Ifm Electronic Gmbh

Werner Hoch

Walter Reichart

Jochen Gundlach

Christian Kreisel

Sebastian Liehr

Markus Körber

Ralf Kriesen

Jaromir Palata

Alfred Wagner

Joerg Schulz

Markus Von Ehr

Francesco Bernd

The invention relates to a method for the contactless tapping of communication signals that are exchanged between two communication units, in particular a sensor or actuator and a digital evaluating or control unit, wherein the communication signals are transmitted on a line () of a multi-core cable () as voltage signals. According to the invention, in order that the communication signals can be tapped also in the case of multi-core cables without the line having to be interrupted for this purpose, the communication signals are tapped capacitively, wherein at least two electrodes (), which lie on the cable sheath and the angular position of which in relation to the cable axis is variable, are used for the tapping and the angular position at which the differential signal between the two electrodes () is maximized is determined, wherein the at least two electrodes (), each consisting of a plurality of individual electrodes (E-E), are designed as collection electrodes and the various angular positions of the collection electrodes () are achieved in that the association of the individual electrodes (E-E) with the at least two collection electrodes () is sequentially changed by means of a controller (). The invention further relates to an assembly for performing said method.

Method for the contactless tapping of communication signals

Fill level measuring device having a control unit, which contains a high-frequency generator for generating a transmission signal, an amplifier, an amplifier and an evaluation unit, and a spatially remote probe, which contains a measuring impedance, a reference impedance, a first rectifier and a second rectifier, as well as a connecting line between the control unit and the probe, wherein the rectifier detects the voltage of the transmission signal in the probe, and this voltage is transmitted to the control unit as a first DC voltage signal, and the rectifier converts the probe current in the probe into a second DC voltage signal via measuring resistors, and both signals are supplied to the control unit for the purpose of determining the fill level, wherein the rectifiers are thermally coupled to one another.

Fill level measuring device

A magnetoinductive flowmeter for measuring the flow rate of a flowing, conductive medium with a capacitive measuring apparatus for detecting empty pipes is provided. In order to improve the detection of empty pipes and, in particular, the capacitive coupling to the medium, the invention provides for the measuring apparatus for detecting empty pipes to comprise a sheet-like electrode in each case and a counterelectrode which form a measurement capacitance Cwhich is dependent on the medium and on the degree of filling of the measuring tube; for the measuring tube to have a wall thickness which is reduced in order to maximize the measurement capacitance Cat least in the region of the electrode and the counterelectrode; and for the measuring tube to be surrounded by a metal supporting housing, wherein, in order to maintain the pressure resistance of the measuring tube, a hollow-walled supporting body for minimizing the influence of parasitic capacitances on the measurement capacitance Cis arranged in each case in the region of the reduced wall thickness between the electrode and the inner wall of the supporting housing and between the counterelectrode and the inner wall of the supporting housing and supports the measuring tube against the supporting housing in each case.

Magnetic inductive flow meter having capacitive measuring device for empty pipe detection

A magnetic-inductive flowmeter with a nonconductive measuring tube, a magnetic field generating apparatus, two measuring electrodes conductively coupled to the medium for tapping a measuring-circuit voltage induced in the flowing medium, and with a measuring device for detecting an empty tube. Detection of an empty tube is obtained by the measuring device being an admittance measuring device having a detector, a counter-electrode, an ac signal source and an evaluation unit, the detector having an electrode connected to the ac signal source so that the electrode is exposed to an ac signal in the range of roughly 50 MHz-200 MHz and then an electrical field extends from the electrode into the medium. The electrode of the detector and the counter-electrode planiform shaped and are located essentially opposite one another on the outer surface of the measuring tube above and underneath the longitudinal axis of the measuring tube, respectively.

Magnetic-inductive flowmeter with an empty tube detecting device of an admittance measuring type

A circuit arrangement is described for detecting the capacitance or change of capacitance of a capacitive circuit element or of a component, specifically of a sensor capacitor (), with a control unit () ,with a monostable multivibrator () triggered by the control unit (), and with an evaluation unit (), the monostable multivibrator () having a first input () which is connected to the control unit (), a second input ()which is connected to the sensor capacitor (), and one output (), of the monostable multivibrator () is triggered by the control unit () at the output () of the monostable multivibrator () an output signal or output signals appearing, with a time duration which is proportional to the capacitance of the sensor capacitor (), the output signal or output signals of the monostable multivibrator ()being converted into a signal voltage proportional to its or their duration, and in the evaluation unit () a detection value corresponding to the capacitance or change of capacitance of the sensor capacitor () being obtained from the signal voltage, The circuit arrangement as claimed in the invention is improved compared to the prior art in the output () of the monostable multivibrator () is connected upstream of a constant current generator () which can be controlled by its output signal or output signals and that an integrator () which converts the current delivered from the constant current generator ()into the signal voltage is connected to the constant current generator ().

Circuit arrangement for detecting the capacitance or change of capacitance of a capacitive circuit element or of a component

A device for measurement and detection of the level of a medium in a container with a sensor element, with a reference element and an electrical circuit which contains at least one AC voltage source and an evaluation unit, the sensor element and the reference element being arranged such that the medium to be measured or detected influences the impedance between them. The capacitive level measurement and detection device has an AC voltage source that supplies a high-frequency voltage or a voltage with high frequency voltage portions. The circuit which has the AC voltage source, the sensor element and the reference element has an impedance which is as low as possible. The electrical circuit can have an amplifier, a timer, a pulse shaper, a first synchronous rectifier, a first I/U converter, a microcontroller, a reference impedance, a second synchronous rectifier and a second I/U converter.

Capacitive level measurement and detection device using high frequency voltage

A capacitive fill level measuring instrument includes a fill level sensor having several sensor arrays ( ), electrical lines ( ) connected to the sensor arrays ( ), select switches ( ) with multi-pole sides ( ) connected to the lines ( ), and a power supply and evaluation circuit ( ) having a power supply circuit ( ) and an evaluation circuit ( ) connected to the mono-pole sides of the select switches ( ). A measured value is determined for a state in which no sensor array ( ) is connected via the evaluation circuits ( ) and ( ), the sensor arrays ( ) are alternately connected to the multi-pole side ( ) of the first select switch ( ) and the multi-pole side ( ) of the second select switch ( ), and after a first fill level determination, the sensor arrays ( ), adjacent to a boundary layer, are triggered or interrogated, advantageously, solving various problems with background art devices.

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Tettnang, Germany

Werner Hoch