JP5043638B2 - Rotary encoder - Google Patents

Description

  The present invention relates to an absolute type or incremental type rotary encoder, and more particularly to a rotary encoder capable of monitoring the state of the rotary encoder and transmitting the monitoring result to a host device of the rotary encoder.

  For example, an incremental type rotary encoder RE will be described with reference to FIG. 8 and subsequent drawings. FIG. 8 shows a mechanical configuration of the rotary encoder RE, FIG. 9 shows an electrical configuration of the rotary encoder RE, and FIG. The waveform of a phase signal and a B phase signal is shown.

  Referring to FIG. 8, the rotary encoder RE includes light from the light projecting element LED at equal intervals in the circumferential direction between the light projecting element LED and a plurality (two in this example) of light receiving elements PDa and PDb. A rotary slit plate RS having a plurality of slits (hereinafter referred to as “rotary slits”), and light from the light projecting element LED can be transmitted to one side of the rotary slit plate RS in the same manner as the slits. A fixed slit plate FS having a slit (hereinafter referred to as “fixed slit”) that can be formed is disposed oppositely.

  The fixed slit of the fixed slit plate FS shifts the light from the light projecting element LED by 90 degrees sequentially in electrical angle and passes through the rotary slit of the rotary slit plate RS to form an optical signal. The optical signals are received as the detection circuit 105 by the light receiving elements PDa and PDb.

  Referring to FIG. 9, the outputs of the light receiving elements PDa and PDb are compared with the reference value (ref) by the A-phase and B-phase determination circuits 106 and 108 including the comparators CPa and CPb, respectively. A-phase and B-phase signals (pulse signals) as shown in (b) are generated, and the A-phase and B-phase signals are output from the A-phase and B-phase output circuits 107 and 109, respectively. .

  When the rotary encoder RE having the above configuration is incorporated into, for example, an electronic control system that electronically controls an elevator, the rotary encoder RE is attached to the rotary shaft of a drive motor that drives the car to move up and down, and the rotary encoder RE The A-phase and B-phase signals are input to the electronic control device that is the host device. The electronic control device drives and controls the drive motor by the A-phase and B-phase signals from the rotary encoder RE 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.

  In the above configuration, it is conceivable that the electronic control device side additionally includes a determination program for performing a fixed determination on the abnormal state on the rotary encoder RE side based on the presence / absence of the A-phase and B-phase signals, the signal waveform, and the like. However, the additional installation of such a determination program and the execution of the determination program increase the burden on the control CPU and cause a delay in electronic control speed and an increase in cost. Moreover, it is difficult for the elevator manufacturing side and the encoder manufacturing side to be separated, and for the elevator manufacturing side to add the determination program or the like unless the details of the rotary encoder RE are clear. Moreover, in an elevator apparatus that has already been installed in a building or the like, in most cases, it may be left unattended.

  Under such circumstances, the rotary encoder RE side constantly monitors its state so that the rotary encoder RE does not suddenly become abnormal, and immediately notifies the monitoring state to the electronic control unit, which is the host device. It is desirable that the electronic control device can perform the required response quickly.

  Accordingly, the applicant of the present invention incorporates a monitoring CPU in the rotary encoder RE, and assumes a number of items for monitoring the state of the rotary encoder RE, and causes the monitoring CPU to capture monitoring signals for each item. It is considered that the processing result of the rotary encoder RE monitoring is transmitted to the host device by the CPU.

  The above monitoring items include the state of the main power supply, the state of the light emitting element, the state of the light receiving element, the state of the internal circuit such as the output circuit of the A phase and B phase signals, and the A phase and B phase signals that are external outputs. There are many pulse signal states. In this case, the monitoring CPU attempts to monitor the internal circuit abnormality at the internal interrupt timing, and to monitor the pulse signal abnormality at the external interrupt timing (pulse signal change timing). In the case of high-speed rotation, the internal interrupt is affected by the priority of the external interrupt, and the monitoring error becomes large, which affects the safety and stability of the entire electronic control system incorporating the rotary encoder RE. Will come.

  Therefore, in order to fully utilize the control capability of the monitoring CPU, the applicant of the present invention monitors the monitoring items of the monitoring CPU while the rotation is stopped, and monitors the abnormality of the internal circuit, and the rotation of the pulse signal is abnormal during the rotation operation. It is considered to divide the monitoring items according to the rotation state, such as monitoring.

