Abstract: An encoder having a code carrier, light source, and detector is disclosed. The code carrier includes a track that emits light at each of a plurality of track points on the track when that track point is illuminated with light having a predetermined spectrum. Each of the track points emits light having a spectrum that is different from the spectrum emitted by others of the track points. The light source illuminates a portion of the track with light of the predetermined illumination spectrum. The detector provides a plurality of signals indicative of the spectrum of light leaving the portion of the track when the portion includes one of the track points. The code carrier moves with respect to the detector, and the signals define the relative position of the code carrier with respect to the detector.

Abstract: An encoder failure detector system and method for detecting failure of an encoder during time periods when a zero rotational speed is expected. For example, in one embodiment a test signal is applied during a period when a zero rotational speed is expected and a failure is indicated if no movement of a rotor is detected in response to the test signal.

Abstract: A displacement measuring device including a scale, and an optical readhead including an index pattern and a light receiving element is provided. A bright/dark pattern arising from a scale grating is detected by the readhead to measure displacement. In various embodiments, a magnification of the pattern is adjusted by the spacing between at least a lens element, aperture element, and detection plane of the readhead. An aperture can be designed to provide a diffraction-limited telecentric imaging configuration that filters an image of the scale grating to provide a sinusoidal intensity pattern that supports highly interpolated measurements. An aperture dimension, selected in relation to the grating pitch and other parameters, can provide a desirable combination of readhead operating characteristics including one or more of a desired depth of field; degree of spatial filtering; and optical signal power.

Abstract: An absolute linear encoder includes a plurality of absolute scales aligned in the detection direction with absolute calibrations, a plurality of detectors for detecting the calibrations on the absolute scales, absolute position data generating portions of each scale for generating absolute position data of each detector, and a calculator for outputting an absolute position over the whole length of connected whole absolute scales adding the absolute position data of each detector and the distance between the detectors. The detectors are fixed at such intervals as to simultaneously detect the calibrations of the two absolute scales adjoining in a scale connecting section. Thus, the long absolute linear encoder which is easy to use is realized at low costs.

Abstract: An optical encoder. The optical encoder includes a coding element, an emitter, and a detector. The coding element has a track with a track pattern. The track pattern includes a plurality of optically distinguishable sections. The plurality of optically distinguishable sections includes a limit switch section. The emitter generates a light signal incident on the track of the coding element. The detector includes a limit switch photodetector positioned to detect the light signal from the emitter. The detector generates a limit switch output signal in response to the detected light signal above a limit switch threshold at the limit switch photodetector. Embodiments of this type of optical encoder implement limit switches into a single track on the coding element.

Abstract: To provide encoder count error detection circuitry and an encoder count error detection method capable of realizing a highly reliable encoder by providing detection of the count errors of count signals used to measure displacement, an encoder count error detection circuitry and detection method configured as count error detection circuitry for an encoder outputting pulse trains according to the displacement of a measured object, doubles, triples, or quadruples one or more fundamental signals used for measuring displacement to convert to count signals, and compares the output signals of the counter counting these count signals with the level of these fundamental signals to detect count errors in the count signals.

Abstract: A method for determining the absolute value of a rotational angle includes imaging a continuous segment of a code track of a code carrier on a sensor array such that the sensor array generates a corresponding output signal. The code track has a light and dark transition pattern over an angular range of 360°. The sensor array output signal is subjected to a convolution operation with a reference signal in a first correlation filter to reconstruct the light and dark transition pattern of the imaged segment of the code track as a first correlation function signal. The first correlation function signal is processed to determine a code word and a predetermined angle corresponding to the code word.

Abstract: An encoder failure detector system and method for detecting failure of an encoder during time periods when a zero rotational speed is expected. For example, in one embodiment a test signal is applied during a period when a zero rotational speed is expected and a failure is indicated if no movement of a rotor is detected in response to the test signal.

Abstract: An optical encoder includes a cylindrical reflective scale, a point light source for irradiating the reflective scale, and light-receiving elements for receiving the light beams reflected by the reflective scale. The pitch of the reflective scale is set to an appropriate value such that the pitch of interference fringes formed by light beams that are reflected by the reflective scale is matched to the pitch of the light-receiving elements at a position with a desired gap.

