JP2009128058A - Method for improving accuracy in determination of operation abnormality of rotary encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the accuracy in determination of the operation abnormality of a rotary encoder even when there is nonuniformity in an operation initial value of the rotary encoder according to individual specificity thereof. <P>SOLUTION: This method relates to the rotary encoder 11 for which an operation abnormality determination program for determining the operation abnormality when an operation state detection value changes from the operation initial value to a value (abnormality determination value) being apart at a prescribed range from the initial value, is set. In order to improve the accuracy in determination of the operation abnormality, the rotary encoder 11 is equipped with CPU 37 which executes the operation abnormality determination program and with a flash memory 39 which stores the program rewritably. At the time when the initial value (first initial value) written in this program differs from an initial value (second initial value) obtained by external measurement, the initial value to be written in the program is changed from the first initial value to the second and also the abnormality determination value is changed from the second initial value to a value being apart at a prescribed range therefrom. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary encoder in which an operation abnormality determination program for determining an operation abnormality is set when the operation state detection value fluctuates from an initial value of the operation to a value within a certain range (abnormality determination value). The present invention relates to a method for improving abnormality determination accuracy.

  For example, in an electronic control system that electronically controls an elevator apparatus, a rotary encoder is attached to a motor shaft of a drive motor that drives a car up and down, and both A and B phase signals from the rotary encoder are input to the electronic control apparatus. The electronic control device drives and controls the drive motor by both A and B phase signals from the rotary encoder to control the raising / lowering of the car (for example, see Patent Document 1).

  In this electronic control system, the safety of the electronic control system is mainly achieved by the control operation of the control CPU incorporated in the electronic control device. The control CPU controls various loads in response to control programs, various control constants, and operating states of various input sensors.

  The conventional rotary encoder used in the electronic control system has a rotation having a plurality of rotating slits that can transmit light from the light projecting element at equal intervals in the circumferential direction between the light projecting element and the two light receiving elements. A slit plate and a fixed slit plate having a fixed slit capable of transmitting light from a light projecting element on one side of the rotary slit plate in the same manner as the rotary slit are disposed opposite to each other (Patent Document 2).

  The fixed slit of the fixed slit plate shifts light from the light projecting element by 90 degrees sequentially in electrical angle and passes through the rotary slit of the rotary slit plate to form an optical signal. The light receiving element receives the optical signal, generates both A and B phase signals as pulse signals from the light receiving output of the light receiving element, and from these A and B phase signals, the rotation state of the detected shaft, that is, its rotation direction and rotation The speed can be detected.

  In the above configuration, when the rotary encoder causes a sudden abnormality while controlling the elevator motor by controlling the drive motor based on both the A and B phase signals from the rotary encoder, the electronic control device On the side, the elevator apparatus during the control operation cannot be controlled properly and safely.

  Under such circumstances, there is a demand for a system that can continue operation without being abnormal at the present time during control operation of the elevator apparatus, but can take appropriate measures before the occurrence of abnormality is predicted.

  Therefore, as an example of the above measures, in the rotary encoder, when the detection value of the operation state of each element of the light projecting element and the rotary encoder fluctuates to a value (abnormality determination value) separated from the initial operation value of each part by a certain range It is conceivable to set an operation abnormality determination program for determining that there is an abnormality. In this case, when the detected value is a value from the initial operation value to the abnormality determination value, the rotary encoder is normal. When the detected value reaches the abnormality determination value, it is determined that the rotary encoder is abnormal. On the other hand, this abnormality determination is not only normal when the operation state is classified into normal and abnormal, but it cannot be said that it is normal, but although the electronic control unit can control the controlled object with the detection output of the rotary encoder, The value to be predicted is also included in the abnormality judgment value.

For example, when the operation initial value and the abnormality determination value are incorporated in the operation abnormality determination program of the rotary encoder to be manufactured, the operation initial value varies depending on the individual difference of each rotary encoder, but is related to the individual difference. The abnormality judgment value is fixed. Therefore, for example, when the initial value of the output voltage of the light receiving element is 400 mV and the abnormality determination value is 300 mV (decreased light receiving output 25%), there is a rotary encoder whose initial operation value is 440 mV due to variations in the initial operation value. In the rotary encoder, if the light reception output does not decrease (down 33%) to the abnormality determination value of 300 mV, it is not determined that the operation is abnormal. In such operation abnormality determination, the determination of operation abnormality differs for each rotary encoder, which is a big problem in an electronic control system using a rotary encoder.
Japanese Patent Application Laid-Open No. 09-077412 Japanese Patent Laid-Open No. 07-134048

  The problem to be solved by the present invention is to improve the determination accuracy of the abnormal operation of the rotary encoder even if the initial value of operation varies depending on the individual difference of the rotary encoder.

