sensors

Description

An array of sensor objects that make up the fan enclosure object. The sensors are what's monitored to determine the functional state of the fan.

A sensor's functional range is determined by the following equation(where [target] is current requested target of the fan):

• Minimum = ([target] _ (100 - deviation) / 100) _ factor + offset
• Maximum = ([target] _ (100 + deviation) / 100) _ factor + offset

Therefore, a fan sensor must be above the minimum and less than the maximum to be deemed functional.

Attribute Value(s)

• name - string
  • The name of the fan tach sensors located under the /xyz/openbmc_project/sensors/fan_tach D-Bus path.
• has_target - boolean
  • Whether this sensor D-Bus object contains the Target property or not.
• target_interface - string (Optional)
  • The D-Bus interface containing the Target property. This defaults to xyz.openbmc_project.Control.FanSpeed for RPM controlled fans or can be set to xyz.openbmc_project.Control.FanPwm for PWM controlled fans.
• target_path - string (Optional)
  • The D-Bus full object path containing the Target property. This defaults to /xyz/openbmc_project/sensors/fan_tach+name.
• factor - double (Optional)
  • A value to multiply the current target by to adjust the monitoring of this sensor due to how the hardware works. This sensor attribute is optional and defaults to 1.0.
• offset - integer (Optional)
  • A value to shift the current target by to adjust the monitoring of this sensor due to how the hardware works. This sensors attribute is optional and defaults to 0.

Example

{
  "fans": [
    {
      "inventory": "/system/chassis/motherboard/fan0",
      "allowed_out_of_range_time": 30,
      "functional_delay": 5,
      "deviation": 15,
      "num_sensors_nonfunc_for_fan_nonfunc": 1,
      "monitor_start_delay": 30,
      "fan_missing_error_delay": 20,
      "nonfunc_rotor_error_delay": 0,
      "sensors": [
        {
          "name": "fan0_0",
          "has_target": true,
          "target_interface": "xyz.openbmc_project.Control.FanPwm",
          "target_path": "/xyz/openbmc_project/control/fanpwm/PWM0"
        },
        {
          "name": "fan0_1",
          "has_target": false,
          "factor": 1.45,
          "offset": -909
        }
      ]
    }
  ]
}