JP2013137255A - Encoder and method of controlling the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an encoder capable of reducing power consumption thereof while operating on power supplied from a backup battery when power from a main power source is unavailable.SOLUTION: When an encoder 1, which detects absolute rotational angular position of a rotor body, is in backup mode where power from a main power source 3 is unavailable and the encoder 1 operates on power supplied from a backup battery 4, a detector section for detecting number of turns the rotor body has rotated from a preset position of origin is turn on and off at a preset sampling period, and a signal processor section for processing an output signal from the detector section generates a square wave detection signal based on the output signal from the detector section and samples the level of the detection signal at the sampling period. The encoder 1 changes the sampling period in accordance with the sampled level of the detection signal in backup mode.

Description

  The present invention relates to an encoder for detecting an absolute position of a rotation angle of a rotating body and an encoder control method.

  Conventionally, an absolute encoder for detecting an absolute position of a rotation angle of a rotating body is known (see, for example, Patent Document 1). The absolute encoder described in Patent Document 1 includes a backup battery. When the supply of power from the main power supply is stopped, the absolute encoder operates using the power supplied from the backup battery. Therefore, this absolute encoder can generate and hold multi-rotation data indicating how many times the rotating body is rotating from a predetermined origin position even in the backup mode in which the power supply from the main power supply is stopped. it can.

JP 2010-2267 A

  As described above, the absolute encoder described in Patent Document 1 operates with the power supplied from the battery in the backup mode in which the supply of power from the main power supply is stopped. Therefore, in this absolute encoder, if the power consumption of the encoder in the backup mode is large, the amount of battery discharge increases, and it is necessary to frequently charge or replace the battery. That is, in this absolute encoder, maintenance becomes complicated when the power consumption of the encoder in the backup mode is large.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an encoder capable of reducing power consumption when operating with power supplied from a backup battery after power supply from a main power supply is stopped. . Another object of the present invention is to provide an encoder control method capable of reducing power consumption when the power supply from the main power supply is stopped and the operation is performed by the power supplied from the backup battery. There is to do.

  In order to solve the above-described problems, an encoder according to the present invention is an encoder that is connected to a main power source and a backup battery and can detect the absolute position of the rotation angle of the rotating body. Provided with a detection unit for detecting how many rotations from the position and a signal processing unit for processing the output signal output from the detection unit, supply of power from the main power supply is stopped and supplied from the battery When the encoder mode corresponding to the operation of the encoder by the generated power is the backup mode, in the backup mode, the detection unit starts and stops at a predetermined sampling period, and the signal processing unit detects at the sampling period Generates a rectangular wave detection signal based on the output signal output from, and samples the level of the detection signal for backup In this mode, if the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, the sampling period becomes the first sampling period and the level of the sampled detection signal is at the previous sampling time. When the detection signal level is the same, the sampling period is a second sampling period longer than the first sampling period.

  In the encoder of the present invention, in the backup mode that is a mode of the encoder corresponding to when the encoder is operated by the power supplied from the battery while the supply of power from the main power supply is stopped, the detection unit has a predetermined sampling period. The signal processing unit generates and detects a rectangular wave detection signal based on the output signal output from the detection unit and samples the level of the detection signal in a sampling cycle. That is, in the present invention, in the backup mode, the power consumption in the detection unit, the signal processing unit, and the like increases intermittently in the sampling period, but is not always large. Therefore, in the present invention, the power consumption of the encoder in the backup mode (that is, the power consumption of the encoder when the power supply from the main power supply is stopped and the encoder is operating with the power supplied from the backup battery) It becomes possible to reduce.

  In the present invention, in the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, the sampling period becomes the first sampling period, and the level of the sampled detection signal is If the level of the detection signal at the previous sampling is the same, the sampling period becomes a second sampling period longer than the first sampling period. That is, in the present invention, in the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, and the rotating body is rotating, the first sampling cycle having a short cycle is used. Then, the detection unit is started and stopped, and the signal processing unit generates a detection signal and samples the level of the detection signal. Therefore, in the present invention, in the backup mode, it is possible to appropriately detect how many rotations of the rotating body from the predetermined origin position by the encoder while reducing the power consumption of the encoder. In the present invention, in the backup mode, when the level of the detection signal sampled is the same as the level of the detection signal at the previous sampling, and it is estimated that the rotating body is not rotating, the cycle is long. In the second sampling period, the detection unit starts and stops, and the signal processing unit generates the detection signal and samples the level of the detection signal, so that the power consumption of the encoder in the backup mode is effectively reduced. It becomes possible to make it.

