The data should capture the typical normal and abnormal behavior of the process variable under consideration during the normal and abnormal operations of the process;• For mulit mode processes, the data should be collected for all the possible modes of the operation;• For the purpose of training IOHMM models, the training data corresponding to the explanatory variables should be collected;• For the case of multi-level switching signals, discrete HMM models are proposed to be used. Thus, it is necessary to map the distinct non-integer levels of the signals to distinct integers in a one-to-one mapping.