JP2009128060A - Rotary encoder and electronic control system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rotary encoder which enables safe operation of a system on the electronic control unit side. <P>SOLUTION: This rotary encoder 11 comprises main-system and sub-system circuits which form respectively an A phase signal, a B phase signal and a reference phase signal and a microcomputer which determines whether the main-system circuit is normal or abnormal, and outputs the A phase signal and the B phase signal from the main-system circuit when this circuit is determined as normal, while performing a control for switchover to the side whereon the A phase signal and the B phase signal are outputted from the sub-system circuit, when the main-system circuit is determined as abnormal. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to an abnormal phase output function in an absolute type or incremental type rotary encoder.

  The rotary encoder of the present invention receives a light signal from a light projecting element that has passed through a plurality of circumferential slits rotating in synchronization with a detected shaft by a plurality of light receiving elements, and receives light from the light receiving element in response to the light reception. This encoder obtains rotation information of the detected shaft from both A and B phase signals generated and output from the output.

  Referring to FIG. 8, the incremental rotary encoder 11 generally transmits light from the light projecting element LED at equal intervals in the circumferential direction between the light projecting element LED and the two light receiving elements PD1 and PD2. A rotary slit plate RS having a plurality of slits (hereinafter referred to as rotary slits), and a slit that can transmit light from the light projecting element LED on one side of the rotary slit plate RS, similar to the slits. A fixed slit plate FS (hereinafter referred to as “fixed slit”) is disposed oppositely (Patent Document 1).

  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 light receiving elements PD1 and PD2 receive the above optical signals, and the control means CPU generates A phase signals and B phase signals as shown in FIGS. 9A and 9B from the light receiving outputs of the light receiving elements PD1 and PD2. The rotation state of the detected shaft, that is, the rotation direction and the rotation speed can be detected from the A phase and B phase signals.

  In the detection of the rotational direction, as shown in FIG. 9C, the binary code of the A phase and B phase signals is “0” for the combination of the A phase signal “0”, the B phase signal “0”, and the 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 phase signal“ 1 ” The combination is “1”, and the rotation direction can be determined from the change order of the binary code. The binary code changes as “0” “2” “3” “1” “0” “2”... And the total signal level is “0” “1” “2” “1” “0” “1”. Change.

  In the combination of the binary code of the A phase signal and the B phase signal, there are “0” and “0” combinations. In this case, in the rotary encoder, since the light receiving elements PD1 and PD2 are commonly connected to the power supply common terminal CT as shown in FIG. 10, even when the power common terminal CT is not connected to the light receiving elements PD1 and PD2. In the combination of the binary code of the A phase signal and the B phase signal, a combination of “0” and “0” is established. The light reception outputs of the light receiving elements PD1 and PD2 are compared by the comparison circuits CP1 and CP2, respectively, and an A phase signal and a B phase signal are generated.

  Therefore, in the conventional rotary encoder 11, when the light receiving elements PD1 and PD2 are not connected to the power supply common terminal CT, the rotational state of the detected shaft is erroneously detected, and the reliability of the apparatus or system on which the rotary encoder is mounted is detected. There is a problem that it becomes a factor of lowering.

  In order to make it possible to detect an unconnected state to the power supply common terminal CT, the present applicant reverses the signal level every 180 degrees, and the signal levels of the A phase signal and the B phase signal are both Based on at least three signal levels of the A phase, the B phase, and the reference phase (ref), the power supply common terminal CT is configured to generate the reference phase signal that is inverted to the rising side at the timing of zero. A rotary encoder provided with a determination means for determining whether or not a plurality of light receiving elements PD1 and PD2 are not connected has been considered (see Japanese Patent Application No. 2007-127857, filed on May 14, 2007).

  By the way, when the rotary encoder is incorporated in an electronic control system together with an electronic control unit that inputs both the signals from the rotary encoder and electronically controls the rotation operation of the detected shaft based on the both signals, the rotary encoder A When one of the phase, the B phase, and the reference phase (ref) is out of order, in the case of failure, for example, the signal level “1” (= ON), and in the case of normal, for example, the signal level “0” ( = OFF) is simply output to the electronic control device side, and the electronic control device side does not know which of the above phases has failed. Therefore, the safety of the electronic control system is determined by the failsafe signal. From the standpoint of achieving this, it was difficult to respond to other than stopping the system operation.

