Package edu.wpi.first.wpilibj

Class MotorSafety

java.lang.Object
edu.wpi.first.wpilibj.MotorSafety
Direct Known Subclasses:
NidecBrushless, PWMMotorController, Relay, RobotDriveBase
public abstract class MotorSafety
extends Object
The Motor Safety feature acts as a watchdog timer for an individual motor. It operates by maintaining a timer that tracks how long it has been since the feed() method has been called for that actuator. Code in the Driver Station class initiates a comparison of these timers to the timeout values for any actuator with safety enabled every 5 received packets (100ms nominal).

The subclass should call feed() whenever the motor value is updated.

  • Constructor Summary

    Constructors 
    Constructor Description
    MotorSafety()
    MotorSafety constructor.

  • Method Summary

    Modifier and Type Method Description
    void check()
    Check if this motor has exceeded its timeout.
    static void checkMotors()
    Check the motors to see if any have timed out.
    void feed()
    Feed the motor safety object.
    abstract String getDescription()
    Returns a description to print when an error occurs.
    double getExpiration()
    Retrieve the timeout value for the corresponding motor safety object.
    boolean isAlive()
    Determine of the motor is still operating or has timed out.
    boolean isSafetyEnabled()
    Return the state of the motor safety enabled flag.
    void setExpiration​(double expirationTime)
    Set the expiration time for the corresponding motor safety object.
    void setSafetyEnabled​(boolean enabled)
    Enable/disable motor safety for this device.
    abstract void stopMotor()
    Called to stop the motor when the timeout expires.

    Methods inherited from class java.lang.Object

    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

  • Constructor Details

  • Method Details

    • feed

      public void feed()
      Feed the motor safety object.

      Resets the timer on this object that is used to do the timeouts.

    • setExpiration

      public void setExpiration​(double expirationTime)
      Set the expiration time for the corresponding motor safety object.
      Parameters:
      expirationTime - The timeout value in seconds.

    • getExpiration

      public double getExpiration()
      Retrieve the timeout value for the corresponding motor safety object.
      Returns:
      the timeout value in seconds.

    • isAlive

      public boolean isAlive()
      Determine of the motor is still operating or has timed out.
      Returns:
      a true value if the motor is still operating normally and hasn't timed out.

    • check

      public void check()
      Check if this motor has exceeded its timeout. This method is called periodically to determine if this motor has exceeded its timeout value. If it has, the stop method is called, and the motor is shut down until its value is updated again.

    • setSafetyEnabled

      public void setSafetyEnabled​(boolean enabled)
      Enable/disable motor safety for this device.

      Turn on and off the motor safety option for this PWM object.

      Parameters:
      enabled - True if motor safety is enforced for this object

    • isSafetyEnabled

      public boolean isSafetyEnabled()
      Return the state of the motor safety enabled flag.

      Return if the motor safety is currently enabled for this device.

      Returns:
      True if motor safety is enforced for this device

    • checkMotors

      public static void checkMotors()
      Check the motors to see if any have timed out.

      This static method is called periodically to poll all the motors and stop any that have timed out.

    • stopMotor

      public abstract void stopMotor()
      Called to stop the motor when the timeout expires.

    • getDescription

      public abstract String getDescription()
      Returns a description to print when an error occurs.
      Returns:
      Description to print when an error occurs.