  The method for improving the operation abnormality determination accuracy of a rotary encoder according to the present invention is an operation abnormality that is determined to be an operation abnormality when the operation state detection value fluctuates from the initial value of the operation to a value (abnormality determination value) separated by a certain range. In order to improve the determination accuracy of the operation abnormality in the rotary encoder for which the determination program is set, a CPU that executes the operation abnormality determination program in the rotary encoder, and a flash memory that stores the operation abnormality determination program in a rewritable manner. When the initial value (first initial value) written in the operation abnormality determination program is different from the initial value (second initial value) measured externally, the initial value written in the operation abnormality determination program is set to the first value. The initial value is rewritten to the second initial value, and the value is a certain range away from the second initial value. It is characterized in that rewriting the value.

  In the present invention, even if the initial value varies due to individual differences of the rotary encoder, an abnormality determination value is set corresponding to each of the dispersed initial values, so that the determination accuracy of the operation abnormality of the rotary encoder is improved. Will be able to.

  For example, when the initial value of the output voltage of the light receiving element is 400 mV and the abnormality determination value is 300 mV, the decrease in the light receiving output is 25% (100 mV). When there is a rotary encoder with an initial operation value of 440 mV due to variations in the initial operation value, the abnormality determination value is improved by setting the abnormality determination value to 330 mV (decreased light reception output by 25%). Become. Further, in a rotary encoder with an initial operation value of 360 mV, the operation abnormality determination accuracy is improved by setting the abnormality setting value to 270 mV (decrease in light reception output by 25%).

  In the present invention, not only the level reduction of the light reception output but also the operation initial value and the abnormality determination value can be set similarly for the duty of the light reception output. For example, when the duty of the initial value of operation is 50%, and 47% and 53%, which are values separated by a certain range ± 3%, are used as abnormality determination values, the initial value of operation varies due to the rotary encoder, for example, 51%. Conventionally, the abnormality determination values are fixed 47% and 53%, and the operation abnormality determination accuracy is low. In contrast, in the present invention, 48% and 54%, which are values within a certain range of ± 3% from the initial operation value of 51%, are the abnormality determination values. As a result, the abnormality determination accuracy is greatly improved as compared with the prior art.

  In the present invention, even if the initial operation value varies due to individual differences among the rotary encoders, it is possible to improve the determination accuracy of the abnormal operation of the rotary encoder.

  Hereinafter, an electronic control system for controlling an elevator apparatus according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. Referring to FIG. 1, an elevator apparatus 1 drives a hoisting machine 3 by a driving motor 5 to raise and lower a car 9 via a rope 7, while a motor shaft of the driving motor 5 that is a detected shaft. Both the A and B phase signals, which are detection signals from the rotary encoder 11 attached to 10, are input to the electronic control unit 13. The electronic control device 13 includes a control CPU (not shown) in FIG. 1, and drives and controls the drive motor 5 by a detection signal from the rotary encoder 11. There are various other control contents of the elevator apparatus 1 by the electronic control apparatus 13, but the description thereof is omitted.

  Referring to FIG. 2, the rotary encoder 11 includes an encoder housing 12 fixed to a mechanism (not shown), and is supported on the motor shaft 10 by a pair of bearings 14 in the axial direction.

  Referring to FIG. 3, the rotary encoder 11 emits light from the light projecting element 15 at equal intervals in the circumferential direction on an optical path between one light projecting element 15 and two light receiving elements 17 and 19. A fixing having a rotating slit plate 21 having a plurality of rotating slits capable of transmitting, and a fixed slit capable of transmitting light from the light projecting element 15 on one side of the rotating slit plate 21 in the same manner as the rotating slit. The slit plate 23 is disposed opposite to the slit plate 23.

