The power management unit supplies first power that is continuous power to the second sensor when the power switch is on, supplies second power that is intermittent power having a voltage lower than the first power to the second sensor when the power switch is off, and outputs rotation number information representing a rotation number of the motor rotation shaft based on the second sensor signal. The power management unit includes a comparator that operates using the second power as the power source when the power switch is off and compare the second sensor signal and the reference voltage, and a counter that detects the rotation number of the motor rotation shaft by counting the output of the comparators.

A rotary transducer is described. The rotary transducer includes a Hall effect sensor, a rotary dial comprising at least two recessed pockets, a first magnet that is positioned within one of the at least two recessed pockets, and a second magnet that is positioned within another one of the at least two recessed pockets. In an acceleration only mode, the rotary dial is rotatable from a center position in a first direction and is not rotatable from the center position in a second direction. This mode is selected when a mode selection screw is inserted into a mode selection orifice. In a bi-directional acceleration/deceleration mode, the rotary dial is rotatable from the center position in the first direction and is rotatable from the center position in the second direction. This mode is selected when the mode selection screw is not inserted into the mode selection orifice.

An encoder includes: an optical module that detects angular position information indicating an angular position of a rotating disk within one rotation thereof; a magnetic detecting unit that detects multi-rotation information indicating the number of rotations of the disk; a battery that supplies a power to the magnetic detecting unit when an external power is not supplied to the encoder; and a connector that connects connection terminals of the battery to a substrate to which at least one of the optical module and the magnetic detecting unit is connected, via solders in contact with the connection terminals.

The present disclosure provides magnetic sensor system that includes a magnet mounted on the end of a rotating shaft, a magnetic sensing device comprising a magnetic multi-turn sensor, and a mechanism for initializing the magnetic multi-turn sensor into a known state ready for use. Whilst the magnetic sensing device is being used to monitor the rotation of the shaft, the magnet is located in a starting position a first distance from the magnet sensing device such that the magnet field strength experienced by the magnet sensing device is within the operating window of the magnet multi-turn sensor, the operating window being defined by a minimum magnetic flux density, Bmin, and a maximum magnetic flux density, Bmax. The mechanism comprises a means for moving the magnet and the shaft in an axial direction towards the magnet sensing device such that the magnetic field experienced by the magnet sensing device exceeds the upper limit, Bmax, of the operating window. This causes domain wall nucleation, whereby the sensor spiral is filled with domain walls that magnetise all of the magnetoresistive elements into the same state. Once the initialization has taken place, the mechanism is configured to return the magnet to its starting position ready for use. In this respect, the mechanism may have a biasing means such as a spring that biases the magnet towards the starting position.

The influence of a leakage magnetic flux from a magnet on a magnetic sensor configured to detect a magnetic flux from the permanent magnet is reduced. An absolute encoder includes a first magnet provided at a leading end side of a first worm gear part, a first angle sensor configured to detect a rotation angle of the first worm gear part corresponding to a change in a magnetic flux generated from the first magnet, a second magnet provided at a leading end side of a second worm wheel part, a second angle sensor configured to detect a rotation angle of the second worm wheel part corresponding to a change in a magnetic flux generated from the second magnet, and a gear base part configured to surround at least a part of a periphery of the first angle sensor and the second angle sensor.

A device includes a bevel pinion meshed to a bevel ring in rigid fixation with a pinion gear engaged with a slew ring to control rotation of the slew ring. A rotation sensor provides an electrical output corresponding to a rotational position of an input gear of the rotation sensor. A reduction gearing system interposes the bevel ring and the input gear of the rotation sensor. The gearing reduction system provides a reduction ratio enabling the rotation sensor to determine rotational position of the slew ring.

At a time that a position detecting device is initiated, an arithmetic processing unit calculates the absolute position of a rotating shaft at the time of initiation, on the basis of first to third analog signals corresponding to first to third angles of rotation, which are detected respectively by first to third rotational angle detectors. During rotation of the rotating shaft, a current position counter detects a current absolute position of the rotating shaft by counting a number of pulses of forward rotation pulses or reverse rotation pulses, corresponding to the first angle of rotation detected by the first rotational angle detector, taking as a standard a total number of pulses corresponding to the absolute position of the rotating shaft at the time of initiation.

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.

A nonvolatile, absolute multi-turn rotation sensor employs a magnetic particle that is indexed around a serpentine channel with successive passes of a magnet caused by rotation of the rotation sensor shaft. Sensors at regular locations around the track allow determination of the position of the magnetic particle and thus the total number of revolutions of the shaft.

An exemplary encoder assembly includes a substrate, a first encoder, and a second encoder. The substrate has two or more position sensors, each position sensor being configured for detecting a rotary position of a shaft or other rotating element of a machine. The first encoder includes at least one first position sensor of the two or more position sensors. The at least one first position sensor is disposed on the substrate for off-axis alignment with the shaft or other rotating element of the machine. The second encoder includes a second position sensor of the two or more position sensors, the second position sensor being disposed on the substrate for on-axis or off-axis alignment with the shaft or other rotating element of the machine. Each position sensor is configured to detect different or common signal types, and a signal type of the second position sensor excludes optical signals.