JP2020180929A - Rotation sensor - Google Patents

Abstract

To provide a rotation sensor with which it is possible to properly diagnose a fault in accordance with the rotation speed of a rotor.SOLUTION: A first normal/reverse determination unit 124 accepts input of a position signal S3 and a phase signal S4 via a first path 132 from a detection unit 103, and determines whether a gear 200 rotates normally or in reverse on the basis of the position and phase signals via the first path 132. A second normal/reverse determination unit 125 accepts input of a position signal and a phase signal via a second path 133 from the detection unit 103, and determines whether the gear 200 rotates normally or in reverse on the basis of the position and phase signals via the second path 133. A comparison unit 126 accepts input of a determination result from the first normal/reverse determination unit 124 and accepts input of a determination result from the second normal/reverse determination unit 125, and compares the determination result of the first normal/reverse determination unit 124 with the determination result of the second normal/reverse determination unit 125, thereby diagnosing a fault for each monitoring cycle. The comparison unit 126 sets the monitoring cycle to be the same as the edge interval of the position signal S3.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rotation sensor.

Conventionally, for example, Patent Document 1 has proposed a rotation sensor including two detection units that output a detection signal according to the rotation of a rotating body. The two detection signals output from each detection unit have a phase. The rotation sensor binarizes the two detection signals and determines the forward or reverse rotation of the rotating body based on the phases of the two binarized signals.

Japanese Unexamined Patent Publication No. 2005-249488

In the above-mentioned conventional technique, the binarized signals of each path can be compared by configuring a dual system that duplicates the two detection signals output from each detection unit. The binarized signals of the two paths are compared, for example, at regular monitoring cycles. When the comparison results are different, the comparison results can be notified to the outside as a failure determination.

Here, it is conceivable to set a long monitoring cycle. However, when the rotation speed of the rotating body is high, the rotation of the rotating body advances before the monitoring cycle ends. As a result, the determination of the failure diagnosis is delayed, and the real-time property of the failure diagnosis is impaired.

On the other hand, it is conceivable to set the monitoring cycle short. However, when the rotation speed of the rotating body is slow, the monitoring cycle ends before the failure diagnosis determination is completed, so that even if a failure occurs, it is determined that there is no failure. Therefore, the failure detection range is limited.

In this way, if the monitoring cycle is fixed at a constant level, it becomes difficult to perform a failure diagnosis corresponding to the rotation speed of the rotating body.

In view of the above points, an object of the present invention is to provide a rotation sensor capable of performing an appropriate failure diagnosis according to the rotation speed of a rotating body.

In order to achieve the above object, in the invention according to claim 1, the rotation sensor includes a detection unit (103) and a determination circuit unit (104).

The detection unit is arranged with a predetermined gap with respect to the outer peripheral portion of the rotating body (200) in which the rotation position information is periodically provided on the outer peripheral portion (201) at regular intervals. The detection unit uses the main signal of the waveform corresponding to the rotation position information of the rotating body and the main signal based on the magnetic change received from the outer peripheral portion as the rotation position of the rotating body changes due to the rotation of the rotating body. On the other hand, sub-signals with a waveform having a phase are generated.

The forward / reverse determination circuit unit has a binarization threshold value for binarizing the main signal and the sub signal, and inputs the main signal and the sub signal from the detection unit. The forward / reverse determination circuit unit compares the main signal with the binarization threshold value to generate a position signal obtained by binarizing the main signal, and compares the sub signal with the binarization threshold value to binarize the sub signal. Generates a binarized phase signal. The forward / reverse determination circuit unit determines whether the rotation direction of the rotating body is forward rotation or reverse rotation based on the position signal and the phase signal.

