JP6226811B2 - Multi-turn encoder - Google Patents

Description

  The present invention relates to a multi-rotation encoder that detects a rotation direction, a rotation speed, and a rotation angle of a rotating body in a motor or the like.

  In recent years, multi-rotation encoders are used for position control in various robots and machine tools. This multi-rotation encoder includes two detectors: an angle detector that detects a rotation angle within one rotation and a multi-rotation detector that detects the number of rotations. When the reference point of the angle detector (position where the detection angle becomes 0 °) and the reference point of the multi-rotation detector (change point of the multi-rotation data) are deviated, as shown in FIG. In this case, the position data output from the multi-rotation encoder includes an error for one rotation, so both reference points must be matched exactly.

  However, some position data within one rotation detected by the angle detector has a high resolution exceeding 20 bits, and the position of the reference point of the angle detector and the reference point of the multi-rotation detector are accurately positioned. It is very difficult to assemble them together. Furthermore, even if both reference points are accurately matched at the time of assembling, there may be a case in which the reference points are not matched due to displacement of the rotating disk itself or a sensor for detecting the reference point due to a subsequent disturbance.

  Therefore, as shown in FIG. 13, for example, the conventional multi-rotation encoder performs multi-rotation by logical combination of the most significant 2 bits of position data in one rotation generated by the angle detector and the A-phase signal and B-phase signal. By correcting the data, both reference points are matched (for example, see Patent Document 1).

  In addition, as a conventional multi-rotation encoder using another means, a slit pattern of a rotating disk is formed so as to generate a multi-bit GRAY code, and position data within one rotation is preset at the edge (change point) of each GRAY code. However, some of the GRAY codes generate multi-rotation data using GRAY codes (GRAY 6 and GRYA 5) having a relatively long period corresponding to the A-phase / B-phase signal (see, for example, Patent Document 2). In this multi-rotation encoder, the multi-rotation data obtained from the long-period GRAY code is corrected by a correction value obtained from a logical expression combining all the GRAY codes (GRAY1 to GRAY6), so that the reference point of the angle detector And the reference point of the multi-rotation detector were matched.

  Each of these multi-rotation encoders has been devised on the assumption that the deviation between the reference point of the angle detector and the reference point of the multi-rotation detector is about several degrees.

JP-A-6-147814 JP 2002-5691 A

  However, the conventional multi-rotation encoder has a problem that the positions of the reference points of the angle detector and the reference point of the multi-rotation detector cannot be matched when the deviation between the reference point of the multi-rotation detector is 90 ° or more. It was.

  The present invention has been made to solve the above-described problems, and corrects multi-turn data accurately even when the deviation between the reference point of the angle detector and the reference point of the multi-turn detector is 90 ° or more. The purpose is to obtain a multi-rotation encoder capable of matching both reference points.

The multi-rotation encoder according to the present invention uses an angle detector that detects a position within one rotation of the rotating body, and a three-phase signal having a phase difference of 60 ° generated along with the rotation of the rotating body. A multi-rotation detector for detecting the rotational speed as multi-rotation data, a multi-rotation data correcting means for correcting the multi-rotation data from a three-phase signal having a phase difference of 60 ° and position data within one rotation, and an angle detector. Data output means for outputting position data within one rotation and multi-rotation data after correction are provided, and a magnetic wire having a large Barkhausen effect is used as means for generating a three-phase signal with a phase difference of 60 ° The signal processing circuit for generating multi-rotation data is driven by using the pulse generated from the magnetic wire as power, and the multi-rotation data correcting means uses the most significant bits of the position data in one rotation .

The multi-rotation encoder of the present invention detects the number of rotations of the rotating body as multi-rotation data using a three-phase signal having a phase difference of 60 ° generated along with the rotation of the rotating body, and 3 of the phase difference of 60 °. A pulse generated from a magnetic wire using a magnetic wire having a large Barkhausen effect as means for correcting multi-rotation data from a phase signal and position data within one rotation and generating a three-phase signal having a phase difference of 60 ° Is used to drive a signal processing circuit for generating multi-rotation data, and the most significant bits of the position data in one rotation are used for correction of multi-rotation data. Even when the deviation of the reference point of the rotation detector is 90 ° or more, the multi-rotation data can be corrected accurately and the two reference points can be matched.

