A rotation angle measuring apparatus and method are provided for measuring a rotation angle of a moving disk relative to a stationary disk, the moving disk being configured to rotate about an axis and the stationary disk being arranged opposite the moving disk. A magnet is arranged on the moving disk. A first magnetic sensor is arranged on the stationary disk, the first magnetic sensor generating an angle signal under the action of the magnet as the moving disk rotates. An incremental rotation angle of the moving disk is determined on the basis of an output of the receiving region, a period of the static electric field is determined on the basis of an angle signal generated by the first magnetic sensor, and an absolute rotation angle of the moving disk is determined on the basis of the period of the static electric field and the incremental rotation angle.

A linear displacement measuring apparatus for determining an absolute position includes a linear rail composed of individual rail segments arranged after one another in the direction of a longitudinal axis. Each of the rail segments has a material measure which comprises at least one incremental track which extends along the longitudinal axis and has equidistantly arranged position markings. In addition to the incremental track, the material measure of one of the rail segments has an absolute track with position markings for coding a plurality of absolute positions. A scanning device can be moved along the rail segments and comprises a sensor arrangement for scanning the material measures with a first sensor, a second sensor and a third sensor. The first sensor and the second sensor are offset relative to one another in the direction of the longitudinal axis and are used to detect the position markings of the incremental track.

A position detection system for detecting a movement of a machine includes a first and a second position sensor and an evaluation device. The first position sensor is configured to detect a change in a first magnetic field generated by the movement of the machine. The second position sensor is configured to detect a change in a second magnetic field, which differs from the first magnetic field and is generated by the movement of the machine. A detection result from the second position sensor has a lower resolution of a position of an element of the machine to be determined than a detection result from the first position sensor. The evaluation device is configured to evaluate the detection result from the first position sensor and/or the detection result from the second position sensor to determine the position of the element of the machine.

A non-volatile, absolute rotation sensor employs a radial guide and spiral guide rotating with respect to each other to move a marker element continuously along the radial guide so that a distance of the marker element along the radial guide provides an indication of shaft movement over multiple turns. A sensor system senses the distance of the marker element along the radial guide to provide an electric output.

An encoder includes: a reading device that reads respective electric signals from two incremental patterns respectively having graduation array pitches different from each other; a control device that calculates a measurement value, based on the electric signals; and an output device that outputs the measurement value. The control device includes: an absolute position synthesis unit that synthesizes two electric signals to generate a synthesized absolute position; a detection unit that detects two relative positions from the two electric signals; a position calculation unit that performs an arithmetic operation between the relative positions and the synthesized absolute position to calculate a calculated absolute position; an absolute position comparison unit that compares the calculated absolute position with the synthesized absolute position; and a relative position comparison unit that compares the two relative positions with each other. The output device outputs error information, based on a comparison result output from the control device.

A power tool includes an outer housing having a drive unit support portion and a handle portion, an inner housing positioned at least partially within the handle, and a drive unit positioned in the drive unit support portion. The drive unit includes an output shaft extending at least partially through the handle portion. The power tool also includes a ball screw mechanism having a nut supported at least partially within the inner housing and a screw coupled to the nut for relative axial displacement therewith in response to relative rotation between the screw and the nut. Torque from the output shaft is applied to one of the nut and the screw to cause the relative rotation. The handle portion exerts a reaction torque on the inner housing in response to the relative rotation between the nut and screw to prevent the inner housing from rotating relative to the outer housing.

A magnetic position detection device includes two magnetic scales 1a, 1b on which N and S magnetic poles are disposed alternately, magnetism sensing element groups 2a, 2b for measuring variation in magnetic fields formed respectively by the magnetic scales 1a, 1b, and a position calculation device 3 for calculating absolute positions of magnetism sensing elements 21 on the magnetic scales 1a, 1b from output values output by the magnetism sensing elements 21, wherein a difference between the respective numbers of magnetic poles on the magnetic scales 1a, 1b is 2, and the magnetism sensing elements 21 are disposed such that arrangement intervals between the magnetism sensing elements 21 of the respective magnetism sensing element groups 2a, 2b each take a value obtained by dividing a length of one magnetic pole equally by the number of magnetism sensing elements 21.

A rotary encoder includes a rotor, a stator, and a casting compound. The casting compound has a first surface facing the stator. The first surface has a first predetermined shape and is fixed in relation to the stator. The casting compound has a second surface facing away from the stator, the second surface having a second predetermined shape.

A vernier sensor including a coarse sensor and a fine sensor may require calibration to ensure accurate position measurements. Calibration may include determining coefficients for harmonics that can be added to the coarse sensor output and the fine sensor output to reduce harmonic distortion. The disclosure describes using the offset and variance of a difference signal as the basis for calibration. This approach is possible at least because the frequencies of the coarse sensor and fine sensor can be selected to reduce the complexity of these calculations.

Encoder system (1) for a drive, including a revolution counter having a Wiegand sensor (23) which is disposed on a stationary part (13) of the encoder system (1), and at least two pairs of magnets which in the revolving direction (5) are disposed at different positions on a rotatable part (15) of the encoder system (1), wherein the pairs of magnets comprise in each case a first magnet (35) and a second magnet (37); and a position encoder having a magnetic field sensor (43) which is disposed on the stationary part (13), and a magnetic strip (47) which is disposed on the rotatable part (15); wherein, in each pair of magnets, the first magnet (35), the magnetic strip (47) of the position encoder, and the second magnet (37) in terms of a first direction are disposed in this sequence on the rotatable part (15).