  The fixed slit of the fixed slit plate 23 sequentially shifts the light from the light projecting element 15 by 90 degrees in terms of electrical angle and passes through the rotary slit of the rotary slit plate 21 to form A-phase and B-phase optical signals. At the same time, the light receiving elements 17 and 19 receive the A-phase and B-phase optical signals shifted by 90 degrees in electrical angle, and these A-phase and B-phase optical signals are composed of a plurality of pulse trains as shown in FIG. The signal is converted into a phase signal and a B phase signal.

  The rotary encoder 11 receives the rotation speed from the number of optical signals per unit time, or “0” for the combination of the A phase signal “0” and the B phase signal “0” in the binary code of both A and B phase signals. ", A phase signal" 1 ", B phase signal" 0 "in combination" 2 ", A phase signal" 1 ", B phase signal" 1 "in combination" 3 ", A phase signal" 0 ", B In the combination of the phase signal “1”, “1” is set, and the rotation direction can be determined from the change order of the binary code.

  As shown in FIG. 5, in the rotary encoder 11, the light projected from the light projecting element 15 is obtained through the fixed slit plate 23 and the rotary slit plate 21 and is received by the light receiving elements 17 and 19. 19, the A and B phase signals are generated by the signal processing circuit 20 including a comparison circuit and the like, and both the A and B phase signals are output to the electronic control unit 13. A signal, a B phase signal, and the like are input to the flash microcomputer 25. The flash microcomputer 25 controls the light projecting element 15 on and off by applying a PWM (pulse width modulation) control pulse to the base of a transistor 27 connected in series with the light projecting element 15. Then, by controlling the pulse width for turning on the light projecting element 15, the light projecting intensity of the light projecting element 15 (the amount of light projected per unit time) is controlled. In this case, as an operation initial value to be described later, the flash microcomputer 25 may set the analog value of the received light output as the operation initial value (mV), and also set the duty of both the A and B phase signals as the operation initial value (%). Also good.

  With reference to FIG. 6, the block configuration of the electronic control system of the embodiment will be described. This electronic control system includes a rotary encoder 11, an electronic control device 13, and a drive motor 5. The electronic control unit 13 inputs and outputs various signals other than those shown in FIG. 6, but the illustration is omitted in FIG. Further, the rotary encoder 11 shows only the flash microcomputer 25 in an enlarged view. The flash microcomputer 25 includes a light reception output input unit 31, a light projecting element drive unit 33, a fail safe signal output unit 35, a CPU 37, a flash memory 39, a ROM 41, and a communication interface 43. These are interconnected by an internal bus 45. The communication interface 43 is connected to the flash writer 47 and transmits / receives information necessary for rewriting the stored contents of the flash memory 39.

  In the flash microcomputer 25, the light reception output input unit 31 performs A / D conversion on the received light reception output, and the light projecting element drive unit 33 outputs a drive signal to the transistor 27. The fail safe signal output unit 35 outputs a fail safe signal to the electronic control device 13 when the rotary encoder 11 is abnormal. In response to the fail safe signal, the electronic control device 13 controls the rotation of the drive motor 5 to the safe side to ensure the safety of the electronic control system.

  The ROM 41 stores a program for the CPU 37 to execute the operation of the entire rotary encoder 11.

  The flash memory 39 stores an operation abnormality determination program for the CPU 37 to perform operation abnormality determination.

  This operation abnormality determination program is a program that determines an operation abnormality when the operation state detection value fluctuates from the initial value of the operation to a value (abnormality determination value) separated by a certain range. In this program, an operation initial value for operation abnormality determination and an abnormality determination value which is a value separated from the operation initial value by a certain range are written. This abnormality determination value can be appropriately set by the electronic control device 13 in which the rotary encoder 11 is incorporated or the like.

  When determining the operation abnormality, the CPU 37 inputs, for example, the light reception output from the light reception output input unit 31 as the operation state detection value, and the operation state detection value is written in the operation abnormality determination program stored in the flash memory 39. When it is between the operation initial value and the abnormality determination value separated from the operation initial value by a certain range, it is determined that the operation is normal, and when the operation state detection value reaches the abnormality determination value, it is determined that the operation is abnormal.