On the other hand, in the case of a rotary encoder, in order to avoid the burden on the monitoring CPU, among the above-described pulse signals such as the A phase signal and the B phase signal, for example, the A phase signal is used for rotational speed detection. Will not change in rising or falling due to some abnormality, and if it is fixed at high level or fixed at low level, external interrupts will not occur due to changes in rising or falling of B phase signal, and abnormality detection of the B phase signal will be detected become unable.
Japanese Patent Application Laid-Open No. 09-077412

  Therefore, in the present invention, when a monitoring CPU is mounted on the rotary encoder and the state of the rotary encoder is monitored, the burden on the monitoring CPU can be reduced, so that the safety of the entire electronic control system described above can be reduced. Improvement of stability and stability is a problem to be solved.

A rotary encoder according to the present invention includes a light projecting element, a plurality of light receiving elements disposed opposite to the light projecting element, and a plurality of circumferential directions that are disposed between the light projecting element and the light receiving element and rotate synchronously with a detected shaft. A rotary slit and at least two pulse signals having a 90-degree phase difference used to detect the rotational state of the rotary encoder from the output of each light receiving element according to the passage and blocking of the light projection from the light projecting element to the rotary slit An output circuit for generating and outputting (A-phase and B-phase signals), and a monitoring CPU for monitoring the internal state of the rotary encoder with different monitoring items during rotation stoppage and during rotation operation,
The monitoring CPU determines whether the rotary encoder is non-rotating or rotating based on one pulse signal (A-phase signal) of at least two pulse signals. When the monitoring item is monitored and the rotation is determined, if the phase difference between at least two pulse signals (A phase, B phase signal) is equal to or greater than a predetermined value, a process of outputting a fail output to the host device is performed. If the phase difference is less than a predetermined value, the subsequent pulse signal calculation process is performed, and if the calculated result is out of the predetermined range, a fail output is output to the host device. Is.

  In this case, it is preferable that the monitoring CPU determines the rotation or non-rotation of the rotary encoder from the period calculation of one pulse signal (A phase signal) of at least two pulse signals.

  In the present invention, a monitoring CPU for monitoring the state of the rotary encoder is built in, and the monitoring CPU monitors the internal state of the rotary encoder using different monitoring items when the rotation is stopped and during the rotation operation. As a result, the processing load on the monitoring CPU during the rotation operation can be greatly reduced. As a result, the state of the rotary encoder is immediately transmitted to the electronic control device, which is the host device, so that the required response can be quickly performed on the electronic control device side. As a result, it is possible to improve the safety and stability of the entire electronic control system incorporating the rotary encoder.

  In the present invention, one of the pulse signals (A phase signal) is used for rotational speed detection, and when the non-rotation state is determined from the period calculation of the A phase signal, the monitoring item at the time of rotation stop is monitored. Therefore, the monitoring CPU can accurately determine whether the rotary encoder is stopped or rotating, and can perform monitoring processing on a required monitoring item while the rotation is stopped.

  Further, in the present invention, after determining the rotation state, if the phase difference between the A-phase and B-phase signals is equal to or larger than a predetermined value, a process of outputting a fail output to the host device is performed, and the phase difference is less than the predetermined value. If there is, the subsequent pulse signal calculation process is performed, and if this calculation result is outside the predetermined range, the process of outputting the fail output to the host device is performed. Even if the pulse signal (B phase) other than the detection signal (A phase) does not change in rising or falling due to any abnormality, even if it is fixed at high level or fixed at low level, it detects the abnormality of the corresponding pulse signal, Can be transmitted to the host device.

  As described above, according to the present invention, the state of the rotary encoder can be immediately transmitted to the electronic control device, which is the host device, so that the required response can be quickly performed on the electronic control device side, and the rotary encoder is incorporated. This contributes to improving the safety and stability of the entire electronic control system.

  In the present invention, when the monitoring CPU is mounted on the rotary encoder and the state of the rotary encoder is monitored, the burden on the monitoring CPU can be reduced, so that the safety and stability of the entire electronic control system described above can be reduced. It is possible to improve the performance.