  In the present invention, the encoder includes two detection units that output output signals that are 90 ° out of phase, and in the backup mode, one of the two detection units is started and stopped at the sampling period. In addition, the other detection unit of the two detection units may start and stop when the level of the detection signal generated based on the output signal output from one detection unit is inverted. preferable. With this configuration, it is possible to effectively reduce the power consumption of the other detection unit or the like in the backup mode, and as a result, it is possible to more effectively reduce the power consumption of the encoder in the backup mode. Become.

  In the present invention, the encoder includes two detectors that output output signals that are 90 ° out of phase, where the first sampling period is t1 (seconds) and the maximum rotational speed of the rotating body is N (rpm). , T1 preferably satisfy the relationship of t1 <(N / 60) / (90/360). If comprised in this way, it will become possible to detect appropriately how many rotations a rotary body is rotating from the predetermined origin position with an encoder.

  In the present invention, the detection unit is a Hall element, and the signal processing unit includes a comparator to which an output signal output from the Hall element is input, and a CPU (Central Processing Unit) connected to the output side of the comparator. The Hall element and the comparator are preferably supplied with power directly from the CPU. With this configuration, there is no need to provide a power supply IC for supplying power to the Hall element and a power supply IC for supplying power to the comparator. Therefore, the configuration of the encoder can be simplified.

  In the present invention, when the mode of the encoder corresponding to the operation of the encoder by the power supplied from the main power supply is set to the normal operation mode, the encoder is controlled by the upper control unit which is the control unit of the upper device on which the encoder is mounted. When the control command signal is not input to the encoder for a predetermined time, it is preferable to shift from the normal operation mode to the backup mode. When the control command signal from the host control unit is not input to the encoder for a predetermined time, some trouble occurs in the main power supply and the host control unit does not intentionally output the control command signal, or the host device It is presumed that the main power supply has stopped due to some trouble such as being stopped or the cable connecting the encoder and the host device being disconnected. Therefore, with this configuration, the encoder is operated by the power supplied from the battery without providing the encoder with a means for detecting whether or not power is supplied from the main power source to the encoder. By estimation, the encoder can be shifted to the backup mode. That is, the encoder can be shifted to the backup mode while simplifying the configuration of the encoder.

  In order to solve the above problems, the encoder control method of the present invention is an encoder control method in which a main power source and a backup battery are connected and the absolute position of the rotation angle of the rotating body can be detected. Then, when the power supply from the main power supply is stopped and the encoder mode corresponding to the operation of the encoder by the power supplied from the battery is the backup mode, the rotating body is rotated at a predetermined sampling period in the backup mode. Activates and stops the detection unit for detecting how many rotations of the rotation point from the predetermined origin position, generates a rectangular wave detection signal based on the output signal output from the detection unit, and In addition to sampling the level, in the backup mode, the level of the sampled detection signal is If the detection signal level is different from that at the sampling time, the sampling period is the first sampling period, and if the sampled detection signal level is the same as the detection signal level at the previous sampling, the sampling period is The second sampling period is longer than the first sampling period.

  In the encoder control method of the present invention, in the backup mode, the detection unit is started and stopped at a predetermined sampling period, a rectangular wave detection signal is generated based on the output signal output from the detection unit, and the detection is performed. Sampling the signal level. That is, in the present invention, in the backup mode, the power consumption in the detection operation for detecting how many times the rotating body is rotating from the predetermined origin position increases intermittently, but is not always large. Therefore, in the present invention, the power consumption of the encoder in the backup mode (that is, the power consumption of the encoder when the power supply from the main power supply is stopped and the encoder is operating with the power supplied from the backup battery) It becomes possible to reduce.

  In the present invention, in the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, the sampling period is set to the first sampling period and the sampled detection signal When the level is the same as the level of the detection signal at the previous sampling, the sampling period is set to the second sampling period longer than the first sampling period. That is, in the present invention, in the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, and the rotating body is rotating, the first sampling cycle having a short cycle is used. Then, the detection unit is started and stopped, a detection signal is generated, and the level of the detection signal is sampled. Therefore, in the present invention, in the backup mode, it is possible to appropriately detect how many rotations of the rotating body from the predetermined origin position by the encoder while reducing the power consumption of the encoder. In the present invention, in the backup mode, when the level of the detection signal sampled is the same as the level of the detection signal at the previous sampling, and it is estimated that the rotating body is not rotating, the cycle is long. In the second sampling cycle, the detection unit is started and stopped, and the detection signal is generated and the level of the detection signal is sampled. Therefore, it is possible to effectively reduce the power consumption of the encoder in the backup mode. become.

