An absolute position encoder for a measuring instrument, comprising a digital scale and a reader movable relative to the digital scale. The digital scale is arranged along a travel direction of the reader. The digital scale comprises at least one absolute position track having a sequence of discrete regions sharply separated from each other by separating regions. The reader comprises a first and a second series of detectors configured to sense the discrete regions and separating regions to detect at least one of a first and a second absolute position code. The sequence of discrete regions and the first and second series of detectors are disposed such that none of the detectors of at least one of said first and second series of detectors is aligned with a transition between a discrete region and a separating region at each possible position of the reader relative to the digital scale.

A movement sensor comprises a multi-pole ring magnet, a semiconductor substrate, a first magnetic sensor formed on the semiconductor substrate, and a second magnetic sensor formed on the semiconductor substrate. The first magnetic sensor is configured to produce a first output signal in response to movement of the multi-pole ring magnet, and a centroid of the first and second magnetic sensors are separate and radially aligned on the semiconductor substrate relative to the multi-pole ring magnet. The second magnetic sensor is arranged at a predetermined angle with respect to the first magnetic sensor and is configured to produce a second output signal in response to the movement of the multi-pole ring magnet. The predetermined angle is between 0° and 90° exclusive and is configured to produce a difference in phase between the first and second output signals in response to the movement of the multi-pole ring magnet.

Provided is a method of estimation of rotor operational characteristics, in particular rotor speed, rotor azimuth and rotation direction, of a rotating rotor of a wind turbine, the method including: measuring pulse rising edge time and pulse falling edge time of pulses generated by each of multiple proximity sensors originating from multiple detection targets arranged on the rotor; estimating values of parameters associated with the sensors and/or targets, in particular parameters associated with the positioning and/or detection range of at least one sensor and/or the parameters associated with the positioning and/or size of at least one target, based on the measured pulse rising edge times and pulse falling edge times; estimating rotor operational characteristics, in particular a rotor speed and/or a rotor azimuth and/or a rotation direction, based on the measured pulse rising and/or falling edge times and/or the estimated values of parameters associated with the sensors and/or targets.

The present invention provides an apparatus for sensing rotor location, the apparatus comprising: a central shaft; a magnet coupled to the central shaft; a sensor portion is disposed correspond to the magnet; wherein the sensor portion comprising a substrate, a first group including a first Hall sensor and a third Hall sensor disposed on the substrate, and a second group including a second Hall sensor and a fourth Hall sensor, the first Hall sensor and the third Hall sensor are arranged to overlap in a radial direction about the central shaft and the second Hall sensor and the fourth Hall sensor are arranged to overlap in a radial direction about the central shaft.

A position-measuring device includes a carrier body having a first and second measuring graduations and a reference mark. The first and second measuring graduations include graduation structures periodically arranged along first and second measurement directions, respectively, that are perpendicular to each other. The graduation structures of the first measuring graduation each extend parallel to a first direction and the reference mark extends in a second direction that forms an angle different from 0° with the first direction. First and second scanners are configured to scan the first and second measuring graduations and generate first and second scanning signals, respectively. A third scanner is configured to scan the reference mark and generate a reference pulse. The position-measuring device is configured such that a phase angle of the reference pulse is determined as a function of the first scanning signals and the reference pulse.

A measuring device for a spindle or for a rotary table includes at least two first and second position sensing elements and a scale element, having a first and second graduations and being rotatable about an axis of rotation relative to the position sensing elements. The first graduation includes regular structures arranged in parallel next to one another along a first direction, having a directional component in the circumferential direction. The second graduation includes regular structures arranged in parallel next to one another along a second direction, having a directional component in the axial direction. The first position sensing elements are offset from one another in the circumferential direction, and are able to scan the first graduation so that the position of the scale element in a plane having an orthogonal orientation to the axis of rotation is determinable. In addition, at least one of the first position sensing elements is able to determine an angular position of the scale element in relation to the first position sensing elements in absolute terms within and across a rotation. The second position sensing elements are offset from one another in the circumferential direction, and are able to scan the second graduation, and the axial position of the scale element is able to be determined.

Methods and apparatus for a magnetic field sensor having first and second arrays of magnetic field sensing elements with at least first and second orthogonal axes of sensitivity. The first array of magnetic field sensing elements is spaced a first distance from the second array of magnetic field sensing elements. A turns counter counts a number of times a magnetic pole pair of a moving target passes the magnetic field sensing elements with a selected pole pair resolution and a module determines absolute angular position of the target from differential signals from the first and second arrays of magnetic field sensing elements and the turns counter. The first distance is configured to match a pitch of the poles of the target.

A detection method includes obtaining first count data and second count data during rotation of an encoder disc mounted at and configured to rotate together with a rotation object and determining a rotation parameter of the rotation object according to the first count data and the second count data. The encoder disc includes N detection target portions arranged along a circumferential direction of the encoder disc. The N detection target portions include N−K first detection target portions and K second detection target portions. Along the circumferential direction of the encoder disc, a width of one of the N−K first detection target portions is different from a width of one of the K second detection target portions. The first count data is obtained when one detection target portion of the N detection target portions is detected. The second count data is recorded between two neighboring detection target portions.

Disclosed is a method for processing a primary signal produced by a sensor detecting the rotation of a rotating target. The primary signal includes pulses having, for a given speed of rotation of the target, a first positive voltage level for rotation in a first determined direction or a second positive voltage level for the opposite direction. A first secondary signal is generated by comparing the primary signal to a first determined voltage threshold between the first and second voltages. A second secondary signal is generated by comparing the primary signal to a second determined voltage threshold between the second voltage level and zero. A determined delay is introduced in the second secondary signal. A determined time threshold is compared to the duration between an active edge of the second secondary signal and the last preceding active edge of the first secondary signal, indicating direction.

Disclosed is a method for determining the angular position of a toothed target which is rotationally secured to a shaft of an internal combustion engine. The method is based on dynamically determining a ratio between the different periods measured between the teeth of the target. Comparing the ratio with a threshold value allows identification, where appropriate, of an angular reference zone around the periphery of the toothed target.