  Hereinafter, a rotary encoder according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a circuit block configuration of the rotary encoder RE of the embodiment, and FIG. 2 shows an electrical hardware configuration of the rotary encoder RE. In these drawings, reference numeral 101 denotes a power supply circuit that receives supply of power from the external terminals Vcc and 0 V and generates the internal power supply 104 of the rotary encoder RE. Reference numeral 102 denotes a power supply voltage monitoring circuit that monitors the power supply of the power supply circuit 101. Is a light projecting element driving circuit for driving the light projecting element LED with power from the power supply circuit 101, and 105 is a detection circuit including the light receiving elements PDa and PDb. The detection circuit 105 outputs a-phase, b-phase, and ref-phase signals. The a phase signal is the output of the light receiving element PDa, the b phase signal is the output of the light receiving element PDb, and the ref phase signal is the reference signal. Reference numeral 106 denotes a comparator CPa, which compares the a-phase signal with the ref-phase signal to determine H or L of the A-phase signal, and 107 denotes an output A of the A-phase determination circuit 106. The phase output circuit 108 includes a comparator CPb, and compares the b-phase signal with the ref-phase signal to determine H or L of the B-phase signal. 109 denotes the B-phase determination circuit 108. A phase B output circuit 110 for outputting an output is a light receiving element operation determination circuit for determining the operation of the light receiving elements PDa and PDb from the output of the detection circuit 105.

  Reference numeral 111 denotes a monitoring CPU. A power supply voltage monitoring signal (1) from the power supply voltage monitoring circuit 102 and a drive circuit monitoring signal (2) for the light emitting element LED are connected to the AD conversion port A / D of the monitoring CPU 111. The a-phase signal (3) of the light-receiving element PDa, the b-phase signal (4) of the light-receiving element PDb, and the ref-phase signal (5) are input, and the A-phase signal determination signal (6) is input to the general-purpose port I / O. , A determination signal (7) for the B phase signal is input, and the output signal OUT A (8) of the A phase output circuit 107 and the output signal OUT B (9) of the B phase output circuit 108 are input to the interrupt port INT. Is done.

  The monitoring CPU 111 monitors the rotary encoder RE according to the monitoring item table shown in FIG. In this monitoring item table, the monitoring items of the rotary encoder RE are roughly divided into internal circuit monitoring and pulse signal monitoring. The monitoring items of the internal circuit are further divided into power supply voltage abnormality, light emitting element current abnormality, light receiving element output abnormality, and output circuit abnormality, and pulse signal monitoring is further divided into duty abnormality and high speed abnormality.

  In the internal circuit monitoring, the light emitting element LED makes a determination based on a voltage monitoring signal (2) of a constant current circuit (not shown), and the light receiving element uses a signal (3)-(5) from the light receiving element operation determining circuit 110, for example, It is determined whether or not the power supply common terminal CT of the light receiving elements PDa and PDb is connected, whether or not the wire bonding of the light receiving elements PDa and PDb is cut, an initial failure of the light projecting element LED, and the like. In the output circuit, the determination is made by comparing the determination signals (6) and (7) of the respective phase determination circuits 106 and 108 with the output signals (8) and (9) of the output circuits 107 and 109.

  In the pulse signal monitoring, when the rotary slit plate RS is rotating, the output period of the A phase signal and the B phase signal is counted, and the normality and abnormality of the duty of the A phase signal and the B phase signal are determined from the count result. To do. In this duty abnormality, the determination is made based on whether the duty of the A-phase signal and the B-phase signal is within a specified range. Moreover, when the rotation operation (high-speed rotation) more than expected is performed from the count result, it is determined as a high-speed abnormality.

  As described above, the monitoring CPU 111 monitors the internal circuit while the rotation is stopped (circle mark in the table of FIG. 3), and monitors the pulse signal during the rotation operation (marked by the mark x in the table of FIG. 3). Then, when the rotation is stopped, the monitoring CPU 111 switches to the monitoring item of the internal circuit and controls the electronic control device 207, which is a host device, to transmit a monitoring result of whether the internal circuit is normal or abnormal, and is rotating. Then, control is performed to switch to the monitoring item of whether or not the pulse signal is normally output and to notify the electronic control unit 207 of the monitoring result of whether the pulse signal is normal or abnormal. In this case, the monitoring CPU 111 outputs the monitoring result as, for example, a fail signal to the electronic control unit 207 via the fail (FAIL) output circuit 112.

