JP5043636B2 - 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. 5 and subsequent drawings. FIG. 5 shows a mechanical configuration of the rotary encoder RE, FIG. 6 shows an electrical configuration of the rotary encoder RE, and FIG. The signal waveform of a phase signal and a B phase signal is shown.

  Referring to FIG. 5, 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. 6, 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, in the internal circuit monitoring, the monitoring process is performed at the timing of the internal interrupt of the CPU, and the pulse signal is attempted to be monitored at the timing of the external interrupt (change timing of the pulse signal). Burden is placed on it, which in effect affects monitoring. Therefore, the safety and stability of the entire electronic control system incorporating the rotary encoder RE are also affected.
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 is disposed between a light projecting element , a plurality of light receiving elements disposed opposite to the light projecting element, and between the light projecting element and each light receiving element, and rotates synchronously with a detected shaft. a circumferential plurality of rotary slits, a detection circuit for generating a signal for use in the rotation state detecting from the passage of the light projecting, outputs of the respective light receiving elements corresponding to the cut off from the light projecting element with respect to the rotary slit, said A rotary encoder comprising: an output circuit that generates and outputs pulse signals of various phases from an output signal of a detection circuit; and a monitoring CPU that monitors the internal state of the rotary encoder. item performs control to convey the first of said first monitored item to the host device is switched to the monitored item is normal or abnormal monitoring result to monitor an internal interrupts in a rotary stop, rotational movement Characterized in that is adapted to perform control to switch to the second monitoring item to be monitored by the external interrupt convey monitoring result if the second monitored item is normal or abnormal to the host device at medium is there.

In the present invention, during the rotation stop, so switched to monitor items that can monitor the first monitored item at the timing of the internal interrupt, without being affected by the external interrupt, it can be reliably monitored. Then, during the rotating operation, the switching to the second monitoring items for monitoring the monitoring item at the timing of the external interrupt, without being affected by the internal interrupt can be reliably monitored.

  As a result, in the present invention, the monitoring CPU can stably and reliably monitor and control the state of the rotary encoder, and can stably transmit the monitoring result to the host device.

In a preferred aspect of the present invention, the first monitoring item in the internal interrupt is an item relating to the state of the internal circuit.

In a preferred aspect of the present invention, the second monitoring item in the external interrupt is a state of a pulse signal.

  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. , The determination signal (7) of the B phase signal, 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. The output signal OUT A (8) of the phase output circuit 107 and the output signal OUT B (9) of the B phase output circuit 108 are input.

  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.

  As described above, in the present embodiment, the monitoring item of the rotary encoder RE is a monitoring item (internal circuit monitoring in the table of FIG. 3) that performs signal processing with an internal interrupt when rotation is stopped, and is processed with an external interrupt during rotation operation. Since the item is switched to the item (pulse signal monitoring in the table of Fig. 3), during the rotation operation, the monitoring item by the internal interrupt can be judged stably without being affected by the external interrupt, while the rotation Since the state of each internal circuit of the rotary encoder RE is monitored during the stop, the abnormality of the rotary encoder RE can be transmitted before the device to be controlled moves, and the rotary encoder RE Since the pulse signal is monitored, the safety of the entire electronic control system can be achieved.

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 a general configuration of the rotary encoder. FIG. 6 is a diagram showing an electrical configuration of a conventional rotary encoder. FIG. 7 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 (3)

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,
A detection circuit for generating a signal for use in the rotation state detecting passage of the light projection, from the output of the light receiving elements corresponding to the cut off from the light emitting element to said rotation slit,
An output circuit for generating and outputting pulse signals of various phases from the output signal of the detection circuit;
A rotary encoder comprising a monitoring CPU for monitoring the state inside the rotary encoder,
The monitoring CPU performs control to switch the monitoring item to the first monitoring item to be monitored by an internal interrupt while the rotation is stopped, and to notify the host device of the monitoring result of whether the first monitoring item is normal or abnormal,
In a rotary operation is adapted to perform control to switch to the second monitoring items to be monitored by the external interrupt convey monitoring result if the second monitored item is normal or abnormal on the host device, a rotary encoder. The rotary encoder according to claim 1, wherein the first monitoring item monitored by the internal interrupt is an item related to a state of an internal circuit. The rotary encoder according to claim 1, wherein the second monitoring item monitored by the external interrupt is an item related to a state of a pulse signal.

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