The forward / reverse determination circuit unit includes a first forward / reverse determination unit (124), a second forward / reverse determination unit (125), and a diagnosis unit (126, 127). The first determination unit inputs a position signal and a phase signal from the detection unit via the first path (132), and determines forward or reverse rotation of the rotating body based on the position signal and the phase signal via the first path. To do. The second determination unit inputs a position signal and a phase signal from the detection unit via a second path (133) different from the first path, and the rotating body is based on the position signal and the phase signal via the second path. Judge forward or reverse rotation.

The diagnosis unit inputs the judgment result from the first judgment unit, inputs the judgment result from the second judgment unit, and compares the judgment result of the first judgment unit with the judgment result of the second judgment unit to monitor the monitoring cycle. Diagnose the failure every time. Then, the diagnostic unit increases or decreases the monitoring cycle in accordance with the increase or decrease of the edge interval of the position signal or the edge interval of the phase signal.

According to this, the monitoring cycle is set shorter as the edge interval of the position signal or the edge interval of the phase signal decreases, that is, as the rotation speed of the rotating body increases. Therefore, it is possible to avoid a delay in the determination of the failure diagnosis due to the long monitoring cycle, so that the real-time property of the failure diagnosis is not impaired. Further, the monitoring cycle is set longer as the edge spacing of the position signal or the edge spacing of the phase signal increases, that is, the slower the rotation speed of the rotating body. Therefore, it is possible to prevent the monitoring cycle from ending before the failure diagnosis determination is completed due to the short monitoring cycle. Therefore, an appropriate failure diagnosis can be performed according to the rotation speed of the rotating body.

The reference numerals in parentheses of each means described in this column and the scope of claims indicate the correspondence with the specific means described in the embodiments described later.

It is a figure which showed the arrangement relation of the rotation sensor which concerns on one Embodiment of this invention, and a gear type rotor. It is a figure which showed the circuit structure of the rotation sensor shown in FIG. It is a figure for demonstrating operation of a rotation sensor. It is a figure which showed the judgment condition of the rotation direction of a gear. It is a figure which showed the fluctuation of a monitoring cycle.

Hereinafter, one embodiment will be described with reference to the drawings. The rotation sensor according to the present invention detects, for example, the rotation of a gear incorporated in a crank angle determination device or a transmission of an internal combustion engine of a vehicle. As shown in FIG. 1, the rotation sensor 100 is arranged so as to face the outer peripheral portion 201 of the gear 200. The gear 200 is a gear-shaped rotating body.

The outer peripheral portion 201 of the gear 200 is provided with convex portions 202 and concave portions 203 alternately in the rotational direction. The convex portion 202 is a tooth. The convex portion 202 and the concave portion 203 indicate the rotation position information of the gear 200 in the rotation direction. The convex portion 202 and the concave portion 203 have a constant width in the rotation direction. The convex portion 202 and the concave portion 203 are periodically provided at regular intervals in the rotation direction. That is, the constant interval is a cycle of repeating the rotation position in the rotation direction of the gear 200. That is, the rotation position information is periodically provided on the outer peripheral portion 201 of the gear 200 at regular intervals. Note that FIG. 1 shows a part of the outer peripheral portion 201 of the gear 200 developed in a straight line. The same applies to FIG. 2 below.

The rotation sensor 100 includes a case (not shown) formed by resin molding a resin material such as PPS. The case has a tip portion on the gear 200 side, a fixing portion fixed to a peripheral mechanism, and a connector portion to which a harness is connected. A sensing portion is provided inside the tip portion.

Further, the case is fixed to the peripheral mechanism via the flange portion so that the tip portion has a predetermined gap with respect to the convex portion 202 of the gear 200. Therefore, the gear 200 moves with respect to the rotation sensor 100. The rotation sensor 100 includes a bias magnet 101 and a sensor chip 102 as sensing portions.

The bias magnet 101 increases the detection sensitivity of the magnetic field of the sensor chip 102 by a certain amount by applying a bias magnetic field to the sensor chip 102. The bias magnet 101 has a cylindrical shape. A sensor chip 102 is arranged in the hollow portion of the bias magnet 101.