In addition, even if the electronic control device can take emergency measures such as stopping the system operation by inputting the fail-safe signal, if an emergency measure such as stopping the system operation is taken immediately after the input of the fail-safe signal, for example, an elevator This is inconvenient if the car is on the middle floor. On the other hand, even if the system is constructed so that the car can be raised and lowered up to the nearby floor, it is an emergency evacuation measure, and it is difficult to deny the possibility of stopping during the raising and lowering. Therefore, as a result of diligent research, the present applicant has been able to invent a rotary encoder that can safely operate the system even if there is an abnormality on both the A and B phase signal generation sides.
Japanese Patent Laid-Open No. 07-134048

  The problem to be solved by the present invention is to provide a rotary encoder that enables safe system operation on the electronic control unit side.

  The rotary encoder according to the present invention includes a plurality of light receiving elements that receive light projected from the light projecting elements through a rotating slit that rotates in synchronization with the detected shaft, and obtains rotation information of the detected shaft from the light reception output of these light receiving elements. In the rotary encoder that generates the detection signal including the A phase signal that inverts every 180 degrees in electrical angle as the detection signal, and the B phase signal that inverts by 90 degrees in electrical angle from the A phase signal and inverts every 180 degrees A system circuit, a sub-system circuit that generates the A-phase signal and the B-phase signal in a circuit configuration different from the main system circuit as the detection signal, and whether the main system circuit is normal or abnormal Control means for controlling the output of both the A and B phase signals from the main system circuit at the time, and switching the control from the sub system circuit to the output side of both the A and B phase signals at the time of abnormality determination. We are an butterfly.

  In the present invention, the microcomputer switches to the sub system circuit when either of the two phases breaks down while the A and B phase signals are being output from the main system circuit to the electronic control unit side. The system operation can be continued on the control device side. Also, if a fail-safe signal is output from the rotary encoder side to the electronic control unit due to the above failure, etc., even if the cause of the failure on the rotary encoder side is unknown on the electronic control side, the fail-safe signal is input. It is not necessary to stop the system operation immediately, and the system operation can be performed safely. Further, when switching to the sub system circuit, there is a failure or the like in the main system, so the system administrator or the like can perform maintenance for the failure or the like of the rotary encoder and eliminate the cause of the failure.

  According to a preferred aspect of the present invention, a reference phase signal is generated that inverts the signal level every 180 degrees and inverts to the rising side at a timing when both of the signal levels of the A phase signal and the B phase signal are zero. A reference phase signal generation circuit, wherein the control means is connected to the power supply common terminal in common with the plurality of light receiving elements based on at least the signal levels of the A phase, the B phase, and the reference phase (ref), It is determined whether it is not connected, and when it is not connected, output control of a fail-safe signal is performed.

  To explain this aspect, the sum of the signal levels of the A phase signal and the B phase signal is zero at the combination timing of “0” and “0” in the binary code combination of the A phase signal and the B phase signal. When the signal level of the reference phase signal is inverted to the rising side, the sum of the signal levels of the A phase, the B phase, and the reference phase does not become zero, so it is determined that the light receiving element is connected to the power supply common terminal. be able to. On the other hand, in the combination of the binary code of the A phase signal and the B phase signal, the sum of the signal levels of the A phase signal and the B phase signal is zero at the timing of the combination of “0” and “0”. When the power supply common terminal is not connected to the light receiving element at this timing, the signal level of the reference phase signal is not inverted to the rising side, the signal level of the reference phase signal is zero, and the A phase, B phase, The sum of the signal levels of the three reference phases becomes zero, and it can be determined that the light receiving element is not connected to the power supply common terminal. As a result, in the rotary encoder according to the present invention, the behavior of an apparatus or system on which the rotary encoder is mounted can be controlled before the operation from the above determination, so that the reliability is improved.

