The Self-Diagnose Algorithm for Liquid Level Sensor on WSN Node

In order to diagnose the state of the liquid level sensor on the tank truck and make sure the wireless sensor networks (WSN) work properly, this paper studies an on-line self fault diagnosing method for liquid level sensors installed on oil tank trucks. First, a flexible fault sensing circuit is designed as a state detection module on sensor node. Second, a self-diagnosing algorithm is proposed, the Mean-Variance model is used to analysis the measuring values and the liquid density is taken as the relationship of sensors. At last, the state detection module compares the statistics characteristic quantities with threshold values to get the condition attributes and detects the failure of the liquid level sensor. Field experiments and simulations at the detection accuracy and the misdiagnosis probability show that this self-diagnosing algorithm is suit to the liquid level sensor on the oil tank trucks.