  In the encoder control method of the present invention, when the encoder mode corresponding to the operation of the encoder by the power supplied from the main power supply is set to the normal operation mode, the upper control unit which is a control unit of the upper device in which the encoder is mounted When the control command signal is not input to the encoder for a predetermined time, it is preferable to shift the encoder from the normal operation mode to the backup mode. When the control command signal from the host control unit is not input to the encoder for a predetermined time, some trouble occurs in the main power supply and the host control unit does not intentionally output the control command signal, or the host device Since it is presumed that the main power supply has stopped due to some failure such as the cable being stopped or the cable connecting the encoder and the host device being disconnected, Even if the encoder is not provided with means for detecting whether or not power is being supplied from the power supply to the encoder, it is estimated that the encoder is operating with the power supplied from the battery, and the encoder is put into backup mode. It becomes possible to migrate. That is, the encoder can be shifted to the backup mode while simplifying the configuration of the encoder.

  As described above, according to the present invention, it is possible to reduce the power consumption of the encoder when the power supply from the main power supply is stopped and the encoder is operating with the power supplied from the backup battery. Further, by using the encoder control method of the present invention, it is possible to reduce the power consumption of the encoder when the power supply from the main power supply is stopped and the encoder is operating with the power supplied from the backup battery. It becomes possible.

It is a figure for demonstrating schematic structure of the encoder concerning embodiment of this invention. It is a figure for demonstrating the mechanical schematic structure of the encoder shown in FIG. It is a figure for demonstrating one part schematic structure of the 2nd operation | movement part shown in FIG. It is a figure which shows the detection signal produced | generated by the signal processing part shown in FIG. It is a figure for demonstrating the effect of the encoder shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Encoder configuration)
FIG. 1 is a diagram for explaining a schematic configuration of an encoder 1 according to an embodiment of the present invention. FIG. 2 is a diagram for explaining a mechanical schematic configuration of the encoder 1 shown in FIG. 1. FIG. 3 is a diagram for explaining a schematic configuration of a part of the second operation unit 14 shown in FIG. FIG. 4 is a diagram illustrating detection signals S1 and S2 generated by the signal processing unit 18 illustrated in FIG.

  The encoder 1 of this embodiment is an absolute encoder (absolute value encoder) for detecting the absolute position of the rotation angle (rotation position) of the rotating body. The encoder 1 is attached to, for example, a servo motor that is a host device, and is used to detect an absolute position of a rotation angle of a rotor that is a rotating body. The encoder 1 is connected to a host controller 2 that is a servo motor controller. The encoder 1 receives the control command signal of the encoder 1 from the upper control unit 2, and the encoder 1 returns a response signal to the control command to the upper control unit 2.

  The encoder 1 is connected to a main power source 3 and a backup battery 4. Normally, power is supplied from the main power source 3 to the encoder 1, and the encoder 1 is operated by the power supplied from the main power source 3. Further, when the supply of power from the main power supply 3 is stopped for some reason, the encoder 1 is supplied with power from the battery 4, and the encoder 1 operates with the power supplied from the battery 4.

  The encoder 1 is a magnetic encoder. As shown in FIG. 2, the encoder 1 includes, as a mechanical configuration, a sensor magnet 8 that is fixed to a rotating shaft 7 that constitutes a rotor of a servo motor, and a magnetoresistive element 9 that is disposed to face the sensor magnet 8. And two Hall elements 10 and 11.

  The sensor magnet 8 is a permanent magnet formed in a disk shape. On the surface of the sensor magnet 8 facing the magnetoresistive element 9 and the Hall element 10, one N pole and one S pole are formed in the circumferential direction. The magnetoresistive element 9 is arranged so that the center of the sensor magnet 8 and the center of the magnetoresistive element 9 substantially coincide when viewed from the axial direction of the rotating shaft 7. The magnetoresistive element 9 is formed with a magnetoresistive pattern arranged in a direction substantially orthogonal to each other. The two Hall elements 10 and 11 are arranged at positions shifted from each other by 90 ° with respect to the center of the sensor magnet 8 when viewed from the axial direction of the rotating shaft 7.