The sensor chip 102 is configured as a semiconductor chip. The sensor chip 102 includes a detection unit 103. The detection unit 103 employs a magnetic detection method using a magnetoresistive element. The detection unit 103 detects the magnetic change received from the outer peripheral portion 201 as the rotation position of the gear 200 changes due to the rotation of the gear 200. Specifically, the detection unit 103 outputs a signal corresponding to the position of the unevenness as the gear 200 rotates. The detection unit 103 is arranged with a predetermined gap with respect to the outer peripheral portion 201 of the gear 200 in the gap direction. That is, the gap direction is the radial direction of the gear 200.

The rotation sensor 100 is configured as an ASIC. Specifically, as shown in FIGS. 1 and 2, the rotation sensor 100 includes a detection unit 103 and a determination circuit unit 104.

The detection unit 103 includes a first magnetic detection element 105, a second magnetic detection element 106, a third magnetic detection element 107, a first operational amplifier 108, a second operational amplifier 109, a third operational amplifier 110, and a fourth operational amplifier 111.

Each of the magnetic detection elements 105 to 107 is configured as a pair of magnetoresistive elements whose resistance value changes with the rotation of the gear 200.

The magnetoresistive element pair is configured as a half-bridge circuit. Specifically, as shown in FIG. 2, the first magnetic detection element 105 is composed of two magnetoresistive portions connected in series between a power supply (Vcc) and a ground (GND). The two magnetoresistive portions are magnetoresistive elements 112 and 113.

The first magnetic detection element 105 detects a change in the resistance value when each of the magnetoresistive elements 112 and 113 is affected by a magnetic field as the gear 200 rotates. Further, the first magnetic detection element 105 outputs the midpoint voltage A of the midpoint 114 of each magnetoresistive element 112 and 113 based on the change in the resistance value.

The second and third magnetic detection elements 106 and 107 have the same configuration as the first magnetic detection element 105. The second magnetic detection element 106 is composed of two magnetic detection elements 115 and 116. The second magnetic detection element 106 outputs the midpoint voltage B of the midpoints 117 of the magnetic detection elements 115 and 116. The third magnetic detection element 107 is composed of two magnetoresistive elements 118 and 119. The third magnetic detection element 107 outputs the midpoint voltage C of the midpoint 120 of each magnetoresistive element 118 and 119.

The first to fourth operational amplifiers 108 to 111 are differential amplifiers. The first operational amplifier 108 outputs AB as a calculation result. The second operational amplifier 109 outputs BC as a calculation result.

The third operational amplifier 110 inputs AB from the first operational amplifier 108 and inputs BC from the second operational amplifier 109. Then, the third operational amplifier 110 calculates {-(AB)-(BC)} and outputs the calculation result as the main signal S1 (= 2B-AC) to the determination circuit unit 104. For example, the main signal S1 is a signal having a waveform in which the amplitude is maximum or minimum at the concave portion 203, the convex portion 202, and the edge portion of the gear 200.

The fourth operational amplifier 111 is a differential amplifier configured to calculate AC and output the result as S2. The signal of S2 is a sub-signal having a waveform having a phase with respect to the main signal S1. For example, the sub signal S2 is a signal having a waveform in which the amplitude is maximum at the center of the convex portion 202 of the gear 200 in the rotational direction and the amplitude is minimum at the center of the concave portion 203 in the rotational direction.

As described above, the detection unit 103 is configured to generate and acquire the main signal S1 and the sub signal S2 from the outputs of the magnetic detection elements 105 to 107.

Further, the rotation sensor 100 includes a determination circuit unit 104 that generates an output signal according to the rotation mode of the gear 200 detected by the detection unit 103. The determination circuit unit 104 may be formed on the sensor chip 102 described above, or may be formed on another semiconductor chip (not shown).

