Fault-Tolerant Encoder and its Application for Elevators

摘要

Fault-tolerant systems must be able to detect, diagnose, compensate and recover from faults. They are used in safety critical applications and in systems where high availability is required. The paper describes a fault-tolerant encoder and the related fault diagnosis. The encoder provides speed and direction information and is fault-tolerant for one sensor failure. The paper will mention two possible applications in elevators. The first one is speed and direction monitoring during rescue operation (see EN81-1:1998/A2:2004(E) 6.6.2 and 14.2.1.4), where high availability is desired. The second application is an electronic overspeed governor (safety critical application), according to EN81-1/2:1998/A1:2005 and IEC 61508.