  The encoder 1 generates position data indicating a rotation angle within a range of one rotation (360 °) of the rotating body (rotor) based on the detection result of the magnetoresistive element 9, and outputs a signal of this position data. To do. Further, the encoder 1 generates multi-rotation data indicating how many times the rotating body is rotating from a predetermined origin position based on the detection results of the Hall elements 10 and 11, and the multi-rotation data signal is generated. Output. The Hall elements 10 and 11 of this embodiment are detection units for detecting how many times the rotating body is rotating from a predetermined origin position.

  The encoder 1 of the present embodiment is a normal operation mode that is a mode corresponding to the operation by the power supplied from the main power supply 3 and the power supplied from the battery 4 while the power supply from the main power supply 3 is stopped. It is possible to switch between three modes: a backup mode that is a mode that corresponds to when operating by the power supply, and a stop mode that is a mode that corresponds to when the power supply from the main power supply 3 and the battery 4 is stopped and the operation is not performed It has become. In the normal operation mode, the encoder 1 detects the absolute position of the rotational position of the rotating body and communicates with the host controller 2. In the backup mode, the encoder 1 generates and holds multi-rotation data. The power consumption of the encoder 1 in the backup mode is smaller than the power consumption of the encoder 1 in the normal operation mode.

  In this embodiment, when the encoder 1 is operating in the normal operation mode, if the control command signal from the host controller 2 is not input to the encoder 1 for a predetermined time, the encoder 1 shifts from the normal operation mode to the backup mode. To do. That is, when the control command signal from the host controller 2 is not input to the encoder 1 for a predetermined time, the trouble occurs in the main power source 3 and the host controller 2 does not intentionally output the control command signal, or Because it is presumed that the main power supply 3 is stopped due to some trouble such as the host device being stopped due to a power failure or the cable connecting the encoder 1 and the host device being disconnected. The encoder 1 shifts from the normal operation mode to the backup mode. For example, when the encoder 1 is operating in the normal operation mode and the control command signal is not input from 1000 to 1500 (microseconds (μsec)) from the host control unit 2, the encoder 1 changes from the normal operation mode to the backup mode. Migrate to Further, when the control command signal from the host control unit 2 is input while the encoder 1 is operating in the backup mode, the encoder 1 shifts from the backup mode to the normal operation mode. Note that switching between the normal operation mode and the backup mode is performed by processing on a microprocessor (MPU, not shown) constituting the encoder 1.

  Moreover, the encoder 1 is provided with the 1st action | operation part 13 and the 2nd action | operation part 14 for detecting the absolute position of the rotation angle of a rotary body, as shown in FIG. The main power supply 3 is connected to the first operating unit 13, and the first operating unit 13 operates in the normal operation mode. The main power supply 3 and the battery 4 are connected to the second operation unit 14 via a diode, a resistor, and the like, and the second operation unit 14 operates in the normal operation mode and the backup mode.

  As shown in FIG. 3, the second operation unit 14 includes the Hall elements 10 and 11 described above. The second operation unit 14 includes comparators 15 and 16 to which output signals from the Hall elements 10 and 11 are input, and a CPU 17 connected to the output side of the comparators 15 and 16. In this embodiment, the comparators 15 and 16 and the CPU 17 constitute a signal processing unit 18 that processes output signals output from the Hall elements 10 and 11 that are detection units. The hall elements 10 and 11 and the comparators 15 and 16 are connected to the CPU 17 without going through the power supply IC, and power is directly supplied to the hall elements 10 and 11 and the comparators 15 and 16 from the CPU 17.

  In the normal operation mode, power is always supplied to the Hall elements 10 and 11 and the comparators 15 and 16. Further, in the normal operation mode, the signal processing unit 18 generates a rectangular wave detection signal S1 (see FIG. 4) based on the output signal output from the Hall element 10, and the output output from the Hall element 11 A rectangular wave detection signal S2 (see FIG. 4) is generated based on the signal. As described above, since the N pole and the S pole are formed in the circumferential direction on the surface of the sensor magnet 8 facing the Hall elements 10 and 11, when the rotating body makes one rotation, Detection signals S1 and S2 for one cycle are generated. Further, as described above, since the Hall elements 10 and 11 are arranged at positions shifted from each other by 90 ° with respect to the center of the sensor magnet 8, the phase of the detection signal S1 and the detection signal are detected as shown in FIG. The phase of S2 is shifted by 90 °.

