Sensor Placement for Diagnosability Analysis in Thermofluid Processes

system in process engineering´s safety is based on a monitoring system characterized by its ability to detect and to isolate faults. Considering single faults diagnosis, the existent monitoring systems treat only one category of additive faults at a time (actuator faults or sensor faults). The present paper considers thermofluid processes; the main objective is to identify the category of components (hydraulic actuators, thermal actuators, hydraulic sensors and thermal sensors) to which belongs the faulty element. Then one can seek the fault in the right category thanks to the existing methods. The innovative interest is thus to be able to isolate two component faults of different categories. On a second time, the set of thermal sensors is considered and an important result on their diagnosability is deduced. An application to an interconnected network of components in a thermofluid installation illustrates our results.