Abstract: Based on analyzing the Influence coming from pulse-type faults of inputs, two series of detection and identification algorithms, including off-line and on-line detection, are built. In order to build the on-line detection approaches, and deal with step-type faults, a simple transformation is suggested. Using this transformation, we can use all kinds of diagnosis methods to detect and identify step-type faults. At the end of this paper, a simulation is done to show that the on-line detection and identification algorithms are efficient and practical.