Capacitives with Perspective

Unlike inductive proximity switches, which respond exclusively to metals, capacitive sensors react to a wide spectrum of other materials, such as for example: paper, glass, plastics, oil, water, as well as all metals. The sensor output switches when the object to be detected is within a certain distance to the sensor element. The switching distance is adjustable. To change the switching distance the potentiometer of conventional sensors is located in the sensitive oscillator range. This however makes the sensor extremely sensitive to HF-input sources and other events. By removal of the potentiometer from the oscillator section to a much more insensitive section of the switching unit Baumer Electric sensors surpass the popular EMV standards to a large extent. The sensors are thereby desensitized as far as HF-, Burst and ESD malfunctions are concerned. It often proves to be difficult to identify highly gloss materials and reflective objects. In such applications photoelectric sensors only have mostly unsatisfactory results. However for proximity switches this does not present a problem. High gloss cellophane coverings and even reflective materials in the background (for example: the metal coating of a compact disk behind transparent protective packaging) have absolutely do not influence the switching behavior.