  According to a preferred aspect of the present invention, a reference phase signal is generated that inverts the signal level every 180 degrees and inverts to the rising side at a timing when both of the signal levels of the A phase signal and the B phase signal are zero. The control means includes a reference phase signal generation circuit, and the control means detects at least one of the three signals including the A phase signal, the B phase signal, and the reference phase signal, and based on the detection, detects the three parties. As data for specifying which phase of the signals is abnormal, any one of combination data of a plurality of bit signals, combination data of duty within one cycle of a single signal, and communication data Output control.

  In this aspect, since the electronic control device side knows which phase of the A phase signal, the B phase signal, and the reference phase signal is abnormal from the above data, on the electronic control device side, for example, the A phase, When only the reference phase (ref) is the abnormal phase among the B phase and the reference phase (ref), the system operation can be continued with the signals of the A phase and the B phase without stopping the system. If only the A phase or only the B phase is an abnormal phase, the electronic controller side cannot judge whether the detected axis is rotating forward or reverse, but the system should be temporarily operated with a normal A phase or B phase signal. When both the A phase and the B phase are abnormal phases, the system can be tentatively operated with a reference phase (ref) signal.

  The present invention can be applied to both an absolute type rotary encoder and an incremental type rotary encoder.

  According to the present invention, it is possible to provide a rotary encoder that enables safe operation of the system on the electronic control device side even if there is an abnormality on both the A and B phase signal generation sides.

  Hereinafter, a rotary encoder according to an embodiment of the present invention and an electronic control system including the rotary encoder will be described in detail with reference to the accompanying drawings. In the embodiment, the present invention is applied to an electronic control system that controls an elevator, but the present invention can also be applied to other electronic control systems.

  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. In the electronic control device 13, the drive motor 5 is driven and controlled 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.

  The basic configuration of the rotary encoder 11 according to the embodiment will be described with reference to FIG. 3. The light projecting element LED is inserted and connected in series with the current limiting resistor R0 and the transistor TR0 between the power source and the ground, and a drive circuit (not shown). The light projecting operation is performed through the transistor TR0 which is turned on / off by the output.

  On the light receiving element side, a main system circuit and a sub system circuit are provided. Both the main system and the sub system include A phase signal generation circuits MainA and SubA, B phase signal generation circuits MainB and SubB, reference phase signal generation circuits MainR and SubR, Have

  In the main system circuits MainA, MainB, and MainR, light projection from the light projecting element LED is performed by the light receiving elements PD (a +), PD (a−), and PD (b +) through the rotating slit plate RS and the fixed slit plate FS. , PD (b−), PD (ref +), and PD (ref−). The meaning of (a +),... Of the light receiving element PD will be described later. The rotary slit plate RS and the fixed slit plate FS are schematically shown for convenience of illustration. The outputs of these light receiving elements PD (a +), PD (a−), PD (b +), PD (b−), PD (ref +), PD (ref−) are compared by the comparison circuits CP1, CP2, CP3, The comparison circuit CP1 outputs a main A phase signal (A), the comparison circuit CP2 outputs a main B phase signal (B), and the comparison circuit CP3 outputs a main reference phase signal (ref). The main A phase signal and the main B phase signal are output to the electronic control unit 13 via the output circuit units RD1 and RD2, and the main reference phase signal (ref) is output together with the main A phase signal and the main B phase signal. The data is input to the microcomputer MC serving as control means via the unit RD3.

  In each of the sub-system circuits SubA, SubB, SubR, the light projection from the light projecting element LED is received by the light receiving elements PD ′ (a +), PD ′ (a−), PD via the rotating slit plate RS and the fixed slit plate FS. ′ (B +), PD ′ (b−), PD ′ (ref +), and PD ′ (ref−) receive light. The meaning of (a +),... Of the light receiving element PD will be described later. The rotary slit plate RS and the fixed slit plate FS are schematically shown for convenience of illustration. The outputs of these light receiving elements PD ′ (a +), PD ′ (a−), PD ′ (b +), PD ′ (b−), PD ′ (ref +), PD ′ (ref−) are output from the comparison circuit CP1 ′, The comparison circuit CP1 ′ compares the sub A phase signal (A ′), the comparison circuit CP2 ′ sub sub phase B signal (B ′), and the comparison circuit CP3 ′ sub reference phase signal (B ′). ref ′) is output. The sub A phase signal and the sub B phase signal are output to the electronic control unit 13 via the output circuit units RD1 ′ and RD2 ′, and the sub reference phase signal (ref ′) together with the sub A phase signal and the sub B phase signal. Are switched and input to the microcomputer MC via the output circuit section RD3 ′.

