Abstract: An apparatus for determining and/or monitoring a physical or chemical process variable of a medium, having a sensor unit, which produces a measurement signal with a piece of process variable-dependent, basic information, and having an evaluation unit which, from the measurement signal of the sensor unit, determines a measured value for the process variable, and which produces an output signal with information concerning whether the measured value is greater or smaller than a limit value. A first and second modulation range are provided, and the evaluation unit modulates the output signal within the first or second modulation range with the basic information of the measurement signal, with the evaluation unit modulating the output signal within the first modulation range when the process variable is smaller than the limit value, and with the evaluation unit modulating the output signal within the second modulation range when the process variable is greater than the limit value.

Abstract: Disclosed is a device for determining and/or monitoring a predetermined level. The multipurpose inventive device comprises the following: a mechanical oscillating structure which is placed at the same height as the predetermined level, a pot-shaped housing which is sealed on one end by a membrane (3), piezo-electric elements (15,17) which are arranged in a pile (13) and which, when in operation, are used to place the oscillating structure in an oscillating state, in addition to detecting oscillations according to a momentary level and to make said oscillations accessible for further processing and/or evaluation, being confined between a first and second die (19,21) whose respective ends are adjacent to the pile (13), wherein the pile (13) is clamped along the longitudinal axis of the housing (1) between a pressure screw (24) which is screwed into the housing (1) and the membrane (3).

Abstract: An electrotechnical device is provided, having components connected by means of plug connections. The interior of the device is filled with a casting material. The device includes: a housing; arranged in the housing a first components which has at least one terminally-protruding contact pin; a second component which has a socket on which terminally-located contact plugs are provided for receiving the contact pins; and an insert in which the first component is arranged. The insert includes a secluded chamber which has an opening into which the socket of the second component is introduced. The chamber additionally includes a rear wall lying opposite the opening through which the contact pins are stuck into the contact plugs of the socket. An air-tight seal exists between the contact pins and the rear wall. The housing is filled with the casting material from an end lying opposite to the opening of the chamber.

Abstract: An electrotechnical device is provided, having components connected by means of plug connections. The interior of the device is filled with a casting material. The device includes: a housing; arranged in the housing a first component which has at least one terminally-protruding contact pin; a second component which has a socket on which terminally-located contact plugs are provided for receiving the contact pins; and an insert in which the first component is arranged. The insert includes a secluded chamber which has an opening into which the socket of the second component is introduced. The chamber additionally includes a rear wall lying opposite the opening through which the contact pins are stuck into the contact plugs of the socket. An air-tight seal exists between the contact pins and the rear wall. The housing is filled with the casting material from an end lying opposite to the opening of the chamber.

Abstract: The invention relates to an apparatus for monitoring a field device for determining and/or monitoring a physical and/or chemical process parameter of a process medium with a first sealing stage facing toward the process and at least one housing with a predetermined interior volume. The housing is located on the side of the first sealing stage facing away from the process, wherein energy is transferable through the first sealing stage 4 in the direction of the process medium. This energy interacts with the process medium, wherein at least one detector unit is provided in the housing, which unit monitors at least one condition parameter of the interior volume of the housing.

Abstract: In a method of transmitting a measurement signal M between a measuring unit 1 and a control unit 10, the uniform measurement signal has a supplementary signal Z superimposed on it which alternates over time. To check the operation of the measuring unit 1, the measurement signal M is evaluated in the control unit 10. If the supplementary signal Z is erroneous, the control unit 10 produces an alarm signal.

Abstract: Disclosed is a device for determining and/or monitoring a predetermined level. The multipurpose inventive device comprises the following: a mechanical oscillating structure which is placed at the same height as the predetermined level, a pot-shaped housing which is sealed on one end by a membrane (3), piezo-electric elements (15,17) which are arranged in a pile (13) and which, when in operation, are used to place the oscillating structure in an oscillating state, in addition to detecting oscillations according to a momentary level and to make said oscillations accessible for further processing and/or evaluation, being confined between a first and second die (19,21) whose respective ends are adjacent to the pile (13), wherein the pile (13) is clamped along the longitudinal axis of the housing (1) between a pressure screw (24) which is screwed into the housing (1) and the membrane (3).