It is a block diagram which shows the multi-rotation encoder by Embodiment 1 of this invention. It is explanatory drawing which shows the voltage pulse generation means of the multi-rotation encoder by Embodiment 1 of this invention. It is explanatory drawing of the generated pulse with respect to the rotation angle of the magnet of the multi-rotation encoder by Embodiment 1 of this invention. It is explanatory drawing which shows the signal processing table which the multi-rotation data production | generation means of the multi-rotation encoder by Embodiment 1 of this invention uses. It is explanatory drawing which shows the change of each signal with respect to the rotation angle of the multi-rotation encoder by Embodiment 1 of this invention. It is explanatory drawing which shows the signal processing table which the multiple rotation data correction means of the multiple rotation encoder by Embodiment 1 of this invention uses. It is explanatory drawing which shows the multi-rotation data correction example in case the reference point of a multi-rotation detector precedes the reference point of the angle detector of the multi-rotation encoder by Embodiment 1 of this invention by 120 degrees. It is explanatory drawing which shows the example of multi-rotation data correction | amendment in case the reference point of a multi-rotation detector has delayed 120 degrees with respect to the reference point of the angle detector of the multi-rotation encoder by Embodiment 1 of this invention. It is explanatory drawing which shows the voltage pulse generation means of the multi-rotation encoder by Embodiment 2 of this invention. It is explanatory drawing which shows the change of each signal with respect to the rotation angle of the multi-rotation encoder by Embodiment 2 of this invention. It is explanatory drawing which shows the signal processing table which the multiple rotation data correction means of the multiple rotation encoder by Embodiment 2 of this invention uses. It is explanatory drawing of output data when the reference point of an angle detector and the reference point of a multi-rotation detector have shifted | deviated. It is explanatory drawing which shows the conventional multi-rotation data correction method. It is explanatory drawing showing magnetization with respect to the external magnetic field of the soft magnetic body of a magnetic wire.

Embodiment 1 FIG.
1 is a block diagram showing a multi-rotation encoder according to Embodiment 1 of the present invention.
As illustrated, the multi-rotation encoder includes an angle detector 100, a multi-rotation detector 200, a multi-rotation data correction unit 5, and a data output unit 6.

  The angle detector 100 is a device that detects the position of a rotating body within one rotation, and includes a two-phase sine wave signal generating unit 1 and a single rotation position data generating unit 2. The two-phase sine wave signal generating means 1 is a means for generating a two-phase sine wave signal having a specific wavelength according to the rotation of the rotating body. For example, it is composed of a rotating disk formed with an optical or magnetic pattern connected to a motor rotation shaft, and a detection element for reading the optical or magnetic pattern. Here, the two-phase sine wave signal is composed of a set of a sine wave signal and a cosine wave signal having a phase difference of 90 ° with respect to the sine wave signal. Although only one set of two-phase sine wave signals is shown in FIG. 1, a plurality of sets of two-phase sine wave signals having different wavelengths may be generated.

  The position data generating means 2 within one rotation interpolates the two-phase sine wave signal generated by the two-phase sine wave signal generating means 1 at a predetermined time interval, and generates position data subdivided within one wavelength. . As an example of interpolation processing, a sine wave signal and a cosine wave signal are respectively A / D (analog / digital) converted, and the most significant bit (0 or 1) of the sine wave signal and the most significant bit (0 or 1) of the cosine wave signal One of the four quadrants can be limited in combination with 1). In addition, it is possible to limit which of the 45 ° regions obtained by dividing one quadrant into two by the magnitude relationship between the absolute values of the sine value and the cosine value. Further, refer to an arc tangent table for 45 ° stored in advance in a ROM (Read Only Memory) (not shown) using a tangent value or a cotangent value obtained from a sine value and a cosine value as a part of an address. Thus, it can be converted into highly accurate position data.

When a plurality of sets of two-phase sine wave signals having different wavelengths are generated from the two-phase sine wave signal generating means 1, position data is generated by subdividing one wavelength from the two-phase sine wave signals, and these are logically processed. By synthesizing them, position data having higher resolution can be generated. If the ratio of the wavelengths of the two-phase sine wave signals is a power of 2, the composition can be easily performed only by weighting (bit shift) the position data according to the ratio of the wavelengths.
In this way, the position data within one rotation generated by the position data generating means 2 within one rotation becomes position data representing 0 ° to 360 ° with a predetermined resolution.
The signal processing in the position data generating means 2 within one rotation can be realized by software processing using a microcomputer, CPU, etc., but hardware processing by ASIC (Application Specific Integrated Circuit) or FPGA (Field Programmable Gate Array) or the like. But it is feasible.