  In such an operation abnormality determination operation of the CPU 37, for example, as shown in FIG. 7A, the light reception output is 400 mV as the first operation initial value, and the abnormality determination value is 300 mV (light reception output is reduced by 25%). In this case, the value range from the first operation initial value 400 mV to the abnormality determination value 300 mV is a constant range of 100 mV. If the first operation initial value is not 400 mV but the second operation initial value 440 mV as a result of external measurement of the operation initial value, the operation initial value of the operation abnormality determination program is rewritten from 400 mV to 440 mV, and the operation abnormality determination program The abnormality determination value is also rewritten to a light reception output 25% reduction value of 330 mV.

  Then, the CPU 37 determines that the abnormality of the light reception output is an operation abnormality when the light reception output is reduced to 330 mV from the operation abnormality determination program in which the abnormality determination value is rewritten to 330 mV.

  In rewriting the operation initial value and the abnormality determination value, the user measures the operation initial value with an external measuring instrument, and when the operation initial value is 440 mV instead of 400 mV written in the operation abnormality determination program, the measurement is performed. The data having the initial operation value of 440 mV is input to the CPU 37 via the communication interface 43 by the flash writer 47. In the CPU 37, the operation initial value written in the operation abnormality determination program in the flash memory 39 is rewritten from 400 mV to 440 mV, and the abnormality determination value is rewritten from 300 mV to 330 mV. As a result, the abnormality determination accuracy is greatly improved as compared with the prior art.

  On the other hand, not only the decrease in the level of the received light output, but also the operation initial value and the abnormality determination value can be set similarly for the duties of both the A and B phase signals. For example, as shown in FIG. 7B, when the duty value of the first operation initial value is 50% and the duty values 47% and 53% separated by a constant duty range of 3% are used as abnormality determination values, the rotary encoder 11, the first operation initial value varies, for example, if the second operation initial value is 51%, conventionally, the abnormality determination value is unchanged, 47% and 53%, and the operation abnormality determination accuracy is low. On the other hand, in the present invention, 48% and 54%, which are values separated by the constant duty range ± 3% from the second operation initial value 51%, are abnormality determination values. As a result, the abnormality determination accuracy is greatly improved as compared with the prior art.

  In the embodiment described above, the rotary encoder inputs an abnormality signal to the electronic control unit when an abnormality determination is input while the car is moving up and down. Thus, in the electronic control device, the elevator car is lifted up and down to the nearest floor and stopped, and then the elevator door is controlled to open and the alarm is controlled and the elevator device management center is notified. By performing the above, workers and the like can take maintenance and other measures appropriately and promptly.

  The electronic control system according to the embodiment can be generally applied to an electronic control system including a rotary encoder, an electronic control device, and a drive motor.

FIG. 1 is a diagram showing a schematic configuration of an electronic control system according to an embodiment of the present invention. FIG. 2 is a view showing a state in which the rotary encoder is supported on the motor shaft by a bearing. FIG. 3 is a diagram showing a schematic mechanical configuration of the incremental rotary encoder. FIG. 4 is a diagram showing the relationship between the A phase and the B phase by the incremental rotary encoder. FIG. 5 is a diagram showing a schematic electrical configuration of the rotary encoder. FIG. 6 is a diagram showing a schematic block configuration of the electronic control system according to the embodiment. FIG. 7A is a diagram in the case where the operation initial value and the abnormality determination value are indicated by voltage (mV) in the operation abnormality determination, and FIG. 7B is also the operation initial value and the abnormality determination value indicated by duty (%). FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Elevator apparatus 5 Drive motor 10 Motor shaft (detected shaft)
DESCRIPTION OF SYMBOLS 11 Rotary encoder 13 Electronic control unit 15 Emitting element 17, 19 Light receiving element 21 Rotating slit board 23 Fixed slit board 25 Flash microcomputer

Claims (1)

  Abnormal operation for a rotary encoder for which an operation abnormality determination program is set to determine that an operation abnormality is detected when the operation state detection value fluctuates from the initial value of the operation to a value (abnormality determination value) separated by a certain range. In order to improve the determination accuracy, the rotary encoder is provided with a CPU that executes the operation abnormality determination program and a flash memory that stores the operation abnormality determination program in a rewritable manner, and is written in the operation abnormality determination program. When the initial value (first initial value) is different from the externally measured initial value (second initial value), the initial value written to the operation abnormality determination program is rewritten from the first initial value to the second initial value and (2) Abnormal operation of the rotary encoder, wherein the abnormality judgment value is rewritten to a value separated from the initial value by a certain range Constant accuracy improvement method.

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