Balluff Gmbh

Horst Siedle Gmbh & Co. Kg

Ernst Ehling

Martin Kurz

Arwed Brunsch

J&uuml;rgen Petrik

Ernst Gass

Andreas Ullrich

Joszef Geisz

A magnetostrictive position measuring system is provided with a waveguide and which is allocated with a magnet movable along the waveguide. An impulse generator for generating an excitation pulse and a conductive wire for guiding the excitation pulse through the waveguide to the magnet are provided, whereby a torsion wave arises in the waveguide when the excitation pulse reaches the magnet. A reel for generating a reply pulse as a function of the torsion wave and a position calculation unit for ascertaining the position of the magnet as a function of the excitation pulse and the reply pulse are provided. A processor is provided in which a table is present in which a large number of positions and excitation pulse correction values are allocated to one another. The duration of the next excitation pulse is altered as a function of the position of the magnet ascertained and the associated excitation pulse correction value from the table.

MAGNETOSTRICTIVE POSITION MEASURING METHOD AND SYSTEM FOR CHANGING A DURATION OF A NEXT EXCITATION PULSE AS A FUNCTION OF THE ASCERTAINED POSITION OF THE MAGNET AND THE ASSOCIATED EXCITATION PULSE CORRECTIVE VALUE

A method of tuning an input signal (S) is described. The method comprises the steps of amplifying the input signal (S) by a gain element () having a variable impedance () associated therewith and thereby generating an output signal (C), comparing the output signal (C) with a reference voltage (V), tuning the variable impedance () such that the impedance is increased if the amplitude of the output signal (C) is smaller than the reference voltage (V), and that the impedance is decreased if the amplitude of the output signal (C) is greater than the reference voltage (V).

Method and apparatus for tuning an input signal

A modular waveguide assembly for use in a position sensor promotes efficient manufacturing, and can be tested and handled separately from the electronics module of the sensor. The waveguide assembly includes a channel having an opening extending along its length, a waveguide located within the channel, a conductor located within the channel, and a mode converter, such as a coil, located within the channel and positioned to generate an electrical signal from a signal traveling along the waveguide. A damping material can be inserted into the channel opening and around a portion of the waveguide such that the material adheres to the waveguide. Preferably, the damping material is at least initially partially flowable, and is then cured. A support sleeve for locating the waveguide can also be included in the assembly, and includes an elongated tubular member comprising an integral piece of flexible material and a plurality of constrictions spaced along its length for locating the waveguide and protecting it from shock and vibration. The assembly can also include a support element for connecting the coil to the electronics module of the sensor. The element can include terminals electrically connected to the coil ends and a bore for receiving the waveguide and conductor. In addition, the waveguide assembly can be pre-calibrated for use with any electronics module by connecting a gain unit, such as a resistor, to the assembly. The gain unit is selected according to the characteristics of the waveguide, such as its length and/or magnetostrictive sensitivity, and can be easily connected to the electronics module for control of the amplification circuitry in the module.

Modular waveguide assembly and method for making the same

Pre-calibrated waveguide assembly and method

A measurement transducer and method is provided which provides a pair of pulses as an output, the measured condition being represented by the time between the pulses, and which includes internal compensation such that the pair of pulses are adjusted to mimic the output of a predetermined ideal transducer. In one embodiment, correction factors are calculated for a magnetostrictive linear position transducer by comparing the transducer output with a position measurement taken by a separate measuring device. These correction factors are stored in a non-volatile memory. Then, during operation of the transducer, a correction factor is selected for each uncorrected measurement and added to the uncorrected measurement to provide a compensated measurement. The compensated measurement is then used to generate a time value using a calculation which includes a predetermined standard waveguide propagation velocity value. The output pulses are then generated based upon this time value, such that the pulses represent a measurement as it would appear if output from an perfectly linear waveguide having the predetermined standard waveguide propagation velocity. Accordingly, the output pulses are linearized and standardized to the predetermined propagation velocity. Thus, the control system (or other electronic circuit) which receives the output pulses need not be re-programed with the propagation velocity of the actual waveguide used in the transducer when the transducer is replaced or otherwise modified. Rather, the control system (or other electronic circuit) can be programmed permanently with the predetermined standard waveguide propagation velocity, and then used with any transducer having such a standardized output.