  The microcomputer MC can determine whether or not the power common terminal CT is not connected based on the main A-phase signal, the main B-phase signal, and the main reference phase signal. Further, the microcomputer MC determines whether or not there is a failure in each main system circuit. If there is a failure, the microcomputer MC switches to each circuit in the sub system, and uses the sub A phase signal, the sub B phase signal, and the sub reference phase signal for power supply common. It is possible to determine whether or not the terminal CT is unconnected.

  In this case, the main circuits MainA, MainB, and MainR are connected to the normally closed contacts NC of the changeover switches SW1, SW2, and SW3, and the sub circuits SubA, SubB, and SubR are connected to the normally open contacts NO of the changeover switches SW1, SW2, and SW3. The change-over switches SW1, SW2, and SW3 are switched by a contact switching drive unit CC that responds to a control command of the microcomputer MC. In the embodiment, the changeover switch is used for switching between the main system and the sub system for the sake of illustration, but the present invention is not limited to this.

  In the rotary encoder 11 described above, when the main circuits MainA, MainB, and MainR are normal, the light projecting element LED, the rotating slit rs, the fixed slit fs, the light receiving elements PD (a +), PD (a−), and PD ( b +), PD (b−), PD (ref +), PD (ref−), and comparison circuits CP1, CP2, CP3, and a main A-phase signal whose signal level is inverted every 180 degrees, and an electrical angle from the A-phase. A main B-phase signal whose signal level is inverted every 180 degrees with a 90-degree phase shift, and a signal level which is inverted every 180 degrees, and the signal levels of the main A-phase signal and the main B-phase signal are both zero. A main reference phase signal that is inverted to the rising side at the timing is generated. When the main circuits MainA, MainB, and MainR are switched to sub-system circuits SubA, SubB, and SubR due to a failure or the like, the light projecting element LED, the rotating slit rs, the fixed slit fs, the light receiving element PD ′ (a +), PD ′ (a−), PD ′ (b +), PD ′ (b−), PD ′ (ref +), PD ′ (ref−), and comparison circuits CP1 ′, CP2 ′, CP3 ′, signals at 180 degrees. A sub A phase signal whose level is inverted, a sub B phase signal whose phase is shifted by 90 degrees in electrical angle from the A phase and whose signal level is inverted every 180 degrees, and a signal level which is inverted every 180 degrees and A sub-reference phase signal that is inverted to the rising side is generated at the timing when the signal levels of the A-phase signal and the sub-B phase signal are both zero.

  The mechanical configuration of the rotary encoder according to the embodiment will be described with reference to FIG. FIG. 4A shows the main system and FIG. 4B shows the sub system.

  In the main system of FIG. 4A, rs are rotating slits formed in the rotating slit plate RS at equal intervals in the circumferential direction. In the drawing, in the rotary slit plate RS, the portion of the rotary slit rs is white in the illustration, and the portion between the rotary slits rs is a portion that blocks light projection of the light projecting element LED, and is indicated by hatching in the illustration. The fixed slit plate FS has a fixed slit fs opposed to the rotating slit rs. For convenience of explanation, the fixed slit fs is fs (a +) which generates the optical signal a + that inverts the light of the light projecting element LED every 180 degrees, and the electrical angle is shifted 180 degrees from the optical signal a + by 180 degrees. The fixed slit for generating the optical signal a− that is inverted every degree is fs (a−), and the light of the light projecting element LED is shifted by 90 degrees in electrical angle from the optical signal a +, and the optical signal b + that is inverted every 180 degrees is generated. The fixed slit is fs (b +), and the fixed slit for generating the optical signal b− that is shifted by 180 degrees in electrical angle with respect to the optical signal b + and is inverted every 180 degrees is fs (b−), the optical signal a + and the optical signal b +. The fixed slit that generates the optical signal ref + whose signal level rises every 180 degrees rises at a timing when both of the optical signal a and the optical signal b- are both zero. The stationary slit for generating an optical signal ref- whose signal level at each rising 180 degrees reversed at timing referred to fs (ref-).

