Fault Diagnosis of Relay Control Circuit Based on Discrete Event System

A new method based on discrete event system is proposed for fault diagnosis of a certain kind of circuit, such as a relay control circuit. The original algorithm to obtain a minimal test set is improved. By using the improved algorithm the finest testable partition can be obtained and the complex testability analysis is avoided. The basic model of the proposed method and the general rule for fault diagnosis are described in detail. At first, the relay control circuit is described with corresponding combinational logic circuit model. Then, the fault diagnosis model of the circuit-under-test is constructed based on the given DES model. This method is applied to diagnose a relay control circuit. The results indicate that this method can diagnose this kind of circuit effectively and the new algorithm has a much lower computational complexity than the original algorithm. The fault elements can be localized exactly and this method has high practical value.