  The multi-rotation detector 200 is a device that detects the number of rotations of the rotating body as multi-rotation data using a three-phase signal having a phase difference of 60 ° generated along with the rotation of the rotating body. And multi-rotation data generation means 4. In the present embodiment, it is assumed that the multi-rotation detector 200 is a battery-less multi-rotation detector that does not use a backup battery, and that the voltage pulse output from the voltage pulse generation means 3 operates as power. Assumed, a multi-rotation detector using a backup battery may be used.

  The voltage pulse generation means 3 is a means for generating voltage pulses necessary for the multi-rotation data generation means 4 to generate pre-correction multi-rotation data. In the present embodiment, A phase / B phase / C phase pulses are generated. A method of generating the A phase / B phase / C phase pulse will be described with reference to FIG. For example, in the case of a batteryless multi-rotation encoder as shown in International Publication No. 2013-157279, a magnetic wire having a large Barkhausen effect is wound around a detection coil and arranged at 60 ° intervals to rotate the rotating body. Accordingly, the magnet 34 rotates to generate a voltage pulse. That is, by installing a coil containing a magnetic wire around a magnet that rotates together with the rotating body, it is possible to output a pulse of voltage independent of the rotating speed of the rotating body from the coil. The relationship of the magnetization M with respect to the external magnetic field H of the soft magnetic body of the magnetic wire is as shown in FIG. 14, and the voltage pulse varies depending on whether the rotation direction of the rotating body is CW (clockwise) or CCW (counterclockwise). Although the generation position is deviated by the angle φ, positive and negative voltage pulses are generated at every constant rotation in the same rotation direction. Therefore, a multi-rotation detector that does not require a backup battery can be realized by using the power of the voltage pulse.

  In FIG. 2, if the detection coil 31 is for A phase, the detection coil 32 is for B phase, and the detection coil 33 is for C phase, a positive and negative voltage pulse as shown in FIG. 3 is generated. The generation position of each voltage pulse is not the position of 0 °, 60 °, 120 °, 180 °, 240 °, or 300 ° where each detection coil exists, but is shifted by an angle φ / 2 therefrom. When the rotation direction of the magnet is CW, it is shifted by an angle φ / 2 in the plus direction (see FIG. 3A). When the rotation direction of the magnet is CCW, it is shifted by an angle φ / 2 in the minus direction (FIG. 3B). )reference). This is because the magnetization reversal of the magnetic wire does not occur unless the magnetic field reaches a certain strength after the external magnetic field by the magnet is reversed as shown in FIG.

  The multi-rotation data generation means 4 is a signal processing circuit that updates multi-rotation data using A-phase / B-phase / C-phase pulses. In order to update the multi-rotation data, first, it is necessary to generate state signals of A phase / B phase / C phase. The A phase / B phase / C phase state signal can be generated by holding a high level if each detection pulse is a positive sign and holding a low level if the voltage pulse is a negative sign. That is, the A phase / B phase / C phase state signal is a signal representing the sign of the last pulse generated in each wire. In the case of a batteryless multi-rotation detector, the signal processing circuit is driven using the pulse generated by the magnetic wire as power, the sign of the pulse is detected, and the state value (High or Low) is not shown in accordance with the sign. Store in memory.

  Next, multi-rotation data update processing in the multi-rotation data generation means 4 will be described. For example, when changing the multi-rotation data near the reference point of the angle detector of FIG. 2, the multi-rotation is detected when the fall of the B-phase state signal (change from High to Low) is detected while the A-phase state signal is High. If the data is incremented by 1 and the rising of the B phase state signal (change from Low to High) is detected while the A phase state signal is High, the multi-rotation data may be decreased by 1.

  As another method, the multi-rotation data is incremented by 1 when the falling edge of the B phase state signal is detected while the C phase state signal is Low, and the rising edge of the B phase state signal is detected when the C phase state signal is Low. A method of reducing the rotation data by 1 may be used. As another method, when the falling of the B phase state signal is detected while the A phase state signal is High and the C phase state signal is Low, the multi-rotation data is incremented by 1, and the A phase state signal is High and the C phase state signal. When the rising edge of the B-phase state signal is detected in the low state, the multi-rotation data may be reduced by one.

