A sensing system and method. A coded wheel is configured to generate a signal that varies with rotation of the coded wheel. A sensor is configured to sense the varying signal and output a corresponding signal. A correction module is configured to receive the signal output by the sensor and compare the received signal to a stored signal and detect a defect in the coded wheel in response to the comparison.

Rotation sensing method and system

A method of controlling motor speed. The motor speed control apparatus includes an encoder in mechanical association with the motor. The encoder has one channel providing an encoder signal having a rising and falling state transition for each period of the encoder signal. The periodic frequency of the state transitions are used to precisely measure instantaneous motor speed. A comparitor then compares the periodic frequency with a predetermined motor speed to provide an error signal, representative of the difference. A feedback control system affects the motor speed dependent on the error signals. In a further embodiment, the encoder includes two channels and four state transitions.

Method for controlling motor speed

Techniques for coupling with devices that convert displacements into differential voltages and improve the sensitivity of such devices The disclosed system improves the accuracy and resolution of a transducers such as an LVDT by converting certain parts of the circuit to a digital circuit One embodiment uses a processor 80, although other digital processing circuitry may also be used

Linear Variable Differential Transformer with Digital Electronics

Active sensor (1) for changing over to a special operating mode, wherein the sensor (1) has at least one sensor element (2), an evaluation circuit (3) and two connecting lines (4, 5) with a respective connection (41, 51) for transmitting the sensor-related information, wherein the supply voltage of the sensor (1) is present on these two connecting lines, wherein the sensor (1) comprises a changeover module (6), which can be used to change over between a normal operating mode and a special operating mode by the reversal of the polarity of the supply voltage present at the two connections. The invention furthermore relates to a method for driving an active sensor and to the use of the sensor (1), in particular as wheel rotational speed sensor, in motor vehicles.

Active sensor with operating mode changeover

The rotation angle detecting device includes a target of a spur gear shape made rotatable together with a rotary member and having a plurality of teeth of magnetic members protruding at a substantially equal pitch in the circumferential direction of the axis of the rotary member, and magnetic sensors arranged at positions to confront the teeth for outputting output signals according to the rotation of the rotary member. This device detects the angle of rotation of a rotary member with the output signals from the magnetic sensors. In the target of the spur gear shape, moreover, the two circumferential end portions of the crests of all the teeth are formed into angular portions.

Rotation angle detecting device and torque detecting device

A method and a device for detecting rotational speed with an inductive sensor in which a sinusoidal potential is induced by a magnet wheel and then fed to a filter with a comparator connected downstream of the filter and therefrom into a square-wave signal that is essentially proportional to the rotational speed of the magnet wheel. This output signal of the comparator is evaluated in a microcomputer. In this evaluation, only the same type of edges of the comparator signal are evaluated, specifically those in which the intervals fluctuate less when considered over a certain time span. The microcomputer here can initially evaluate both types of edges, that is, positive and negative edges, and then use those edges in which smaller fluctuations, that is, interference, are determined for calculating the rotational speed. The microcomputer can also first evaluate only one type of edges and change over to edges of the other type only if the former displays interference above a present value. If the edges of the other type show even greater interference than those of the first type, then the system switches back to the first type. The changeover can be done either in the microcomputer or externally. The external changeover to the type of edge can be done by an external inverter or by reversing the polarity of the sensor output signals by means of a controllable switch.

Circuit for mooting broken or chipped teeth of encoder wheels via comparing temporal fluctuations between rising or falling edges and using edge with least fluctuation

The RPM determination involves an inductive sensor (2) held near a toothed magnetic disc (1), the sinusoidal output of which passes through a filter (3) and a comparator (4) to produce a rectangular signal, which is fed into a calculation unit (5). This unit has logic devices (7,8) for evaluating the time separation between similar flanks, and a switching arrangement (6,11) for switching to measurement between opposite flanks if the time separation deviates by more than a preset amount. The similar flanks e.g. intervals of negative flanks are evaluated for determining the rpm, the time intervals of which fluctuate by less than a determined amount during a specified time duration . Both flanks of the rectangular wave signal are tested, and those synonymous flanks for evaluating the computing of the rpm are selected where the time interval fluctuation is less than that of the opposing flanks during a specified time duration.

Method and apparatus for measuring speed of rotation

of EP0553451With the present invention, a process and a means for carrying out this process are explained, with the aid of which the functioning of at least one electromagnet can be monitored. In particular, two different circuits are indicated, one performing an integration of the counter-electromotive force on de-activation of the electromagnet to be monitored and the other circuit measuring the peak values of the current through the free-running path of the electromagnet (2) and feeding the measurement result in converted form to a microcomputer (12). Furthermore, the operating voltage UB is measured and taken into account in a correction calculation so that fluctuations in the operating voltage have no effect on the evaluation of the functioning or operational reliability of the electromagnet (2).

Günther Gschossmann

Papers

Circuit for mooting broken or chipped teeth of encoder wheels via comparing temporal fluctuations between rising or falling edges and using edge with least fluctuation

Method and apparatus for measuring speed of rotation

Device for monitoring the functioning of inductances