Page 4 of catalogue Capacitive sensors of Rechner Industrie-Elektronik GmbH

TECHNOLOGY
Capacitive sensors, our abbreviation KAS, contain a transistor oscillator which is actuated when a defined capacitance is exceeded by the approach of metals, non-metals or liquids. The smaller its dielectric permittivity εr the closer the medium has to be approached. This effect can also be achieved by detecting through non-metal materials, if the dielectric permittivity of the material to be detected is higher (approx. factor 5). Depending on the type the current change of the oscillator will be amplified to a streamlined output signal or output as a binary signal by a switching amplifier. Output stages with npn or pnp transistors are available for DC operation. A transistor output stage or FET-output is integrated for AC connection

The output switching functions are NO, NC or change-over (antivalent), similar to mechanical switches. Electronic circuits, PLCs, Relays or contactors can be activated directly by capacitive Sensors. The current change in the oscillator is caused without physical contact by the approach of the actuating material to the active area. The damping of the oscillator is possible between the active surface and specified sensing distance (Sn) + 10 %. The RECHNER capacitive sensors with 20-turn spindle potentiometer allow sensitivity adjustment greater or less than the nominal sensing distance. Under the best operating conditions (e.g. constant ambient conditions) a sensing distance up to the maximum specified value can be adjusted. The Components of the KAS are mounted in plastic or metal casings and encapsulated with epoxy casting resin. The plastics used for the housings are: ! PVC (polyvinylchloride), ! PA (polyamide) 6.6 Glass-fibre reinforced ! PA conductive (carboniferous) ! PC (polycarbonate) ! PTFE (polytetrafluor ethylene) ! PEEK (polyetheretherketone)

By means of the following measures all devices are insensitive to dirt, vibration (vibration stability: 30 g, 100...2000 Hz, 1 hour) and are watertight (depending on the type, up to IP 68). The choice of housings enables a wide range of applications, e.g. with aggressive media, in hot areas or in areas subjected to steam. Only pre-tested electronic components, proven integrated circuits and hybrid circuits are used and produced with SMT. The standard constant ambient temperature permitted is -25 up to +70°C, and up to 90°C for brief periods. High-temperature types for use from -200 up to +250°C are also included in our general product line. With contactless detection no physical actuating force is required for operation. There is no contact bounce, no sensor wear, no maintenance and the service life is independent of the switching frequency. KAS can be used in Machines, systems and vehicles for level monitoring of liquids or bulk material, and also through non-metal windows. Further more as Limit switches, contact-less position switches for monitoring and positioning, as Pulse generator for counting tasks, distance and speed measurements and for many other applications (for examples of applications: see page 11).

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RECHNER Industrie-Elektronik GmbH • Gaußstraße 8-10 • D-68623 Lampertheim • Tel. +49 (0) 62 06 50 07-0 • Fax +49 (0) 62 06 50 07-20 • email info@rechner-sensors.de • www.rechner-sensors.de

All specifications are subject to change without notice. (07/2004)

And the metal housings are ! brass / chrome or nickel-plated ! VA stainless-steel, material No. 1.4301 or No. 1.4305. ! Aluminium die-cast