Abstract: A sensor which includes a sensor section and an electronics section. The sensor section includes a sensor element. The electronics section includes a insert containing electronics. A passageway extends between the sensor section and the electronics section, through which the electronics section is connected to the sensor section. A connection element for the electrical connection of the sensor element of the sensor section to the electronics of the electronics section, which is an integral part of the insert, extends into and seals the passageway. With a sensor in accordance with the present invention, the sensor element is permanently protected against moisture.

Abstract: An apparatus for establishing and/or monitoring a predetermined filling level in a container is described, which apparatus can be used in a wide range of applications, that is to say in many different media, which apparatus comprises: a housing (1), an oscillating element for projecting into the container, a diaphragm (5), which is fixedly clamped into the housing (1) at its edge and to which the oscillating element is fastened, and an electromechanical transducer for exciting the diaphragm (5) to produce oscillations in dependence on a transmission signal (S) present at the transducer and for receiving and converting oscillations thereof into an electrical reception signal (E), in which a percentage interval between a resonant frequency fr and an antiresonant frequency far divided by the resonant frequency fr exceeds 20% when the oscillating element oscillates in air.

Abstract: An apparatus for establishing and/or monitoring a predetermined filling level in a container is described, in which a fixed phase difference (.DELTA..phi..sub.R), which is independent of the oscillation quality of the apparatus, exists between a transmission signal and a reception signal (E) at the resonant frequency (f.sub.r) of the mechanical oscillatory structure. This apparatus comprises a mechanical oscillatory structure (1), an electromechanical transducer (2) having at least one transmitter (23) and a receiver (24), an evaluation unit (9), which determines the frequency of the reception signal (E), compares it with a reference frequency (f.sub.R) and generates an output signal which indicates that the mechanical oscillatory structure (1) is covered by a charge material if the frequency has a value which is less than the reference frequency (f.sub.

Abstract: The electronic enclosure for an electronics assembly belonging to an electrotechnical apparatus. The enclosure having one open end situated at the top in a filling position, through which a fluid potting compound is filled and which is closed off by a plug after filling of the potting compound. In the electronic enclosure a spill tube is disposed, the top end of which is located in the filling position level with the desired filling height in the electronic enclosure and the bottom end of which is in communication with a catchment space for the spill quantity of the potting compound flowing into the spill tube.

Abstract: The electronic switching device serves to control the connection of a load to a voltage source by a switch which is controlled in a first operating mode directly by a binary signal furnished by a signal processing circuit and in a second operating mode inverted. The switching device has three terminals, of which the first permanently remains connected to a first terminal of the voltage source and to a first terminal of the load, whilst of the other two switching device terminals the one is connected to the second terminal of the voltage source and the other to the second terminal of the load. The switching device is configured so that it can be changed over from the one operating mode into the other by interchanging the connections between these two other switching device terminals and the second terminals of the voltage source and of the load, respectively.

Abstract: The determining and/or monitoring of a predetermined level of material in a container is implemented with the help of a level sensor having a mechanical oscillatory structure, an electromechanical excitation transducer and an electromechanical reception transducer. The reception transducer is connected to the input of an amplifier circuit, to the output of which the excitation transducer is connected, so that the mechanical oscillatory structure is excited to oscillate at its self-resonant frequency. The mechanical oscillatory structure is mounted at the height of the predetermined level of material in such a way that it comes into contact with this material when said material reaches the predetermined level, which causes the self-resonant frequency to change. The change in the self-resonant frequency is detected by an evaluation circuit connected to the output of the amplifier circuit.

Abstract: The device for determining and/or monitoring a predetermined level of contents in a container comprises a sensor, which is so mounted on the container at the level of contents to be monitored that it comes into contact with the contents of the container when the same reach the predetermined level. The sensor is excited to mechanical vibrations at its natural resonant frequency by an exciting arrangement. An evaluating circuit serves for causing indicating and/or switching operations in a manner dependent on whether the frequency of the mechanical vibrations of the sensor is higher or lower than a switching frequency. Associated with the sensor is an electrical circuit element which has a characteristic parameter, whose value bears an unambiguous relationship to the natural resonant frequency of the sensor. In the evaluating circuit the switching frequency is set in accordance with the value of the characteristic parameter of the electrical circuit element.

