Sensor system for contactless distance measuring
AssigneePrecitec GmbH & Co. KG
InventorsManfred Jagiella, Kilian Barth
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Abstract
A sensor system is disclosed for the contactless measuring of the distance between a sensor body and an object. The sensor body contains an identification resistor, the resistance value of which can be interrogated by a control unit which is connected to the sensor body and which is located outside the sensor body. The interrogation makes it possible to determine whether the electrical connection between the control unit and the sensor body exists or is interrupted. If it is interrupted, this can be detected by the control unit in an unambiguous manner due to the missing connection to the identification resistor, and the control unit can generate an alarm signal in order to avoid faulty positioning of the sensor body relative to the object.
Claims12
A sensor system, for capacitive distance measurement, comprising:
- a sensor body;
- a sensor element arranged at said sensor body for contactlessly measuring a distance between said sensor element and an object;
- a control means for supplying a measuring voltage to said sensor element and for evaluating said measuring voltage for the purpose of determining said distance;
- a cable between said sensor body and said control means which is used for transmitting said measuring voltage;
- and
- an identification resistor having a resistance value and being attached to said sensor body and connected to said cable, said control means being constructed so that it supplies an interrogation voltage, which does not influence said measuring voltage, via said cable to said identification resistor for interrogating said resistance value of said identification resistor,
- wherein said measuring voltage is an alternating voltage and said interrogation voltage is a direct voltage, and further wherein said cable is a coaxial cable having a center conductor and a shield conductor, and wherein the direct voltage and the alternating measuring voltage are transmitted via said center conductor of said coaxial cable and said identification resistor is connected between said center conductor and said shield conductor of said coaxial cable, and wherein said shield conductor is connected to an active shield potential obtained in that the measuring voltage is guided to said shield conductor via an amplifier.
Dependencies are inferred from the claim text.