 The main light receiving element PD also has PD (a +) in accordance with the respective fixed slits fs (a +), fs (a−), fs (b +), fs (b−), fs (ref +), and fs (ref−). ), PD (a−), PD (b +), PD (b−), PD (ref +), PD (ref−), and the respective light receiving elements PD (a +), PD (a−), PD (B +), PD (b−), PD (ref +), and PD (ref−) are the corresponding fixed slits fs (a +), fs (a−), (b +), fs (b−), and fs (ref +). ), Fs (ref−), and the optical signals a +, a−, b +, b−, ref +, and ref− are received. The outputs of the light receiving elements PD (a +) and PD (a−) that receive the optical signals a + and a−, respectively, are compared by the comparator circuit CP1 as described above to generate an A phase signal, and the optical signals b + and b− are generated. As described above, the outputs of the light receiving elements PD (b +) and PD (b−) that respectively received the light are compared by the comparison circuit CP2 to generate the B phase signal, and the light receiving elements that respectively received the optical signals ref + and ref−. The outputs of PD (ref +) and PD (ref−) are compared by the comparison circuit CP3 as described above to generate a reference phase signal.

  Since the sub system shown in FIG. 4B corresponds to the main system shown in FIG. 4A, the description thereof is omitted. The rotary encoder 11 according to the embodiment has the main system and the sub system as described above, and if the main system has an abnormality, it only switches to the sub system, and the main system and the sub system are the same. .

  Referring to FIGS. 5A to 5C, the A phase signal (A, A ′) and the B phase signal (B, B ′) of the main system and the sub system are output circuits RD1-RD3, RD1′−. The signal is converted into a digital A-phase signal and B-phase signal shown in FIGS. 5A and 5B inside the RD 3 ′. In binary code, A phase signal is “0”, B phase signal is “0”, “0”, A phase signal is “1”, B phase signal is “0”, “2”, A phase signal Is “1” and the phase B signal is “1”, the timing is “3”, the phase A signal is “0”, and the phase B signal is “1”. The timing is “0”, “2”, “ In the order of “3” and “1”, as described in the background art, it is possible to detect and determine that the rotation direction is one side, for example, clockwise, and in the reverse order, counterclockwise. Further, the rotational speed can be detected by counting the number per unit time such as the A phase signal.

  Then, the microcomputer MC inputs the three party signals of the A phase signal, the B phase signal, and the reference phase signal, and all the three signal levels of the inputted A phase signal, B phase signal, and reference phase signal become zero. In this case, it is determined that the power supply common terminal CT is not connected. That is, the microcomputer MC is not at the same time that the A phase signal, the B phase signal, and the reference phase signal (ref) shown in FIGS. While it is determined that the common terminal CT is not disconnected, although not shown in FIGS. 5A to 5C, the A phase signal (A, A ′), the B phase signal (B, B ′), When there is a timing when all the signal levels of the reference phase signals (ref, ref ′) become zero, it is determined that the power supply common terminal CT is not connected at that timing.

  As described above, in the embodiment, it is possible to determine that the light receiving element is not connected to the power supply common terminal CT in both the main system and the sub system. As a result, in the rotary encoder of the embodiment, The reliability of the system will be improved.

  With reference to FIG. 6, the block configuration of the electronic control system of the embodiment will be described. In FIG. 6, only the microcomputer MC is shown in the rotary encoder 11. The 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.

