Quality-Related Fault Subspace Extraction for Fault Diagnosis

Several complex process monitoring approaches introduced in previous chapters can be used to determine whether the system is abnormal. However, once a fault has been detected, it is important to diagnose the root cause and identify the fault type. Since it can extract information related to output variables and infer the quality variables from the input variables, PLS has been applied to the diagnosis of key performance indicators by analyzing process variables. In the chapter, input variables refer to the process variables measured online and output variables refer to some key performance indicators (KPI).