  In the normal operation mode, the signal processing unit 18 samples the levels of the detection signals S1 and S2 at a predetermined sampling period. Since the phase of the detection signal S1 and the phase of the detection signal S2 are shifted by 90 °, the low level and the high level of the detection signal S1 and the low level and the high level of the detection signal S2 are detected during one rotation of the rotating body. As a combination, four combinations are generated. That is, as shown in FIG. 4, four regions “area1” to “area4” are generated every 90 ° during one rotation of the rotating body. The signal processing unit 18 generates multi-rotation data by sequentially detecting the four areas “area1” to “area4”.

  On the other hand, in the backup mode, the Hall element 10 and the comparator 15 are activated and stopped at a predetermined sampling period. Further, the signal processing unit 18 generates the detection signal S1 based on the output signal output from the Hall element 10 in this sampling cycle, and samples the level of the detection signal S1. In the backup mode, when the level of the sampled detection signal S1 is different from the level of the detection signal S1 at the time of the previous sampling, since the rotating body is rotating, the subsequent sampling cycle is a second sampling cycle described later. The first sampling period T1 (see FIG. 5) is shorter than T2 (see FIG. 5). In the backup mode, if the level of the sampled detection signal S2 is the same as the level of the detection signal S1 at the previous sampling, it is estimated that the rotating body is not rotating. The second sampling period T2 is longer than the first sampling period T1.

When the first sampling period T1 is t1 (seconds) and the maximum rotational speed of the rotating body is N (rpm), the signal processing unit 18 sequentially detects four areas “area1” to “area4” that occur every 90 °. Thus, t1 satisfies the following relationship so that appropriate multi-rotation data can be generated.
t1 <(N / 60) / (90/360)
For example, if N is 6000 (rpm), t1 is less than 2.5 (milliseconds (msec)), so t1 is set to 2 (msec). When the second sampling period T2 is t2 (seconds), t2 is set in consideration of acceleration when the rotating body in the stationary state shifts to the rotating state. For example, if t1 is 2 (msec), t2 is set to 5 (msec).

  In the backup mode, the Hall element 11 and the comparator 16 are activated and stopped when the level of the detection signal S1 sampled in the first sampling period T1 or the second sampling period T2 is inverted. Further, the signal processing unit 18 generates the detection signal S2 based on the output signal output from the Hall element 11 at this time, and samples the level of the detection signal S2.

  The operations of the Hall elements 10 and 11 and the signal processing unit 18 in the backup mode are executed based on a control command from the above-described MPU (not shown) constituting the encoder 1.

(Main effects of this form)
As described above, in this embodiment, in the backup mode, which is the mode of the encoder 1 corresponding to when the encoder 1 is operated by the power supplied from the battery 4 while the supply of power from the main power supply 3 is stopped, The Hall element 10 and the comparator 15 are started and stopped at a predetermined sampling period, and the signal processing unit 18 generates the detection signal S1 based on the output signal output from the Hall element 10 at this sampling period, The level of the detection signal S1 is sampled. Further, in the backup mode, when the level of the detection signal S1 sampled at a predetermined sampling period is inverted, the Hall element 11 and the comparator 16 are activated and stopped, and the signal processing unit 18 at this time The detection signal S2 is generated based on the output signal output from the signal 11, and the level of the detection signal S2 is sampled.

  Therefore, in this embodiment, in the backup mode, the current consumption of the Hall elements 10, 11 and the signal processing unit 18 and the like is intermittently increased in the first sampling period T1 or the second sampling period T2, and as a result, FIG. As shown, the current consumption of the encoder 1 increases intermittently but is not always large. For example, in the first sampling period T1 or the second sampling period T2, the current consumption of the encoder 1 is temporarily several milliamperes (mA). In other cases, the encoder 1 is not performing any processing, and the encoder 1 The current consumption of 1 is several microamperes (μA). Therefore, in this embodiment, the power consumption of the encoder 1 in the backup mode (that is, the encoder 1 when the power supply from the main power supply 3 is stopped and the encoder 1 is operating with the power supplied from the backup battery 4) Power consumption) can be reduced.