  The microcomputer MC of the rotary encoder 11 includes a phase signal input unit M1, a light projecting element driving unit M2, a fail safe signal output unit M3, a CPU M4, a memory M5, and a main / sub system circuit switching unit M7. . These are interconnected by an internal bus M6.

  In the microcomputer MC, the phase signal input unit M1 inputs and processes the A phase signal, the B phase signal, and the reference phase signal of each of the main system and the sub system. The light projecting element driving unit M2 outputs a driving signal to the transistor TR0. The fail safe signal output unit M3 outputs a fail safe signal to the electronic control device 13 when the rotary encoder 11 is abnormal in operation. The electronic control device 13 ensures the safety of the electronic control system by controlling the rotation of the driving motor 5 to the safe side in response to the fail safe signal.

  The memory M5 includes various memories such as a flash memory, a mask ROM, and a RAM. The memory M5 stores an execution program for the CPU M4 to execute the operation of the entire rotary encoder 11, an operation abnormality determination program for the CPU M4 to perform an operation abnormality determination, and other programs.

  The operation abnormality determination program will be described with reference to FIG.

  The CPU M4 constitutes detection means for detecting which of the A phase signal, the B phase signal, and the reference phase signal has failed. The CPU M4 can also constitute an abnormal phase output means according to any of the following (1) to (3).

  (1) The CPU M4 and the fail safe signal output unit M3 output abnormal phase output means for outputting combination data of a plurality of bit signals as data for specifying which phase of the three signals is an abnormal phase. Configure.

  This abnormal phase output means will be described with reference to FIG.

  Two first and second failsafe signals are output from the failsafe signal output unit M3. These first and second fail-safe signals are the bit signals.

  When the reference phase (ref) is an abnormal phase, the CPU M4 sets the first failsafe signal to “0” and the second failsafe signal to “0” in FIG. A second fail safe signal is output. In the electronic control unit 13, both the fail-safe signals are regarded as 2-bit signals, and the combination of “00” makes it possible to grasp that the reference phase (ref) is an abnormal phase. The system operation can be continued with the phase and B phase signals.

  When the phase A is an abnormal phase, the CPU M4 sets the first failsafe signal to “0” and the second failsafe signal to “1” in FIG. Output a signal. In the electronic control unit 13, both the fail-safe signals are regarded as 2-bit signals, and the combination of “01” makes it possible to grasp that the A phase is an abnormal phase. Although the control device 13 cannot do this, the system can be tentatively operated with a normal B-phase signal.

  When the B phase is an abnormal phase, the CPU M4 sets the first failsafe signal to “1” and the second failsafe signal to “0” in FIG. Output a signal. In the electronic control unit 13, both the fail-safe signals are regarded as 2-bit signals, and the combination of “10” makes it possible to grasp that the B phase is an abnormal phase. Although the controller side cannot do it, the system can be tentatively operated with a normal A-phase signal.

  When both the A phase and the B phase are abnormal phases, the CPU M4 sets the first failsafe signal to “1” and the second failsafe signal to “1” in FIG. A second fail safe signal is output. The electronic control unit 13 regards both the failsafe signals as 2-bit signals, and can recognize that both the A phase and the B phase are abnormal phases by the combination of “11”, and the signal of the reference phase (ref) The system can be tentatively operated.

  (2) Further, the CPU M4 and the fail safe signal output unit M3 use the combination data of duty within one cycle of a single signal as data for specifying which phase of the above three signals is an abnormal phase. The abnormal phase output means for outputting is configured.

  This abnormal phase output means will be described with reference to FIG.

  From the fail safe signal output unit M3, a fail safe signal having a duty corresponding to each of the abnormal phases of the A phase, the B phase, and the reference phase (ref) is output to the electronic control unit 13.

  When the reference phase (ref) is an abnormal phase, the CPU M4 sets the duty of the fail safe signal to 50% in FIG. 7B and outputs the fail safe signal to the electronic control device 13 side. In the electronic control unit 13, when the duty of the fail safe signal is 50%, the reference phase (ref) can be grasped as an abnormal phase, and the system is not shut down, and the signals of the A phase and the B phase are used. System operation can be continued.

