Micro-epsilon Messtechnik Gmbh & Co. Kg

Ringspann Gmbh

Micro-epsilon Messtechnik Gmbh & Co.

Micro-epsilon Messtechnick Gmbh & Co. Kg

Franz Hrubes

Karlheinz Timtner

Karl Wisspeintner

Norbert Reindl

Günter Schallmoser

A circuit arrangement () for controlling an inductive displacement measurement sensor () is described. The displacement measurement sensor has a sensor coil (), which is supplemented by means of a capacitor (C) to form an oscillating circuit. In addition, the circuit arrangement has an oscillator () for generating an excitation signal (U), which excites the oscillating circuit to oscillate. The excitation signal (U) is superimposed with a DC voltage (U), the amplitude of which changes when the temperature of the sensor coil () changes. The sensor coil () is connected to a controllable resistor (R). Furthermore, the circuit arrangement () has a comparator (), which compares the DC voltage (U) with a reference voltage (U). On the basis of the result of the comparison, the comparator () outputs a control voltage (U), which controls the controllable resistor (R). In a further development of the circuit arrangement the control of the controllable resistor (R) is designed in such a way that when the temperature of the sensor coil () changes and, as a result, the ohmic resistance (R) of the sensor coil () also changes, the total resistance consisting of the sensor coil (R) and the controllable resistor (R) is held essentially constant.

Circuit arrangement and method for controlling a displacement measurement sensor

A position sensor that includes two coils, the first coil (transmitting coil) being fed a certain frequency such that it emits a constant electromagnetic field, and said field being received and/or detected by way of the second coil (receiving coil), is characterized in that the axis of the second coil is angled with respect to the axis of the first coil, preferably located at an angle of 90&#xb0; with respect to the axis of the first coil.

Position sensor

The invention relates to a circuit for adjusting an impedance between two terminals, said impendance including the input impedance of the circuit. The aim of the invention is to enlarge the adjustment range and to stabilize&#x2014;the operating behavior of such a circuit. For this purpose, the circuit comprises amplifiers, adjusting means with which amplification of at least one amplifier and/or the circuit can be changed in general and the impedance between the two terminals can be modified by influencing the one or more adjusting means.

Circuit for adjusting an impedance

The invention relates to a contactlessly working eddy current sensor, particularly for detecting essentially flat test objects, comprising at least one sensor coil, eddy currents being able to be induced in the test object. The invention is characterized in that the coil, when passing by the test object, is aligned in such a manner that the coil axis is oriented essentially parallel to a line normal to a surface to the test object, and that the test object can be moved past the sensor coil essentially parallel to the coil axis or the sensor coil can be moved past the test object. A corresponding method is carried out so that an eddy current can occur only once when the test object or coil is passed by.

Contactless eddy current sensor and process for detecting test objects

A process and a device for contactless measurement of rotational speed with a proximity sensor operating according to the eddy current principle. The proximity sensor comprises an inductor and a capacitor connected in parallel that form an oscillating circuit which can be excited from outside, and where the resonant frequency of the oscillating circuit experiences a detectable change when an object to be measured approaches the proximity sensor. In various embodiments, the resonant frequency of the oscillating circuit or the excitation frequency of the oscillating circuit is controlled as a reaction to slow changes of the resonant frequency in such a manner that the oscillating circuit is always excited with its resonant frequency or with a frequency close to its resonant frequency and that rapid changes are detected as a measurement signal for the measurement of rotational speed.

Process and device for contactless measurement of rotational speed

Measuring device and method for determining the position of an electrically conductive test object () with a noncontacting sensor, in particular an eddy current sensor (), wherein the test object () is adapted for linear reciprocal movement in a predetermined direction. The test object () includes a marking (), and the sensor is arranged transversely to the direction of movement of the test object () and at a constant distance from the test object in the region of the marking (), so that a movement of the test object causes the sensor to produce an at least largely linear signal change over a predetermined measuring range.

Measuring device and method for determining the position of an electrically conductive test object

A method for linearizing a nonlinear curve with a linearization circuit (), wherein the curve represents the relationship between input signals and output signals of a sensor. An output signal () of the sensor, which is respectively associated with an input signal, is displayed with respect to a simple and cost favorable linearization such that the adjustment of the linearization circuit () essentially occurs in an automated way utilizing sequence controller (). A corresponding circuit is also described for practicing the method.

Method and circuit for linearizing nonlinear curves

A circuit () for compensating for temperature with a sensor operating by the eddy current principle for measuring physical conditions of an object. The circuit includes an evaluation unit () for evaluating a measuring signal () of the sensor (). The sensor () and the evaluation unit () are interconnected via a connection cable (). For the purpose of minimizing or preventing to the greatest extent temperature caused interferences, an additional compensation line () is provided which compensates for the temperature of the connection cable (). A corresponding method for compensating for temperature is described.

Circuit and method for compensating for temperature

A sensor arrangement with a first sensor ( ) which comprises a measuring coil ( ) that operates by the eddy current principle, and which detects the distance from a target ( ), and a second sensor ( ), the two sensors ( ) being arranged in a housing ( ). To reduce the interaction of the sensors with each other, a panel ( ) is positioned on the measuring side of the housing, with the panel being an active component of the second sensor ( ). The second sensor is preferably a capacitive sensor, with the panel ( ) being the active measuring surface of the capacitive sensor.

Sensor arrangement for detecting properties of a target

A torque transmitter comprising two members 1, 2 rotatable relative to each other and serving to transmit a torque, and which has the ability to continuously measure the transmitted torque. The transmitter includes a transducer ring 3, and a displacement measuring device 6 having at least two noncontacting sensors 4, 5 for detecting the axial position of the transducer ring 3 relative to a reference member 7. The members 1, 2 are inter-connected via transverse beams and connected with the transducer ring 3 via fork-like members, so that upon a torque being transmitted between the members 1, 2, the latter are rotated relative to one another proportionally to the torque, and the transducer ring 3 is axially displaced. To achieve an error-free and reproducible determination of the torque, the transducer ring 3 and the reference member 7 are provided with surfaces 8, 9 which are substantially parallel to each other and axially aligned with each other, and the sensors 4, 5 occupy a fixed position and are arranged such that they measure against the surfaces 8, 9 either in a direction opposite to each other or toward each other.

Torque transmitter

Noncontacting displacement measuring system having an electric field

A method of error compensation for transducers having non-linear characteristics is shown. A computer-supported measuring circuit is used. In a first factory alignment, the output characteristic of the transducer is set so that it can be linearized by the computer using a power function. The appropriate exponent of the power function is stored. At the place of use, at least three calibration measurements are performed with the installed transducer using defined calibration measured values substantially spanning the measuring range of the transducer equidistantly. The power function is solved with the calibration measuring results and the stored exponent, so that the constants not yet known can be calculated. During every following service measurement, the actual measuring result is put into the now solved power function. The result of the equation is then outputted as the error-compensated measuring result.

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Rotthalmünster, Germany

Franz Hrubes