These settings are automatically filled out when you press the Autotune button.
Under normal circumstances, they should not need to be changed.
Enable Runaway Detection
The control system does its best to detect runaway channels, and stops when it detects them. This can occur if the feedback input is disconnected or is connected backwards, or if the motor leads are plugged in the wrong way around.
If your system jams up or is not powerful enough to maintain control, the control system may mistake that for disconnected feedback and stop. To get out of the Control Error state in serial mode, reissue a Start command. In analog and RC, jiggle the controls back and forth a few times.
Runaway Time
The amount of time to wait on a stuck system before assuming control has been lost.