Endress+hauser Gmbh+co.

Endress + Hauser Gmbh + Co. Kg

Other

Endress+hauserse+co. Kg

Bernd Strutt

Volker Dreyer

Bernhard Michalski

Christoph Schleith

Robert Lalla

Herbert Schroth

Wolfgang Brutschin

Roland Muller

Udo Grittke

Jurgen Meier

Martin Pfandler

Ralf Armbruster

A field device has a housing providing EMC-protection. The housing includes a conductive housing core, which is surrounded on all sides by a non-conductive housing jacket secured thereon by force-interlocking, e.g. frictional interlocking, or by material bonding. At least one electrically conductive barrier is placed on and connected with an electrically conducting region of the housing core and divides the interior of the housing into at least two chambers with different degrees of EMC-protection. The barrier contains a passageway, with which at least a first electronic circuit and a second electronic circuit, which are located in different chambers, are contacted with one another. The circuits are contacted by spring contacts against regions of the housing core, which are led through the housing jacket into the interior, wherein transitions to a sensor&#x2014;or lid in the housing by means of screw thread&#x2014;and/or wiping contacts are so arranged that these kinds of components are electrically connected with the housing core and wherein seals of the transitions protect against environmental influences.

Field device for use in process automation

A circuit arrangement for the protection of at least one component of a two wire electrical current loop, which is connected in series with a burden to an AC/DC electrical current source. The two wire electrical current loop has a rectifier a clock signal producer and a switch. The rectifier forms a DC circuit, wherein the component is connected in the DC circuit and wherein the clock signal producer outputs a clock signal to the switch for clocking the DC circuit. The circuit arrangement has a diode, wherein the conduction direction of the diode points from the anode of the diode to the cathode of the diode. The cathode of the diode is connected to the DC circuit, and the anode of the diode is supplied with a periodic or constant voltage from a first voltage source, and the voltage is at least periodically greater than a predetermined threshold value.

Circuit arrangement for the protection of at least one component of a two wire electrical current loop

A measuring device, comprising: an input circuit having a supply line and a return line. Energy supply occurs over a line-pair. Input voltage is applied to the measuring device via the line pair. A series regulator for controlling an electrical current flowing via the line-pair, a shunt regulator installed in a parallel branch, and an apparatus for controlling a voltage drop across the series regulator are provided.

Measuring device for measuring a precess variable in industrial measurements and control technology

An apparatus for determining a physical process variable of a medium (,) which can be used in conjunction with various sensor types, the sensors having in common that they determine a process variable by means of a delay-time method. The apparatus has a sensor (,), a sensor-specific application unit (,) and an evaluation unit (,), which is essentially independent of the sensor type used, the sensor (,) being assigned a transmitting/receiving unit (,), the transmitting unit (,) transmitting measuring signals in the direction of the medium (,) and the receiving unit (,) receiving the measuring signals influenced by the interaction with the medium (,), and the application unit (,) being designed in such a way that it provides measurement data, independently of the type of sensor (,) used, from which the evaluation unit (,) determines the physical process variable using a delay-time method by means of a uniform evaluation algorithm.

Apparatus for determining a physical process variable of a medium

The transducer supply is configured for supplying a passive transducer arranged in an explosion-hazard zone with electrical energy from a DC voltage source. The electrical energy is transmitted via a two-wire connection, via which in the opposite direction the measured value sensed by the transducer is transmitted by the transducer setting the direct current obtained from the DC voltage source to a value variable between two limit values. As a means of protection a transformer is inserted in the two-wire connection which affects DC decoupling. The direct current is chopped in accordance with the principle of a DC voltage converter at the primary side of the transformer and re-rectified on the secondary side. To permit connection of an active transducer instead of a passive transducer, the active transducer having its own energy supply and furnishing at its output connections a direct current in a quantity representing the measured value, an adapter circuit controlled by the output current of the active transducer is inserted between the output connections of the rectifier circuit and the connecting terminals provided for connecting the active transducer, this adapter circuit loading the rectifier circuit with a direct current which is proportional to the output current of the active transducer.

Transducer supply

A level measuring device suitable for highly accurate measurements. A transmission pulse generator generates microwave pulses at a transmission repetition rate and transmits them through an antenna towards a material whose level is to be measured. Echo signal from the surface of the material are received by the antenna. A reference pulse generator generates reference pulses similar to the transmission pulses but at a reference repetition rate which differs from the transmission repetition rate by a small frequency difference. The echo signal and reference pulse are input to a first mixer which generates an intermediate frequency signal that, with respect to the echo signal, is slowed by a time dilation factor equal to the quotient of the transmission repetition rate and the frequency difference. A first subcircuit samples the intermediate frequency signal, the time interval between two successive samplings equaling a time unit. A differential signal generator generates a differential signal which changes with the frequency difference. A second subcircuit determines the period of the differential signal on the basis of the time unit. An evaluation unit determines an actual time interval between two points of the echo signal corresponding to the two sampling points.

Level measuring device operating with microwave

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.

Electronic switching device

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. Furthermore, each circuit channel contains a measuring signal transducer which produces a measuring signal which on the one hand contains the information about the frequency of the output signal of the amplifier circuit, and to which on the other hand an identifier assigned to the circuit channel has been added, said identifier being different from the identifier assigned to the other circuit channel.

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Steinen, Germany

Bernd Strutt