MIB: CISCO-ENTITY-SENSOR-MIB.
The object name: entSensorStatus.
This variable indicates the present operational status of the sensor.
Possible values:
-  ok (1): means the agent can read the sensor value;
-  unavailable (2): means that the agent presently can not report the sensor value;
-  nonoperational (3) means that the agent believes the sensor is broken. The sensor could have a hard failure (e.g., disconnected wire), or a soft failure (e.g., out-of-range, jittery, or wildly fluctuating readings).