| 摘要 |
The invention relates to an inductive proximity switch having a current-fed resonant circuit comprising at least one resonant circuit transmitting coil and a capacitance. The resonant circuit transmitting coil generates an alternating magnetic field, which is able to induct a mutual induction voltage in at least one receiving coil, and the oscillation state of the resonant circuit can be influenced by a metallic release entering or moving away from the alternating field, having an evaluating circuit for obtaining a switching signal from the change in the oscillation state of the resonant circuit, the change in the complex coupling between the at least two coils, namely transmitting coil and receiving coil, being evaluatable with the aid of an auxiliary voltage signal as a switching signal in the presence or absence of the release. |
| 主权项 |
1. Network for the operation of an inductive proximity switch,
the network having a current-fed resonant circuit comprising a resonant circuit transmitting coil and a capacitance, and the resonant circuit transmitting coil generating an alternating magnetic field for inducing a mutual induction voltage in at least one receiving coil, and an oscillation state of the resonant circuit is influenced by a metallic release entering or moving away from the alternating magnetic field, and from a change of the oscillation state of the resonant circuit is obtained a switching signal, a change of a complex coupling between the at least two coils, namely transmitting coil and receiving coil, being evaluatable as a switching signal with aid of an alternating auxiliary voltage in a presence or absence of the release, wherein the alternating auxiliary voltage signal is obtained as a partial voltage from an alternating resonant circuit voltage of the resonant circuit of the network in a presettable ratio, a complex voltage divider resulting from a series connection of two complex resistors is connected in parallel to at least one of the transmitting coil and capacitance of the resonant circuit, wherein the alternating auxiliary voltage signal falls across one of the complex resistors, the alternating auxiliary voltage signal being connected in series with the mutual induction voltage induced in the receiving coil such that a differential voltage to ground or to a potential is obtained at an output of the receiving coil, wherein a value of the differential voltage is reduced by the alternating auxiliary voltage signal compared with the induced mutual induction voltage, the switching signal being generated from the differential voltage, an evaluating circuit for obtaining a switching signal from the change of the oscillation state of the resonant circuit, wherein the auxiliary or differential voltage, respectively, is obtained by a correspondingly positioned tap through a tapping point on the transmitting coil, the tapping point subdividing the transmitting coil into the partial inductances. |