Abstract: Various apparatus and methods of a multi-mode encoder output generator are disclosed.

Abstract: A rotary switch including a control element, a light-emitting device arranged on a printed circuit board and configured to emit light, and at least two receivers arranged on the printed circuit board in correspondence with the light-emitting device and configured to detect switching positions of the rotary switch. Further, the light-emitting device is mounted radially at an outside portion of inside of a hollow cylindrical extension of the control element, and wherein on level with the light-emitting device, the extension includes orifices evenly distributed around a periphery of the extension, and that opposite the light-emitting device, on an exterior side of the extension, the at least two receivers are arranged.

Abstract: An optical encoder includes a mobile object having a plurality of aligned slits, a light-emitting portion for emitting light toward the mobile object, and a light-receiving portion 103 for receiving the light which has passed the mobile object. The light-receiving portion 103 produces an AC (Alternating Current) signal in an oscillation circuit 111 and outputs an input current, which is changed to an AC, from a light-emitting current output circuit 112 into the light-emitting portion.

Abstract: An encoder having a code scale and an emitter detector module is disclosed. The code scale includes alternating reflective and opaque stripes. The emitter-detector module includes a light source that generates light and directs a portion of the generated light to the imaging element and a photodetector that generates a signal representing an intensity of light having a linear polarization in a predetermined direction received by the photodetector, the light source and the photodetector are encapsulated in a transparent medium, wherein there is a gap between the transparent medium and the code scale. The predetermined direction is chosen to reduce the intensity of light received by the photodetector that is reflected from an interface between the transparent medium and the gap. A polarization filter can also be included in the light source to further improve the rejection of the light reflected from the interface of the transparent medium and the gap.

Abstract: A novel encoder system adapted for use in print architecture at least includes: a codewheel coupled to a rotating print architecture element; a first encoder sensor mounted at a first position relative to the periphery of the codewheel, the first encoder adapted to output a first output signal; a second sensor mounted at a second position relative to the periphery of the codewheel, the second encoder adapted to output a second output signal, and the second sensor positioned substantially 180 degrees relative to the first encoder sensor; and a logic correction circuit adapted to receive the first and second output signals, and for outputting a correction signal with a period that is the average of the periods of the first and second output signals.

Abstract: An encoder device for the determination of absolute angle or linear segments is described, with which the distance from the actual to the reference position is determined upon prompting and output via incremental signals. This encoder offers new functions for the incremental measuring system employed up to now. The transition to the absolute measuring system is also made possible according to requirements.

Abstract: A coding element such as a codewheel includes first and second surfaces that are configured with respect to each other and with respect to a light beam such that the light beam is reflected at the two surfaces using the optical phenomenon of total internal reflection. The coding element also includes a coding pattern that is aligned in an optical path of the light beam after the light beam has reflected off of both of the surfaces. A coding element with surfaces that reflect a light beam as a result of total internal reflection can be utilized in an encoding system that operates in transmission while the light source and the photodetector array are located on the same side of the coding element.

Abstract: An encoding system for determining position and position changes of a moving member has a sequence of encoder marks forming incremental patterns and at least one index pattern. Two subsequent incremental patterns are indicative of an incremental position-change of the moving member and the index pattern is indicative of a reference position of the moving member. A sensor arrangement views a section of the encoder-mark sequence, the length of which is greater than one position-change increment. An analyzer is arranged to analyze an encoder-mark pattern in the viewed section with regard to the incremental patterns and the index pattern and to generate, in response to a pattern match found, at least one of an incremental-position-change signal and an index signal.

Abstract: A mechanical weighing scale having mechanical parts driving a pointer rotating around a fixed disc or dial having slots or holes formed therein. The mechanical pointer operates to provide an analog display of one's weight to the user. An optical sensor system is responsive to the mechanical motion of the mechanically-rotating pointer as it passes over each of the holes or slots for determining a number of counts associated with the mechanical motion of the rotating pointer and translating the counts to a corresponding weight value for display onto a digital display.