Abstract: The electronics enclosure comprises, surrounded by a metal shroud, an open end closed off by a plug of insulating material fitted in the metal shroud, in which contact members are provided for connecting the electronics assembly accommodated in the electronics enclosure to outer connecting leads. One of the contact members is a grounding contact member including a ring on which radially protruding spring claws of elastic material are provided. The plug is provided with a peripheral groove, and the ring of the grounding contact member is applied level with the peripheral groove in the plug such that the spring claws protrude into the peripheral groove. The length of the spring claws is dimensioned so that on insertion of the plug in the metal shroud they are flexed in the metal shroud and come into spring contact with the inside surface of the metal shroud.

Abstract: The determination and/or monitoring of a predetermined material level in a container is effected with the help of a material level sensor which contains a mechanical oscillatory structure, an electromechanical excitation transducer and two electromechanical reception transducers. The mechanical oscillatory structure is secured at the height of the predetermined material level in such a way that it comes into contact with the material when said material reaches the predetermined material level. Each reception transducer is connected to the input of an assigned circuit channel, which contains an amplifier circuit, the output of which is connected to the excitation transducer and which is so constructed that the mechanical oscillatory structure is excited to produce oscillations with its natural resonance frequency. The two circuit channels are activated alternately by means of a control circuit.

Abstract: The apparatus comprises at least two oscillating rods which are secured spaced from each other to a diaphragm, the edge of which is connected to a screw-in piece. On the side of the diaphragm remote from the oscillating rods a clamping screw is fixedly connected to the diaphragm so that the clamping screw and diaphragm assume a position with respect to each other in which the axes of symmetry coincide. The clamping screw is surrounded by a stack of annular piezoelectric elements, electrode rings and insulating rings. The stack forms the excitation and receiving transducer of the apparatus. The stack-shaped excitation and receiving transducer is clamped and secured between the diaphragm and a hexagonal nut. The stack bears on pressure studs which are arranged between a metal ring terminating the stack and the diaphragm. The clamping force is chosen so that the diaphragm is simultaneously concavely prestressed.

Abstract: The device for determining and/or monitoring a predetermined filling level in a container has two oscillatory rods secured with spacing adjacent one another on a diaphragm the edge of which is connected to a screw-in part. By means of the screw-in part the device is so secured in a screw-threaded aperture of the container wall at the height of the filling level to be detected that the oscillatory rods project into the container. At the side of the diaphragm remote from the oscillatory rods a bridging member is held spaced from the diaphragm by flexurally elastic rod-shaped supports. Each of the rod shaped supports is rigidly connected at one end to an oscillatory rod. Between the bridging member and the diaphragm there is held, with preloading of the diaphragm, a transducer column comprising in a stack a piezoelectric excitation transducer and a piezoelectric reception transducer.

Abstract: Disclosed is a capacitance level measuring device comprised of a container whose level is to be measured and a probe inserted into and spaced from the container. The capacitance between the probe and container varies in relation to the level in the container. A capacitance measuring circuit determines the capacitance between the probe and container and thus indicates the level in the container. The integrity of the probe is verified by constructing the probe so as to include it in a series circuit, as well as the capacitance measuring circuit, and a lack of continuity in the probe is indicative of questionable probe integrity. The question as to the probe's integrity would indicate a questionable level indication from the capacitance measuring circuit. Various probe constructions are also disclosed.

Abstract: An arrangement for determining the level in a container includes a capacitive probe disposed in the container, a measuring transducer arranged in the vicinity of the container, and a remote evaluation apparatus. The measuring transducer produces a signal corresponding to the capacitance between the probe and the container. This signal, which is indicative of the level in the container, is transmitted from the transducer to the evaluation apparatus via a two-wire line, which also transmits the current supply DC voltage from the evaluation apparatus to the transducer. The transducer includes a switch for periodically switching from the probe capacitance to a test capacitance. The evaluation apparatus comprises a time control circuit which periodically varies or interrupts the DC voltage on the two-wire line, and the transducer includes a control circuit which responds to the voltage changes to actuate the switch.