What happens when an encoder goes out?

[Inconceivable]

Thanks a lot! It's good to know that. Now that I've thought a bit about it, it would probably be equal effective to give the driver the ability to switch modes. The driver can recognize an out of control wheel just as well as a [well written] program. He would probably react slower, but having the driver do it would ensure that the robot wouldn't go into V-mode at an undesired time, and the driver may want to go into V-mode for some reason. In fact, some drivers prefer the V-mode for everything except fine control, which is where speed mode really comes in handy. Just for safety though, it would probably be good to have an auto-switch feature: if an encoder is stationary for more than one second while more than, say, 2 volts are being applied to the motor, switch modes! I've heard, however, that the serial port on the cRIO has a little trouble both setting values and reading RPM from the jags simultaneously...