Abstract: A Resolver/Digital (R/D) converter includes an encoder output divider having a DSP generating 14-bit encoded signals A2 and B2 from a timing analysis performed during the first period of 12-bit encoded signal A1. The DSP generates a selection signal output to a multiplexer to select encoded signals A1 and BE1 or encoded signals A2 and B2 depending on the rotational speed of the rotor of a resolver. Based on the selection signal, the multiplexer outputs 12-bit encoded signals A1 and B1 when the rotational speed is less than 400 rpm or greater than 1200 rpm, and outputs 14-bit encoded signals A2 and B2 when rotational speed is between 400 rpm and 1200 rpm.

Abstract: An encoder system includes an encoding medium having a plurality of encoder target portions alternating with a plurality of encoder window portions. A sensor is movable in relation to the encoding medium. A signal source provides an electronic drive signal to the sensor and sensor electronics coupled to the sensor sense an electrical characteristic of the code strip to determine whether the sensor is next to an encoder target portion or is next to an encoder window portion.

Abstract: A multicolor-printer has a plurality of print stations arranged to generate an image on a recording medium, and a recording medium conveyor. A plurality of similar encoding marks are associated with the conveyor. Sensor arrangements are associated with the print stations, responsive to the encoding marks. They generate signals indicating the conveyor movement with respect to the corresponding print station. An index marking is indicative of a conveyor reference position. The sensor arrangements are responsive to it, thereby providing information about the reference position with respect to the corresponding print station. The printer registers images of different print stations with each other based on the movement and reference-position information.

Abstract: A digital incremental encoder for generating an output signal indicative of an angular position, a direction of rotation, and a speed of rotation of a shaft. A counter receives a PWM signal indicative of the angular position of the shaft and a clock signal from an angular position sensor, and generates a multi-bit output. A latch latches the multi-bit output, a first bit and a second bit of which are used to generate the output signals that include the first bit. The first bit and the second bit may be XOR'd together to generate an XOR output included in the output signals. A direction of rotation may be derived from a quadrature phase relationship between the first bit and the XOR output. The angular position sensor may be an NCAPS or MT-NCAPS. A linear position sensor may be used instead of an angular position sensor to generate the PWM signal.

Abstract: A rotation position detecting device includes an angular signal generator which generates pulses the cycle period of which is even or equal when a rotating object rotates at a constant rotation speed and a non-pulse portion which corresponds to a reference position, an up-down command circuit for generating an up-down command signal the frequency of which is divided to a half of the frequency of the angular signal, a pair of first counters for counting up or down the clock signal when the up-down command signal changes from a first level to a second level to reset and subsequently counting down the clock signal when the up-down command signal changes from the second level to the first level, a pair of processing circuits for providing a first and second reference values, a pair of counters which generates detection signals when the counted number of the counters becomes smaller than the first or the second reference value.

Abstract: An encoder includes comparators CP4 and CP5 which are provided in such a manner as to correspond to phase A and B respectively and detect a state where the output voltages deviate from their normal ranges. Transistors TR4 and TR5 which operate according to the outputs of the respective corresponding comparators are connected through resistors R8 and R18, respectively, to an output line of phase Z. When each output line connecting to a phase-A output terminal QA or a phase-B output terminal QB is short-circuited to ground, or a signal line 41A or 42B connecting the output terminal with a electronic control unit 40 is broken, the transistor TR4 or TR5 is turned on and the output of phase Z falls below its normal range, thereby a malfunction is detected. Even if one of the transistors of phase A and phase B breaks down, a malfunction in the other phase is transmitted to phase.

Abstract: An encoder interface device that permits automatic discovery of an unknown encoder that is physically connected to the interface device, so as to enable correct operation. The device permits discovery of characteristics of an unknown encoder including the primary quadrature A and B channels, the index channel, and the active state of the index channel. Once discovered and configured, the device indicates the index position of the encoder with an accuracy of a single encoder count. The device also supports “wide” index pulses, in which the index channel is active for more than seven consecutive encoder counts. The device also provides for the discovery, configuration, and position latching with single-encoder-count accuracy for encoders having index pulses of almost arbitrary width.