  In the case of a batteryless multi-rotation detector, the signal processing circuit is driven using the pulse generated by the magnetic wire as power, and first, the A-phase / B-phase / C-phase state signal and multi-rotation data stored in the nonvolatile memory Is read. For example, if the A phase / B phase / C phase state signal is (H, H, L), the multi-rotation data is 3, and the pulse generated on the magnetic wire is a B phase negative pulse, this negative pulse causes the B phase state. It is necessary to update the signal from High to Low. Further, since the A-phase state signal is High and the C-phase state signal is Low, it is necessary to increase the multi-rotation data by one. Eventually, the state signal of the A phase / B phase / C phase is updated to (H, L, L), the multi-rotation data is updated to 4, and each is stored in the nonvolatile memory.

  However, in a multi-rotation detector using a magnetic wire having a large Barkhausen effect, the magnetic wire is characterized in that an applied magnetic field slightly exceeding the threshold value is applied to reverse the magnetization and generate a voltage pulse. When the applied magnetic field is reversed due to body reversal or the like, the next generated voltage pulse may decrease. It is known that when the amount of decrease is large, the signal processing circuit for updating and storing the multi-rotation data cannot be driven, and there is a possibility that the detection of the voltage pulse may be lost. When a detection failure occurs, no voltage pulse is generated at the same position, and no voltage pulse is generated until the next voltage pulse generation position.

  When the rotation direction is CW, a negative B-phase pulse should be generated when the magnet reference point is close to the reference point of the angle detector of FIG. However, when the voltage pulse is small and the voltage pulse cannot be detected, the B-phase state signal that should change from High to Low does not change at that position, and the multi-rotation data that should increase by 1 does not change. If nothing is corrected as it is, an abnormal state of the B-phase state signal and the multi-rotation data continues, and some correction is necessary. As a correction method, in addition to the A phase / B phase / C phase state signal at the time when the last pulse is generated, the state signal at the time when the pulse is generated one time before in time series is also used. This prevents a multi-rotation abnormality due to one missing pulse detection. Hereinafter, the state signal at the time when the pulse is finally generated is referred to as the latest state signal, and the state signal at the time when the pulse is generated one time before in time series is referred to as the previous state signal.

  FIG. 4 shows a signal processing table for correction. For example, when the magnet reference point moves from region 6 to region 1 in FIG. 2, a negative B-phase pulse is normally generated, and immediately after that, the rotating body reverses and the magnet reference point returns from region 1 to region 6. The B-phase positive pulse voltage is low, the pulse cannot be detected normally, continues to rotate in the same CCW direction, and the C-phase positive pulse is normally generated when the magnet reference point moves from region 6 to region 5 The operation in this case will be described in order.

  First, when a negative B-phase pulse is normally detected when the magnet reference point moves from the region 6 to the region 1, No. 1 in FIG. 41 or No. As described in 42, the latest state of A phase / B phase / C phase is in region 1 (H, L, L), and the previous state of A phase / B phase / C phase is in region 6 (H, H, L). And the multi-rotation data is incremented by one. When the magnet reference point is located in the region 5 before the region 6, the No. in FIG. 41, when the magnet reference point is located in the area 1 before the area 6, the No. in FIG. 42.

  Next, when the B reference positive pulse cannot be detected when the magnet reference point returns from the region 1 to the region 6, and the C reference positive pulse is detected when the magnet reference point moves from the region 6 to the region 5, No. 4 As described in 8, the latest state of A phase / B phase / C phase is in region 5 (H, H, H), and the previous state of A phase / B phase / C phase is in region 6 (H, H, L). Update the multi-rotation data by one. Since the pulse was not correctly detected when the magnet reference point moved from region 1 to region 6, the latest state of A phase / B phase / C phase, the previous state of A phase / B phase / C phase, and the If the rotation data is not correct, but the pulse can be detected correctly when the magnet reference point moves from region 6 to region 5, then the latest state of A phase / B phase / C phase, the previous state of A phase / B phase / C phase The state and multi-rotation data can be corrected to correct values.

  As described above, in the batteryless multi-rotation detector, even if the voltage of the pulse generated by the magnetic wire is low and the pulse may not be detected normally, the latest state of A phase / B phase / C phase and A phase / B By storing the previous state of phase / C phase, the latest state of A phase / B phase / C phase, the previous state of A phase / B phase / C phase, and multi-rotation data depending on the next generated pulse Can be corrected to the correct value.