   An electronic control system incorporating the rotary encoder RE of the embodiment will be described with reference to FIG. This electronic control system is a system for controlling an elevator apparatus. The elevator apparatus 201 drives a hoisting machine 202 by a driving motor 203 to raise and lower a passenger car 205 via a rope 204, while using a detected shaft. Both A and B phase signals, which are detection signals from the rotary encoder RE of the embodiment attached to the rotating shaft 206 of a certain driving motor 203, are input to the electronic control unit 207. The electronic control device 207 has a built-in control CPU, and drives and controls the drive motor 203 by a detection signal from the rotary encoder RE. The electronic control unit 207 includes a control CPU 208 and processes a signal from the rotary encoder RE.

  In the case of the rotary encoder RE according to the embodiment, when the rotation is stopped, the monitoring CPU 111 receives the signals (6) and (7) taken into the general-purpose port I / O and the signals taken into the AD conversion port A / D ( 1)-(5), normality / abnormality determination processing according to the table of FIG. 3 is performed and the determination result is transmitted to the electronic control unit 207. On the other hand, during rotation, the signal (8) taken into the external interrupt terminal INT In (9), normality / abnormality determination processing according to the table of FIG. 3 is performed, and the determination result is transmitted to the electronic control unit 207.

  Next, with reference to FIG. 5, the internal interrupt during the rotation stop will be described. When the rotation is stopped, the monitoring CPU 111 monitors the power supply voltage shown in the table of FIG. When AD conversion is performed for optical element voltage monitoring, reference voltage (PDref) monitoring, light receiving element PDa voltage monitoring, light receiving element PDb voltage monitoring, etc., and the AD conversion value is stored, and when the timer output changes from low level to high level The most recent AD conversion value (◯ mark) is taken in. While repeating this a predetermined number of times, the average value thereof is calculated, and the calculated average value is compared with the determination value to determine the abnormal state. The period during which the timer is at a high level is the processing time for these determinations.

  Further, during the rotation operation, the monitoring CPU 111 performs monitoring processing for the monitoring items shown in the table of FIG.

  As described above, in the embodiment, the monitoring item of the rotary encoder RE is the monitoring item (internal circuit monitoring in the table of FIG. 3) that performs signal processing when the rotation is stopped, and the item that is processed by external interrupt during the rotation operation. Since switching to (pulse signal monitoring in the table of FIG. 3), the monitoring item by the internal interrupt can be performed without being influenced by the external interrupt during the rotation operation.

  Next, referring to FIG. 6, signal waveforms of the A-phase signal and the B-phase signal are shown. 6A shows the phase difference (external interrupt timing) relationship when the A-phase and B-phase signals are normal, and FIG. 6B shows that the A-phase signal is normal and the B-phase signal is at a high level. This indicates the phase difference (external interrupt timing) relationship when there is an abnormality. As shown in FIG. 6A, when both the A-phase and B-phase signals are normal, the phase difference between the A-phase and B-phase signals (external interrupt timing) is 100% of the duty of the A-phase signal. It corresponds to 25%. FIG. 6B shows that the phase difference (external interrupt timing) from the rising edge to the falling edge of the A-phase signal when the B-phase signal is high is abnormal corresponds to 50%. .

  The operation of the embodiment will be described with reference to FIG. In the embodiment, the A phase signal is used for rotational speed detection. When monitoring is started by turning on the power of the rotary encoder RE, first, in step n1, it is determined whether the rotary encoder RE is rotating or not rotating. This rotation is performed by calculating the period of the A phase signal. That is, the bit counter counts, for example, one period from the rising edge to the next rising edge of the A phase signal. In addition, since the period calculation using such a counter is known, description is abbreviate | omitted.

  If the monitoring CPU 111 determines that the rotary encoder RE is not rotating at step n1, the monitoring CPU 111 sets the rotary encoder RE to the stop mode at step n2, and performs monitoring processing for the monitoring items during rotation stop according to the table of FIG.

  If the monitoring CPU 111 determines in step n1 that the rotary encoder RE is rotating, it calculates the phase difference between the A-phase and B-phase signals in step n3. This phase difference calculation is an external interrupt process. This phase difference is the phase difference described with reference to FIG.

  After calculating the phase difference at step n3, the monitoring CPU 111 determines that the phase difference is abnormal when the phase difference is, for example, 45% or more at step n4, and outputs a fail (FAIL) output at step n5. Is output to the control CPU 208 of the electronic control device 207, which is the host device.