Abstract: After cyclic original signals generated from a sensing element of an encoder are converted into digital signals, positions P(0) to P(n) in one period are obtained for each given period by means of a digital interpolator. If position data obtained immediately after a zero cross point is detected are P(0) and P(n) and if speed is fixed, an object should move on a straight line from a position P(0) to a position P(n). An actual detected position data P(m) is deviated from this straight line by D(m). This detection error D(m) and the detected position data P(m) are combined and stored in advance as reference data, and correction is carried out using the reference data every time position data is detected by the digital interpolator.

Abstract: A scale generates a periodic light-intensity distribution pattern having a pitch upon irradiation by emission light from a light source. Light-detecting element groups are shifted relative to the scale to generate phase signals having fixed phase differences. Light-detecting elements are adjacently positioned to have the same phase to form each light-detecting element group. Area centers of gravity on a phase axis of the light-detecting element groups having a fixed phase difference are made coincident with each other.

Abstract: An assembly for optoelectronically sensing position includes a light source, a coded element, and a plurality of photosensors. Holes are disposed in the coded element to define a plurality of digital codes. The light passes through the holes in the coded element to illuminate the photosensors. The holes are sized and the photosensors are positioned such that the light is transmitted to more than one of the photosensors through each of the holes.

Abstract: A method for detecting an absolute rotational position of an electromechanical device or the at least one component thereof comprising determining a first absolute position of the electromechanical device or the at least one component thereof based on a commutation index signal, obtaining a Z-index signal, and determining a second absolute position of the electromechanical device or the at least one component thereof based on the Z-index signal. The method initially determines a coarse rotational position of the electromechanical device such as a rotor or steering wheel based on the commutation index signal. When a device's position is first initialized by a commutation index signal before the Z-index pulse is detected, the device's position is re-initialized upon detection of the Z-Index pulse to provide a more accurate absolute device rotational position.

Abstract: A device for position indication and the detection of guidance errors that includes a scale that has a position measuring graduation arranged in a position measurement direction. A first guidance error measuring graduation which is arranged perpendicularly with respect to the position measurement graduation and a second guidance error measuring graduation which is arranged perpendicularly with respect to the position measurement graduation, wherein the first guidance error measuring graduation and the second guidance error measuring graduation are arranged on both sides of and adjacent to the position measuring graduation. A position indication scanning unit movable with respect to the scale, wherein the position indication scanning unit scans the position measuring graduation for generating position measurement signals.

Abstract: An ink jet printer has a line head having heating elements (121d) for ejecting ink droplets from nozzles, in which the plurality of heating elements (121d) are arrayed in a direction substantially perpendicular to the paper feed direction. In the line head, the plurality of heating elements (121d) are divided into a plurality of blocks, with each block consisting of a predetermined number of spatially arrayed heating elements of the plurality of heating elements (121d) corresponding to the plurality of nozzles, and a phase signal PH is sequentially supplied to a set of heating elements (121d) simultaneously driven over the respective blocks, thus sequentially driving the respective heating elements (121d) by each set as a unit in a time-divisional manner. Thus, the ink jet printer can reduce the positional shift of dots on the paper and can reduce the instantaneous maximum dissipation power in time-division drive.

Abstract: A method for providing robust and reliable transmission of shaft encoder signals. Initially, the differentially encoded shaft encoder signals are received. The shaft encoder signals are converted into single-ended electrical signals. These single-ended electrical signals are then converted into optical signals. Finally, the optical signals are transmitted through optical conductors.

Abstract: A timing device, such as a timing disk or a timing ruler is provided with a carrier having at least one code track of a group and overlapping therewith and at least one code marking, which is scanned by a sensor unit to produce signals. The code track or tracks have a different optical density in comparison to the first group, and the code markings within a code track overlap. Also disclosed is a positioning device which includes a timing disk or a timing ruler with a carrier having a first group of code markings in at least one code track. Here the code markings are scanned by at least one sensor unit for producing a signal and the signal processing device for converting the sensor signal into a control signal is connected after the sensor unit.