  The multi-rotation data generation means 4 is a signal processing circuit that drives the pulse generated by the voltage pulse generation means 3 as power, and needs to operate with ultra-low power consumption. Therefore, the multi-rotation data generation means 4 is generally a hardware such as an ASIC or FPGA. Hardware processing is assumed. However, software processing using a microcomputer or a CPU may be used as long as the power problem can be solved.

  The multi-rotation data correcting means 5 logically corrects the multi-rotation data from the combination of the most significant bits of the position data within one rotation and the latest state signal of A phase / B phase / C phase. Here, as an example, the most significant 2 bits of position data within one rotation are used. FIG. 5 is a diagram showing the values of the respective data when the reference point of the angle detector matches the reference point of the multi-rotation detector.

  If the most significant 2 bits of the position data within one rotation is (0, 0), and the reference points of the angle detector 100 and the multi-rotation detector 200 are completely coincident, the A phase / B phase / C phase The latest state is a state in which the region 1 or the region 2 is correct. When the deviation between the reference points of the angle detector 100 and the multi-rotation detector 200 is 30 ° or less, the latest state of the A phase / B phase / C phase is the region 1 in FIG. It can also be a region 6 shown on the left. Further, when the deviation between both reference points is 60 ° or less, the latest state of the A phase / B phase / C phase becomes the region 3 shown on the right side of the region 2 in addition to the regions 6, 1, and 2. sell. Further, when the deviation between both reference points is 90 ° or less, the latest state of the A phase / B phase / C phase is the region 5 shown on the left side of the region 6 in addition to the region 6, the region 1, the region 2, and the region 3. It can also be. Further, when the deviation between both reference points is 120 ° or less, the latest state of A phase / B phase / C phase is shown on the right side of region 3 in addition to region 5, region 6, region 1, region 2, and region 3. It can also be a region 4 to perform.

  When the deviation between both reference points exceeds 120 °, the latest state of the A phase / B phase / C phase can also be the region 4 illustrated on the left side of the region 5, so the region illustrated on the right side of the region 3 described above 4 is indistinguishable. In other words, it cannot be determined whether the reference point of the multi-rotation detector 200 precedes the region 4 or the region 4 after the reference point of the angle detector 100. However, if the deviation between both reference points is 120 ° or less, the positional relationship between the reference point of the angle detector 100 and the reference point of the multi-rotation detector 200 is uniquely determined. That is, it is possible to determine whether the reference point of the multi-rotation detector 200 is ahead or behind the reference point of the angle detector 100. Therefore, multi-rotation data can be corrected. For example, when the most significant 2 bits of the position data within one rotation are (0, 0) and the latest state of the A phase / B phase / C phase is the region 5 or the region 6, the reference point of the angle detector 100 On the other hand, it can be considered that the reference point of the multi-rotation detector 200 is delayed, and by adding 1 to the multi-rotation data, both reference points can be apparently matched.

  Considering the case where the most significant 2 bits of the position data within one rotation are (0, 1), (1, 0), (1, 1), the multi-rotation data correction table shown in FIG. 6 is obtained. By using this correction table, the multi-rotation data correcting means 5 ensures that both reference points coincide with each other if the deviation between the reference point of the angle detector 100 and the reference point of the multi-rotation detector 200 is 120 ° or less. Can do.

  FIG. 7 is a diagram illustrating a state in which the reference point of the multi-rotation detector 200 is 120 ° ahead of the reference point of the angle detector 100. If multi-rotation correction is performed based on the multi-rotation data correction table shown in FIG. 6, the reference point of the angle detector 100 and the reference point of the multi-rotation detector 200 can be matched. On the other hand, FIG. 8 is a diagram illustrating a state in which the reference point of the multi-rotation detector 200 is delayed by 120 ° with respect to the reference point of the angle detector 100. Also in this case, if the multi-rotation correction is similarly performed based on the multi-rotation data correction table shown in FIG. 6, the reference point of the angle detector 100 and the reference point of the multi-rotation detector 200 can be matched.

The processing of the multi-rotation data correction unit 5 can be realized by software processing using a microcomputer or CPU, but can also be realized by hardware processing such as ASIC or FPGA.
The data output means 6 outputs the position data within one rotation and the corrected multi-rotation data to the host device.