Method and apparatus for generating transducer output pulses compensated for component variations

A modular waveguide assembly for use in a position sensor promotes efficient manufacturing, and can be tested and handled separately from the electronics module of the sensor. The waveguide assembly includes a channel having an opening extending along its length, a waveguide located within the channel, a conductor located within the channel, and a mode converter, such as a coil, located within the channel and positioned to generate an electrical signal from a signal traveling along the waveguide. A damping material can be inserted into the channel opening and around a portion of the waveguide such that the material adheres to the waveguide. In one embodiment, the damping material is at least initially partially flowable, and is then cured. A support sleeve for locating the waveguide can also be included in the assembly, and includes an elongated tubular member comprising an integral piece of flexible material and a plurality of constrictions spaced along its length for locating the waveguide and protecting it from shock and vibration. The assembly can also include a support element for connecting the coil to the electronics module of the sensor. The element can include terminals electrically connected to the coil ends and a bore for receiving the waveguide and conductor. In addition, the waveguide assembly can be pre-calibrated for use with any electronics module by connecting a gain unit, such as a resistor, to the assembly. The gain unit is selected according to the characteristics of the waveguide, such as its length and/or magnetostrictive sensitivity, and can be easily connected to the electronics module for control of the amplification circuitry in the module.

Modular waveguide assembly for a position sensor and method for making the same

A method and apparatus for calibrating the output signal of a linear position detector without accessing the interior of the detector housing is provided. According to one exemplary embodiment, a magnet is selectively movable toward and away from the exterior of the electronics housing, and a sensor is provided within the housing for sensing the presence of the magnet. According to this embodiment, the linear position detector is calibrated by setting a movable marker at the desired position and pushing the magnet toward the housing. The sensor then detects the presence of the magnet, and a processor saves the position of the marker as a reference point. All future positions of the marker can then be scaled based upon the reference point. Thus, the linear position detector can be calibrated without the need for opening the electronics housing and potentially exposing the electronics components to moisture, contaminants, and/or static electricity. Preferably, the magnet is connected to a push button on a base, and the base includes an attachment mechanism, such as a clip for example, to attach the base to the position detector.

Method and apparatus for calibrating the output signal of a linear position detector

An apparatus and method for automatically and periodically tuning a signal having a gain element, a variable impedance associated with the gain element, and a control device. The gain element has an input for receiving the signal and an output for providing an output signal and is preferably an operational amplifier with a feedback path extending from the output to the input. The variable impedance is preferably connected in series in the feedback path and includes a plurality of resistors connected in series and a plurality of switches, each switch being connected in parallel with one of the resistors. The control device receives the gain element output signal and generates a control signal in response to the amplitude of the gain element output signal. The control signal is transmitted to the variable impedance for regulating the setting of the impedance. Preferably, the control device also includes a pair of comparators for evaluating the gain element output signal and a field programmable gate array for receiving the outputs of the comparators and generating the control signal. The control signal preferably comprises a plurality of switching signals, each signal being connected to one of the switches for controlling the state of the switch.

Apparatus and method for automatically tuning the gain of an amplifier

An overvoltage protection apparatus for use with a data transmission interface, having at least one data transmission line associated therewith, for protecting the interface from power spikes, transients, and/or the continuous application of an excessive voltage. In a preferred embodiment, the apparatus includes at least one voltage limiting device associated with each data line. Each voltage limiting device being connected at one end to the associated data line, and at a second end to a current sensing and switching structure, which is in turn connected to ground. The current sensing and switching structure monitors the current through the voltage limiting device. In the event an excessive voltage is applied to a pin or data line of the interface, the voltage limiting device briefly absorbs the excess power and generates an increased current. This increased current is sensed by the current sensing and switching structure, which responds by opening a switch which disconnects the interface from ground. The current sensing and switching structure automatically reconnects the switch after a preselected time period. The switching structure continues to monitor the current from the voltage limiting device, and open and close the switch, for an indefinite period of time until the excessive voltage condition is removed.

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Neuhausen, Germany

Ernst Ehling