A chemical process has a large number of measured variables
which are usually driven by fewer latent variables. The latent variables are extracted by using independent component analysis (ICA) and monitored to detect the fault.According to the situation of alarm limit violations of independent components
the diagnosis of faults is reduced to a string matching problem. The proposed method is data driven and any training data or a process model is not required. It was evaluated by the application to the Tennessee Eastman challenge process and its effectiveness was demonstrated.