  As described above, according to the multi-rotation encoder of the first embodiment, the angle detector that detects the position of the rotating body within one rotation and the phase difference of 3 generated by the rotation of the rotating body are 3 °. A multi-rotation detector that detects the number of rotations of a rotating body as multi-rotation data using phase signals, and a multi-rotation that corrects multi-rotation data from three-phase signals with a phase difference of 60 ° and position data within one rotation. Since the data correction means and the data output means for outputting the position data within one rotation generated by the angle detector and the corrected multi-rotation data are provided, the reference point of the angle detector and the reference point of the multi-rotation detector Even when the deviation is 90 ° or more, if it is 120 ° or less, the multi-rotation data can be corrected accurately and both reference points can be matched. In addition, since the allowable range of deviation between the two reference points is widened, it is possible to reduce the probability of occurrence of defects due to improvement in yield in the production process and aging after shipment.

  Further, according to the multi-rotation encoder of the first embodiment, a magnetic wire having a large Barkhausen effect is used as means for generating a three-phase signal with a phase difference of 60 °, and a pulse emitted from the magnetic wire is used as a multi-rotation with electric power. Since the signal processing circuit for generating data is driven, the multi-rotation detector can be driven without a battery, and the periodic replacement of the battery becomes unnecessary, and the maintainability can be improved.

Embodiment 2. FIG.
In the first embodiment, as shown in FIG. 2, the change point of the multi-rotation data is set near the reference point of the angle detector 100 (0 ° of the position data within one rotation). The change point may be intentionally shifted from the reference point of the angle detector 100 by a specific angle, which will be described as a second embodiment.

  FIG. 9 shows the positional relationship when the multi-rotation data is updated at 180 ° of the position data within one rotation. As is clear from FIG. 2, the multi-rotation data reference point is set at a position of 180 ° of the position data within one rotation. Further, since the configuration of the multi-rotation encoder on the drawing is the same as that of FIG. 1, the description will be made using the configuration of FIG. In the second embodiment, the configurations and processes of the angle detector 100 and the multi-rotation detector 200 are the same as those in the first embodiment, and the multi-rotation data correction process in the multi-rotation data correcting means 5 is different.

  FIG. 10 shows how each data changes with respect to position data within one rotation. Compared with FIG. 5, it can be seen that the latest state of the A phase / B phase / C phase, the region, and the phase of the multi-rotation data are 180 ° ahead. In this case, the table shown in FIG. 11 may be used as the multi-rotation data correction table used by the multi-rotation data correction means 5.

  Thus, when the position of the detection coil is adjusted so that the multi-rotation data is updated at 180 ° of the position data within one rotation, the correction value of the multi-rotation data is limited to two values of “0” or “−1”. Therefore, it is possible to facilitate the circuit configuration in the case of being realized by a hardware circuit. Note that, if such an effect that the correction value of the multi-rotation data can be limited to two values can be obtained, the angle may not be completely coincident with 180 ° but may be an angle near 180 °. .

  As described above, according to the multi-rotation encoder of the second embodiment, since the change point of the multi-rotation data is 180 ° of the position data within one rotation, the correction value of the multi-rotation data is set to binary. The hardware circuit configuration can be simplified.

  In the present invention, within the scope of the invention, any combination of the embodiments, or any modification of any component in each embodiment, or omission of any component in each embodiment is possible. .

  1 2-phase sine wave signal generating means, 2 position data generating means within one rotation, 3 voltage pulse generating means, 4 multi-rotation data generating means, 5 multi-rotation data correcting means, 6 data output means, 31 A phase pulse detection coil, 32 B-phase pulse detection coil, 33 C-phase pulse detection coil, 34 magnet, 100 angle detector, 200 multi-rotation detector.

Claims (2)

An angle detector for detecting a position within one rotation of the rotating body;
A multi-rotation detector that detects the number of rotations of the rotating body as multi-rotation data using a three-phase signal having a phase difference of 60 ° generated along with the rotation of the rotating body;
Multi-rotation data correction means for correcting the multi-rotation data from the three-phase signal having the phase difference of 60 ° and the position data within the one rotation;
Data output means for outputting position data within one rotation generated by the angle detector and multi-rotation data after correction;
As a means for generating a three-phase signal having a phase difference of 60 °, a magnetic wire having a large Barkhausen effect is used, and a signal processing circuit that generates the multi-rotation data using a pulse emitted from the magnetic wire as power is driven, The multi-rotation data correction means is a multi-rotation encoder that uses the most significant bits of the position data within one rotation . Wherein the changing point of rotation data, multi-rotation encoder according to claim 1 Symbol mounting, characterized in that the 180 ° position data of the one in rotation.

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