  When the phase A is an abnormal phase, the CPU M4 sets the fail safe signal duty to 30% in FIG. 7B and outputs the fail safe signal to the electronic control device 13 side. In the electronic control unit 13, when the duty of the fail-safe signal is 30%, it is possible to grasp that the A phase is an abnormal phase, and the electronic control unit 13 cannot determine whether the motor 5 is rotating forward or backward. The system can be temporarily operated with a normal B-phase signal.

  When the B phase is an abnormal phase, the CPU M4 sets the duty of the fail safe signal to 20% in FIG. 7B and outputs the fail safe signal to the electronic control device 13 side. In the electronic control unit 13, when the duty of the fail safe signal is 20%, it can be understood that the B phase is an abnormal phase, and the electronic control unit 13 cannot determine whether the motor 5 is rotating forward or backward. The system can be temporarily operated with a normal A-phase signal.

  When both the A phase and the B phase are abnormal phases, the CPU M4 sets the duty of the fail safe signal to 10% in FIG. 7B and outputs the fail safe signal to the electronic control device 13 side. The electronic control unit 13 can grasp that the A phase and the B phase are both abnormal when the duty of the fail-safe signal is 10%, and tentatively operate the system with the reference phase (ref) signal. Can do.

  (3) Further, the CPU M4, as an abnormal phase output means, transmits data specifying which of the three signals is an abnormal phase to a CPU (not shown) on the electronic control unit (ECU) 13 side. Data communication. The CPU M4 transmits a communication signal including data corresponding to the abnormal phases of the A phase, the B phase, and the reference phase (ref) to an unillustrated CPU of the electronic control unit (ECU) 13. In this data communication, mutual data is transmitted between the CPU M4 of the rotary encoder 11 and a CPU (not shown) of the electronic control unit (ECU) 13 by using a communication port such as UART (Universal Asynchronous Receiver Transmitter). Can be sent and received. Alternatively, a simple system such as a CSI (Clocked Serial Interface) system may be used instead of the UART system. In this CSI method, data is transmitted and received by clock synchronous communication through the signal terminals of the CPU M4 of the rotary encoder 11 and the CPU (not shown) of the electronic control unit (ECU) 13.

  In the above embodiment, when the CPU M4 determines that the main system circuit is abnormal by monitoring the A phase signal, the B phase signal, and the reference phase signal of the main system, the main system / sub system circuit switching unit. M7 is controlled to switch the selector switches SW1, SW2, and SW3 to the normally open contact NO. As a result, the A phase signal (A ′), the B phase signal (B ′), and the reference phase signal (ref ′) are input from each circuit in the sub system. The CPU M4 simultaneously outputs a fail safe signal from the fail safe signal output unit M3 to the electronic control device 13 side.

  On the electronic control unit 13 side, even if there is a failure or the like in each main system circuit, the rotary encoder 11 outputs the A phase signal (A ′), B phase signal (B ′), and reference phase signal (ref) from each sub system circuit. ′) Is input, the system operation can be continued, and it can be determined from the fail-safe signal that there is an abnormality in the rotary encoder 11 and at the same time, which phase abnormality is caused by the abnormality can be determined. it can.

  In this case, in the electronic control system including the rotary encoder 11 and the electronic control device 13 according to the embodiment, only the reference phase (ref) is an abnormal phase among the A phase, the B phase, and the reference phase (ref). The system operation can be continued with the A-phase and B-phase signals without stopping the system operation, and when only the A-phase or only the B-phase is an abnormal phase, it is determined whether the motor shaft 10 is rotating forward or reverse. The electronic control unit 13 cannot perform the operation, but the system can be tentatively operated with a normal A-phase or B-phase signal. If both the A-phase and B-phase are abnormal phases, the reference phase (ref) signal The system can be tentatively operated.