  In particular, in the present embodiment, in the backup mode, when the level of the detection signal S1 sampled at a predetermined sampling period is inverted, the Hall element 11 and the comparator 16 are activated and stopped, and the signal processing unit 18 Since the detection signal S2 is generated based on the output signal output from the Hall element 11 and the level of the detection signal S2 is sampled, the power consumption of the Hall element 11 and the comparator 16 in the backup mode is effectively reduced. It becomes possible to make it. As a result, in this embodiment, it is possible to effectively reduce the power consumption of the encoder 1 in the backup mode.

  In this embodiment, in the backup mode, when the level of the sampled detection signal S1 is different from the level of the detection signal S1 at the time of the previous sampling, the rotating body is rotating, so the subsequent sampling period is the second sampling period T2. Since the first sampling cycle T1 is shorter and the level of the sampled detection signal S2 is the same as the level of the detection signal S1 at the previous sampling, it is estimated that the rotating body is not rotating. The sampling period becomes the second sampling period T2 which is longer than the first sampling period T1. That is, in this embodiment, when the rotating body is rotating, the subsequent sampling cycle becomes the first sampling period T1, and therefore, in the backup mode, the rotating body is reduced by the encoder 1 while reducing the power consumption of the encoder 1. Thus, it is possible to appropriately detect how many rotations are from a predetermined origin position. Further, in this embodiment, when it is estimated that the rotating body is not rotating, the subsequent sampling cycle becomes the second sampling cycle T2, so that the power consumption of the encoder 1 in the backup mode can be effectively reduced. It becomes possible.

  In this embodiment, when the first sampling period T1 is t1 (seconds) and the maximum rotational speed of the rotating body is N (rpm), t1 satisfies the relationship t1 <(N / 60) / (90/360). ing. Therefore, as described above, the signal processing unit 18 can sequentially detect the four regions “area1” to “area4” that occur every 90 °, and generate appropriate multi-rotation data. Therefore, in this embodiment, the encoder 1 can appropriately detect how many times the rotating body is rotating from the predetermined origin position.

  In this embodiment, the Hall elements 10 and 11 and the comparators 15 and 16 are connected to the CPU 17 without going through the power supply IC, and power is directly supplied to the Hall elements 10 and 11 and the comparators 15 and 16 from the CPU 17. The That is, in this embodiment, the power supply IC for supplying power to the Hall elements 10 and 11 and the comparators 15 and 16 is not provided. Therefore, in this embodiment, the configuration of the encoder 1 can be simplified.

  In this embodiment, when the encoder 1 is operating in the normal operation mode, if the control command signal from the host controller 2 is not input to the encoder 1 for a predetermined time, the encoder 1 shifts from the normal operation mode to the backup mode. To do. In other words, in this embodiment, when the control command signal from the host control unit 2 is not input to the encoder 1 for a predetermined time, a trouble occurs in the main power source 3 and the host control unit 2 intentionally outputs the control command signal. If the main power supply 3 is stopped due to some trouble such as failure or failure of the host device due to a power failure, or disconnection of the cable connecting the encoder 1 and the host device. Since it is estimated, the encoder 1 shifts from the normal operation mode to the backup mode. Therefore, in this embodiment, the encoder 1 is operated by the power supplied from the battery 4 without providing the encoder 1 with a detection circuit for detecting whether or not the power is supplied from the main power source 3 to the encoder 1. Therefore, the encoder 1 can be shifted to the backup mode. That is, in this embodiment, it is possible to shift the encoder 1 to the backup mode while simplifying the configuration of the encoder 1.

(Other embodiments)
The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited to this, and various modifications can be made without departing from the scope of the present invention.

  In the above-described form, in the backup mode, when the level of the detection signal S1 sampled in the first sampling period T1 or the second sampling period T2 is inverted, the Hall element 11 and the comparator 16 are activated and stopped, and the signal The processing unit 18 generates the detection signal S2 based on the output signal output from the Hall element 11 at this time, and samples the level of the detection signal S2. In addition, for example, in the backup mode, similarly to the Hall element 10 and the comparator 15, the Hall element 11 and the comparator 16 are activated and stopped at the first sampling period T1 or the second sampling period T2, and the signal processing unit 18 is activated. In this sampling cycle, the detection signal S2 may be generated based on the output signal output from the Hall element 11, and the level of the detection signal S2 may be sampled.

  In the embodiment described above, the Hall elements 10 and 11 and the comparators 15 and 16 are connected to the CPU 17 without going through the power supply IC. In addition to this, for example, the Hall elements 10 and 11 and the comparators 15 and 16 may be connected to the CPU 17 via a power supply IC.

