talon.Set(1000.0); //turn it on.
}

if (button2) {
talon.Set(0.0); //turn it off.
}

- the talon starts and stops when commanded.

On our real bot, though, it won't stop once started.

(we also tried putting it in voltage mode; in that case

(pseudo-code):

if (button1) {
talon.Set(1.0); //turn it on.
}

if (button2) {
talon.Set(0.0); //turn it off.
}

Which works fine.

Stumped!

Martin Haeberli
(de-)mentor, FRC 3045 Gear Gremlins (formerly SWAT)