  As described above, in the embodiment, when either of the two phases breaks down while the A and B phase signals are being output from the main system circuits to the electronic control unit 13 side, the microcomputer MC Can switch to each circuit of the sub system and output both A and B phase signals of the sub system similar to the main system to the electronic control device 13, so that the system operation can be continued on the electronic control device 13 side. Further, when a fail-safe signal is output from the rotary encoder 11 side to the electronic control device 13 side due to the above-mentioned failure or the like, the electronic control device 13 side may fail even if the cause of the failure on the rotary encoder 11 side is unknown. By inputting the safe signal, it is not necessary to immediately stop the system operation, and the system operation can be performed safely. Further, when switching to each circuit of the sub system, a failure or the like exists in the main system, so that the system administrator or the like can perform maintenance for the failure or the like of the rotary encoder 11 and eliminate the cause of the failure.

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 electrical configuration of the rotary encoder according to the embodiment of the present invention. FIG. 4 is a diagram for explaining the correspondence between the rotary slit and the fixed slit. FIG. 5 is a diagram illustrating a relationship among signal levels of the A-phase signal, the B-phase signal, and the reference phase (ref) signal. FIG. 6 is a block diagram showing a microcomputer, an electronic control unit (ECU), and a drive motor of the rotary encoder according to the embodiment. FIG. 7A is a diagram showing an example in which an abnormal phase is specified by a combination of two failsafe signals, and FIG. 7B is a diagram showing an example in which an abnormal phase is specified by a combination of the duty of the failsafe signal. FIG. 8 is a view showing a schematic mechanical configuration of a conventional rotary encoder. 9A is a diagram showing an A-phase signal, FIG. 9B is a B-phase signal, and FIG. 9C is a diagram showing a binary code and a signal level sum. FIG. 10 is a diagram showing a schematic electrical configuration of a conventional rotary encoder.

Explanation of symbols

11 Rotary encoder 13 Electronic control device PD Light receiving element MC Microcomputer (control means)

Claims (5)

A plurality of light receiving elements that receive light emitted from the light projecting elements through rotating slits that rotate synchronously with the detected axis, and that generates a detection signal including rotation information of the detected axis from the light reception output of these light receiving elements. In the encoder
A main system circuit that generates an A phase signal that is inverted every 180 degrees in electrical angle as the detection signal, and a B phase signal that is inverted by 90 degrees in electrical angle from the A phase signal and is inverted every 180 degrees;
A sub system circuit for generating the A phase signal and the B phase signal in a circuit configuration different from the main system circuit as the detection signal;
Whether the main system circuit is normal or abnormal is determined, and when the normal determination is made, both the A and B phase signals are output from the main system circuit. When the abnormality is determined, both the A and B phase signals are output from the sub system circuit. Control means for switching control to the side to perform,
A rotary encoder comprising: A circuit that generates a reference phase signal that inverts the signal level every 180 degrees and that inverts to the rising side at the timing when both of the signal levels of the A phase signal and the B phase signal are zero;
The control means determines whether the plurality of light receiving elements are commonly connected to the power supply common terminal or not based on at least three signal levels of the A phase, the B phase, and the reference phase (ref). In addition, when not connected, the output of the fail safe signal is controlled.
The rotary encoder according to claim 1. A circuit that generates a reference phase signal that inverts the signal level every 180 degrees and that inverts to the rising side at the timing when both of the signal levels of the A phase signal and the B phase signal are zero,
The control means detects which of the three signals including at least the A phase signal, the B phase signal, and the reference phase signal has failed, and based on this detection, which phase of the three signals is detected. As the data for specifying whether or not is abnormal, output control is performed for any one of a combination data of a plurality of bit signals, a combination data of duties within one cycle of a single signal, and communication data.
The rotary encoder according to claim 1.   4. The rotary encoder according to claim 1, wherein the control means is constituted by a microcomputer. A rotary encoder that outputs an A-phase signal that is inverted every 180 degrees in electrical angle and a B-phase signal that is shifted by 90 degrees in electrical angle from the A phase signal and inverted every 180 degrees as the detected shaft rotates;
An electronic control device with a built-in microcomputer for inputting both the signals from the rotary encoder and electronically controlling the rotation operation of the detected shaft based on the both signals;
In an electronic control system with
An electronic control system using the rotary encoder according to claim 4 as the rotary encoder.

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