[FTC]: Tips for Teams going to the Vex Championships

[gblake]

Originally Posted by Lowfategg

Sorry to say it is. The battery can only supply so much when discharged and the controller does not know this. Once the motors draw to much and pull the voltage down under something like 6 volts the controller dies and leaves the robot in a loop of rebooting. Thats why charged batteries are key to fixing this problem.

I have seen this to much at competitions. You can tell when this happens by looking at the lights on the side of the controller. If power blinks on and off like some one is turning the power on and off then the controller has crashed. This happens since once the controller crashes it restarts (since the voltage goes back up) but once it turns on it see RC and boots back into auto mode which then crashes the controller again since it tries to draw power again.

Precision is important when using English. Let me see if I can untangle the causes and effects being discussed here.

4 Amps is max current the Vex microcontroller will supply through the sum of all of its PWM/Motor ports.

Attempting to draw more than 4 Amps through the PWM/Motor does not cause a Vex microcontroller to reset.

Drawing current out of the Vex batteries will result in a voltage drop at the battery's output terminals.

If the current drawn is enough to lower the Vex battery's voltage far enough below 5 Volts, the Vex microcontroller will shutdown and be reset when it starts back up.

Sometimes this happens during matches when the loads the motors are experiencing rise and then fall and when the robot's battery isn't up to the task of keeping the robot healthy. The current drawn rises and falls. The battery voltage falls and then rises. The microcontroller shuts down when the voltage drops, and restarts when the voltage rises. At start-up the microcontroller starts executing it's user code, beginning with the first instruction of that code.

Blake