  When the phase difference is less than 45%, for example, in step n4, the monitoring CPU 111 determines that the phase difference is normal, determines no, performs the subsequent duty calculation in step n6 by external interrupt processing, and in step n7, It is determined whether or not the duty calculation value is outside a predetermined range (for example, 30% or less or 70% or more). If the duty calculation value is outside the predetermined range, the duty is abnormal and it is determined as yes. At n8, a fail (FAIL) output is output to the control CPU 208 of the electronic control device 207, which is a host device. Further, the monitoring CPU 111 continues the monitoring process for the next (NEXT) monitoring item, assuming that the duty is normal when the duty calculation value is within the predetermined range.

  As described above, in the embodiment, the monitoring CPU 111 is incorporated, and when the non-rotation state is determined from the period calculation of the A-phase signal by the built-in monitoring CPU 111, the rotation stop mode is monitored as the rotation stop mode. When monitoring the internal circuit as an item and determining the rotation state, if the phase difference between the A-phase and B-phase signals is equal to or greater than a predetermined value, a process of outputting a fail output to the electronic control unit 207 is performed. If the calculated duty is outside the predetermined range, a process of outputting a fail output to the electronic control unit 207 is performed if the calculated duty is outside the predetermined range. The processing load can be greatly reduced and the abnormality of the corresponding pulse signal can be reliably detected. Required corresponding with the electronic control device 207 side tell your device 207 will be able to quickly take place, it contributes to the improvement of the safety and stability of the entire electronic control system incorporating the rotary encoder RE.

FIG. 1 is a diagram showing a schematic configuration of a rotary encoder according to an embodiment of the present invention. FIG. 2 shows the electrical configuration of the rotary encoder. FIG. 3 is a table showing monitoring items by the monitoring CPU. FIG. 4 is a diagram showing a configuration of an electronic control system in which the rotary encoder of the embodiment is incorporated. FIG. 5 is a diagram showing the monitoring timing by an internal interrupt while the rotary encoder rotation is stopped. 6A is a diagram showing a phase difference relationship between both signals when the A-phase and B-phase signals are normal, and FIG. 6B is a diagram showing a phase difference relationship between both signals when the B-phase signal is abnormal. is there. FIG. 7 is a flowchart for explaining the operation of the rotary encoder according to the embodiment. FIG. 8 is a diagram showing a general configuration of the rotary encoder. FIG. 9 is a diagram showing an electrical configuration of a conventional rotary encoder. FIG. 10 is a diagram showing signal waveforms of the A phase signal and the B phase signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Power supply circuit 102 Power supply voltage monitoring circuit 103 Emitting element drive circuit 104 Internal power supply 105 Detection circuit 106 A phase determination circuit 107 A phase output circuit 108 B phase determination circuit 109 B phase output circuit 111 Monitoring CPU
201 Elevator device 203 Motor 207 for driving Electronic control device (host device)

Claims (2)

A light emitting element;
A plurality of light receiving elements arranged opposite to the light projecting elements;
A circumferential plurality of rotary slits which rotates synchronously with the detection axis is disposed between the light projecting element and the light receiving elements,
Passage of light projected from the light projecting element with respect to the rotary slit, at least two pulse signals is 90 degrees phase difference using the output of the light receiving elements corresponding to the cut-off to the detection of the rotation state of the rotary encoder (A Phase Output circuit for generating and outputting a B-phase signal),
A monitoring CPU for monitoring the internal state of the rotary encoder with different monitoring items during rotation stoppage and during rotation operation,
The monitoring CPU, a determination the rotary encoder of whether the non-rotating state rotational state based on one of the pulse signals of the at least two pulse signals (A-phase signal), when determined that the non-rotating state , monitors for monitoring item during rotation stop, when determining the above rotational state, said at least two pulse signals (a-phase, B-phase signal) the phase difference is the higher-level device fail output equal to or greater than a predetermined value performs a process of outputting to, if the phase difference is less than the predetermined value, if the calculation result is out of the predetermined range performs arithmetic processing after the pulse signal, and outputs the fail output to the host apparatus A rotary encoder designed to perform processing. The monitoring CPU, said at least two of the rotating state from the period calculation of the rotary encoder of one pulse signal of the pulse signal (A-phase signal), determines the non-rotation state, the rotary of Claim 1 Encoder.

Images