description: >

    Implement to provide hard shutdown class sensor thresholds.  Objects
    implementing Sensor.Threshold.HardShutdown must be instantiated in the
    correct hierarchy within the sensors namespace.  The following sensor
    hierarchies are recognized:
      airflow
      altitude
      current
      energy
      fan_tach
      power
      pressure
      temperature
      utilization
      voltage

    Additionally, any object implementing Sensor.Threshold.HardShutdown must
    also implement Sensor.Value.

properties:
    - name: HardShutdownHigh
      type: double
      default: NaN
      description: >
          The upper bound of the shutdown threshold.  A value of 'NaN' is used
          to indicate there is no threshold of this type.
    - name: HardShutdownLow
      type: double
      default: NaN
      description: >
          The lower bound of the shutdown threshold.  A value of 'NaN' is used
          to indicate there is no threshold of this type.
    - name: HardShutdownAlarmHigh
      type: boolean
      description: >
          True if the sensor value has exceeded the defined bound.
          False if the sensor value has not exceeded the defined bound.

          HardShutdownAlarmHigh may be set to False to clear an alarm condition.
          The behavior of setting HardShutdownAlarmHigh to True is undefined.
    - name: HardShutdownAlarmLow
      type: boolean
      description: >
          True if the sensor value has exceeded the defined bound.
          False if the sensor value has not exceeded the defined bound.

          HardShutdownAlarmLow may be set to False to clear an alarm condition.
          The behavior of setting HardShutdownAlarmLow to True is undefined.

signals:
    - name: HardShutdownHighAlarmAsserted
      description: >
          The high threshold alarm asserted.
      properties:
         - name: SensorValue
           type: double
           description: >
               The sensor value that triggered the alarm change.
    - name: HardShutdownHighAlarmDeasserted
      description: >
          The high threshold alarm deasserted.
      properties:
         - name: SensorValue
           type: double
           description: >
               The sensor value that triggered the alarm change.
    - name: HardShutdownLowAlarmAsserted
      description: >
          The low threshold alarm asserted.
      properties:
         - name: SensorValue
           type: double
           description: >
               The sensor value that triggered the alarm change.
    - name: HardShutdownLowAlarmDeasserted
      description: >
          The low threshold alarm deasserted.
      properties:
         - name: SensorValue
           type: double
           description: >
               The sensor value that triggered the alarm change.