Abstract: The invention relates to a method for automatically generating several electrical pulses using numeric default values, in particular for simulating an incremental encoder for a sequential, digital counting of linear or angular displacement values using said pulses. The method incorporates a value generator that outputs the default values repeatedly within each first cycle time, calculation and control means that detect the default values in a cyclic manner and a pulse switching interface that has one or more outputs for the pulses.

Abstract: A conversion device converts linear displacement signals from a displacement detector into non-linearly adjusted displacement signals for supply to a target such as a computer cursor controller. The displacement signals from the displacement detector are incremented, decremented, or left unchanged depending on displacement speeds detected by the conversion circuit.

Abstract: A position detection apparatus including a detection unit for an absolute track including a plural number of ABS heads for absolute track, in which the separation between neighboring heads is broadened. The n ABS heads 10-1 to 10-n are arrayed to satisfy the following equations 1 and 2 when n is an even number and the following equations 1 and 3 when n is an odd number: &lgr;1=m&lgr;, m being an integer not less than 2  (1) &lgr;1≠k(2n/2+1)&lgr;, k being a natural number  (2) &lgr;1≠k(2n+1)&lgr;  (3). By arraying the ABS heads 10-1 to 10-n under these conditions, the separation between neighboring ones of the ABS heads 10-1 to 10-n can be 2&lgr; or larger.

Abstract: A high-resolution position sensor device for use in precise positioning of servomechanisms, by providing increased resolution using of an encoder mounted on the shaft of a motor, which produces transition pulses through a light-sensitive arrangement using a photodetector. Each time the pulse makes a transition because the groove of the encoder wheel has passed, a reset signal is produced which resets to zero the number of clock pulses which have been measured for that interval between the transition pulses. The transition pulses and the time between them changes with changes in motor speed, while the system clock pulse rate remains fixed. The invention provides a more accurate position sensor, which operates by generating more transition pulses than the encoder itself actually generates. If the encoder produces transition pulses at a given resolution, the sensor device produces output pulses having a higher resolution.

Abstract: A technique that uses component data, such as servo encoder feedback data, and calculates real time histograms on a production printed wire board assembly (PWBA). If the histograms are uploaded to a main controller at specific intervals during run, aberrant servo activity can be tracked over a period of time. This could lead to finding machine problems before they become serious enough to cause shutdowns.

Abstract: A displacement measurement system and a sheet feed system incorporating the same are described. The displacement measurement system includes a support arm, a roller, and an optical encoder. The support arm has a first end and a second end and is configured to turn about a pivot axis on a pivot located closer to the first end than the second end so that displacement of the first end causes a greater corresponding displacement of the second end. The roller is mounted at the first end of the support arm and is configured to rotate about a roller axis substantially parallel to the pivot axis. The optical encoder has at least one component mounted at the second end of the support arm and is configured to generate signals responsive to movement of the second end of the support arm.

Abstract: A method and an apparatus to control the rotation of an object. In the method, first and second actual control variables which vary as the object rotates are measured. It is determined whether the first actual control variable is smaller than a predetermined control variable. It is determined whether a period of time has elapsed if it is determined that the first actual control variable is smaller than the predetermined control variable. A difference between a physical quantity that is generated corresponding to the first actual control variable and the second actual control variable is obtained, and a control amount to control the object is determined by using the difference, if it is determined that the predetermined period of time has elapsed or the first actual control variable is larger than the predetermined control variable. Here, the predetermined control variable corresponds to a position to which the object should be rotated to stop the object at a desired position.

Abstract: A position detection apparatus including a detection unit for an absolute track including a plural number of ABS heads for absolute track, in which the separation between neighboring heads is broadened.

Abstract: There is provided a position transducer (1) capable of accurately detecting an n-bit code by n ABS detectors from one ABS track. When an INC value is under j or over k, signal output from each of the ABS detectors is binarized based on a threshold h and also based on a threshold l. First, an ABS value decider (24) decides that a bit is “H” when it has been judged as being “H” on the basis of both the thresholds and a bit is “L” when it is has been judged as being “L” on the basis of both the thresholds. When the INC value is under j, a lower bit has the same code as that of the deiced bit. So, the ABS value decider (24) decides that the lower bit is “H” or “L”. On the other hand, when the INC value is over k, an upper bit has the same code as the decided code. Thus, the ABS value decider (24) decides that the upper bit is “H” or “L”.

