Capacitive sensors for process control in industrial marble machines

The paper presents the design of capacitive sensors for process control in marble industry, particularly for the contact-less detection of the presence of stone samples under the abrasive/cutting heads in an industrial machine. Different types of sensors are proposed whose performances have been assessed through experimental test campaigns considering real working conditions. Compared to state-of-art sensors the proposed solutions (capacitive sensors plus front-end circuitry) allow for a reliable detection while being of low complexity and robust to harsh environment conditions.