  In the above-described embodiment, when the encoder 1 is operating in the normal operation mode, if the control command signal from the host control unit 2 is not input to the encoder 1 for a predetermined time, the encoder 1 switches from the normal operation mode to the backup mode. Transition. In addition to this, for example, a detection circuit for detecting whether or not electric power is supplied from the main power supply 3 to the encoder 1 is provided in the encoder 1, and based on the detection result of the detection circuit, the encoder 1 The operation mode may be shifted to the backup mode.

  In the embodiment described above, the encoder 1 is a magnetic encoder. The encoder 1 includes, for example, a light emitting element and a light receiving element, and a slit plate on which a slit that transmits light from the light emitting element to the light receiving element is formed. It may be a photoelectric encoder provided. In addition, the encoder 1 may be an encoder other than a magnetic type or a photoelectric type.

DESCRIPTION OF SYMBOLS 1 Encoder 2 High-order control part 3 Main power supply 4 Battery 10 Hall element (detection part, one detection part)
11 Hall element (detector, other detector)
15 Comparator 16 Comparator 17 CPU
18 Signal processing unit S1 detection signal S2 detection signal T1 first sampling period (sampling period)
T2 Second sampling period (sampling period)

Claims (7)

An encoder that is connected to a main power source and a backup battery and can detect the absolute position of the rotation angle of the rotating body,
A detection unit for detecting how many rotations the rotating body rotates from a predetermined origin position, and a signal processing unit for processing an output signal output from the detection unit,
When the supply of power from the main power supply is stopped and the encoder mode corresponding to the operation of the encoder by the power supplied from the battery is a backup mode,
In the backup mode, the detection unit starts and stops at a predetermined sampling period, and the signal processing unit generates a rectangular wave detection signal based on the output signal output from the detection unit at the sampling period. Generating and sampling the level of the detection signal;
In the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, the sampling period becomes the first sampling period, and the level of the sampled detection signal Is the same as the level of the detection signal at the previous sampling, the sampling period is a second sampling period longer than the first sampling period. Including two detection units that output the output signals that are 90 ° out of phase;
In the backup mode, one of the two detection units is activated and stopped at the sampling period, and the other detection unit of the two detection units is one of the two detection units. The encoder according to claim 1, wherein the encoder is started and stopped when a level of the detection signal generated based on the output signal output from the detection unit is inverted. Including two detection units that output the output signals that are 90 ° out of phase;
When the first sampling period is t1 (seconds) and the maximum rotational speed of the rotating body is N (rpm), t1 is
t1 <(N / 60) / (90/360)
The encoder according to claim 1, wherein the relationship is satisfied. The detection unit is a Hall element,
The signal processing unit includes a comparator to which the output signal output from the Hall element is input, and a CPU (Central Processing Unit) connected to the output side of the comparator,
The encoder according to any one of claims 1 to 3, wherein the hall element and the comparator are directly supplied with electric power from the CPU. When the mode of the encoder corresponding to the operation of the encoder by the power supplied from the main power supply is a normal operation mode,
When the control command signal from the host control unit that is the control unit of the host device on which the encoder is mounted is not input to the encoder for a predetermined time, the normal operation mode is shifted to the backup mode. The encoder according to any one of claims 1 to 4. An encoder control method in which a main power source and a backup battery are connected and an absolute position of a rotation angle of a rotating body can be detected,
When the supply of power from the main power supply is stopped and the encoder mode corresponding to the operation of the encoder by the power supplied from the battery is a backup mode,
In the backup mode, a detection unit for detecting how many rotations the rotating body is rotating from a predetermined origin position is started and stopped at a predetermined sampling period, and the output signal output from the detection unit is Generating a rectangular wave-shaped detection signal based on the sampling level and sampling the level of the detection signal;
In the backup mode, when the level of the sampled detection signal is different from the level of the detection signal at the previous sampling, the sampling period is set as the first sampling period, and the level of the sampled detection signal Is the same as the level of the detection signal at the previous sampling, the sampling period is set to a second sampling period longer than the first sampling period. When the mode of the encoder corresponding to the operation of the encoder by the power supplied from the main power supply is a normal operation mode,
Causing the encoder to shift from the normal operation mode to the backup mode when a control command signal from a host controller that is a controller of a host device in which the encoder is mounted is not input to the encoder for a predetermined time. An encoder control method according to claim 6.

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