Abstract: An encoder that includes a sensing device that senses encoding marks on a sensing surface that also includes one or more reference marks. The sensing device generates first and second encoder signals when the encoding marks pass the sensing device. The encoding signals define the direction of motion and degree of movement of the sensing surface. A register stores the position of the encoding surface relative to the sensing device. A controller receives the first and second encoder signals and increments or decrements the digital register based on the received first and second encoder signals. The encoder also includes a reference mark detector that generates a first reference mark signal when the first reference mark passes the reference mark detector. The controller resets the digital value to a first reference value when the encoder receives the first reference mark signal.

Abstract: A high-resolution position sensor device for use in precise positioning of servomechanisms, by providing increased resolution using of an encoder mounted on the shaft of a motor, which produces transition pulses through a light-sensitive arrangement using a photodetector. Each time the pulse makes a transition because the groove of the encoder wheel has passed, a reset signal is produced which resets to zero the number of clock pulses which have been measured for that interval between the transition pulses. The transition pulses and the time between them changes with changes in motor speed, while the system clock pulse rate remains fixed. The invention provides a more accurate position sensor, which operates by generating more transition pulses than the encoder itself actually generates. If the encoder produces transition pulses at a given resolution, the sensor device produces output pulses having a higher resolution.

Abstract: The invention makes secure the processing of a signal (Se) delivered by a sensor (2) of resistive analog type, in a safety device, the signal (Se) being converted into a digital signal (n) in an analog/digital converter (4) of resolution (R). A digital signal (n1) is acquired and stored, then the supply voltages (Va, Vb) of the sensor (2) are inverted (at 8) and a new digital signal (n2) is acquired. The two signals (n1, n2) are summed, and their sum (S) is compared with the resolution (R) of the converter (4). Depending on whether the sum (S) is or is not equal to the resolution (R), the control (Cm) of an actuator (6), corresponding to a pre-set (Sc), is enabled or otherwise. Application to tower crane safety devices.

Abstract: A sensor system is provided in which a digital absolute value of the particular position of a stationary part (stator) with respect to a part moving relative to it (rotor) is created, which is transferred in serial transmission to an evaluation circuitry, whereby transfer of the serial absolute value is induced each time by an external signal. In order to increase the resolution of the encoder, the change in absolute value is recorded each time in the sensor and finest interpolation is undertaken beginning each time from the time of the change. Finally, the absolute value is amended by the accumulated result of finest interpolation when interrogated by the external signal.

Abstract: A method for evaluating a signal generated by a position measuring system having an encoder with a code track. The encoder is interposed between a light source and a light sensor and moves relative to the light source and the sensor such that the code track transmits light from the light source onto the sensor. The light sensor generates the signal as a function of the light received by transducers of the sensor. The method includes determining brightness of a code track signal generated by sensor transducers assigned to a code track of the encoder and determining brightness of a non-code track signal generated by sensor transducers assigned to a non-code track of the encoder. The sensor transducers assigned to the code track of the encoder are then determined as being exposed to the light source as a function of the relative brightness between the code and non-code track signals.

Abstract: An incremental rotary encoder includes a rotary portion, a first sensor and a second sensor, the first and second sensors being arranged so as to be opposite from each other with respect to the axis of the rotary portion. The second sensor is offset from the first sensor so that the phase of output voltage of the second sensor advances or delays with respect to the phase of output voltage of the first sensor by &pgr;/X, wherein “X” represents a real number of one or more than one.

Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.

Abstract: A multi-turn rotary encoder that includes a first code carrier connected with an input shaft, a scanning device that scans the first code carrier and generates an absolute position of the input shaft within one revolution, and a digital code word is present at an output of the scanning device and a second code carrier for measuring the number of revolutions of the input shaft. A reduction gear is arranged between and coupled to the first and second code carriers. The second code carrier includes a magnetic body with at least one north and south pole and a substrate with a spatial arrangement of sensor elements integrated therein, which are sensitive to magnetic fields, is associated with the magnetic body.