The determination circuit unit 104 generates a position signal obtained by binarizing the main signal, compares the sub signal with the binarization threshold, and generates a phase signal obtained by binarizing the phase signal, thereby generating the position signal and the phase signal. It is determined whether the rotation direction of the gear 200 is forward rotation or reverse rotation based on the above.

Specifically, the determination circuit unit 104 includes a threshold generation unit 121, a first comparator 122, a second comparator 123, a first forward / reverse determination unit 124, a second forward / reverse determination unit 125, a comparison unit 126, and a confirmation / clear unit. It includes 127 and an output control unit 128.

The threshold generation unit 121 is composed of two resistors 129 and 130 connected in series between the power supply (Vcc) and the ground (GND). The potential of the midpoint 131 of the resistors 129 and 130 is set as the binarization threshold. The binarization threshold is used as a threshold for binarizing the main signal S1 and the sub signal S2.

The first comparator 122 inputs the main signal S1 from the third operational amplifier 110 of the detection unit 103, inputs the binarization threshold value from the threshold generation unit 121, compares the main signal S1 with the binarization threshold value, and compares the main signal. A position signal S3 obtained by binarizing S1 is generated.

The second comparator 123 inputs the sub signal S2 from the fourth operational amplifier 111 of the detection unit 103, inputs the binarization threshold value from the threshold generation unit 121, compares the sub signal S2 with the binarization threshold value, and compares the sub signal. A phase signal obtained by binarizing S2 is generated.

The first forward / reverse determination unit 124 inputs the position signal S3 from the third operational amplifier 110 and the phase signal S4 from the fourth operational amplifier 111 via the first path 132. The first forward / reverse determination unit 124 determines forward rotation or reverse rotation of the gear 200 based on the position signal S3 and the phase signal S4 via the first path 132. Further, the first forward / reverse determination unit 124 outputs the position signal S3 to the output control unit 128.

The second forward / reverse determination unit 125 inputs the position signal S3 from the third operational amplifier 110 and the sub signal S2 from the fourth operational amplifier 111 via the second path 133 different from the first path 132. The first path 132 and the second path 133 are signal paths duplicated for inputting the outputs of the comparators 122 and 123 to the forward / reverse determination units 124 and 125, respectively. The second forward / reverse determination unit 125 determines forward / reverse rotation of the gear 200 based on the position signal S3 and the sub signal S2 via the second path 133.

The comparison unit 126 diagnoses a failure of the forward / reverse determination logic for each monitoring cycle by comparing the determination result of the first forward / reverse determination unit 124 with the determination result of the second forward / reverse determination unit 125. In this way, the determination results based on the duplicated logic, that is, the dual system are compared, and if the comparison results are different, the comparison unit 126 determines that the failure has occurred. The comparison unit 126 outputs the comparison result to the confirmation / clear unit 127.

The monitoring cycle is not a fixed cycle but a variable cycle. The comparison unit 126 increases or decreases the monitoring cycle in accordance with the increase or decrease of the edge interval of the position signal S3 or the edge interval of the phase signal S4. That is, the comparison unit 126 sets a long monitoring cycle when the rotation speed of the gear 200 is high, and sets a short monitoring cycle when the rotation speed is slow. Specifically, the comparison unit 126 sets the monitoring cycle to be the same as the edge interval of the position signal S3.

The confirmation / clear unit 127 determines or clears the failure according to the comparison result of the comparison unit 126. The confirmation / clear unit 127 sets “0” when a normal comparison result is input from the comparison unit 126. The confirmation / clear unit 127 sets “1” when the comparison result of the failure is input from the comparison unit 126, and determines the failure when “1” is counted three times in a row, for example. How many times "1" is continuously counted may be appropriately set.

For example, when "0" is set after setting "1", the confirmation / clear unit 127 clears the setting of "1" indicating a failure. The confirmation / clear unit 127 outputs failure confirmation or clear information to the output control unit 128.

The output control unit 128 inputs the position signal S3 from the first determination unit, and also inputs the failure confirmation or clear information from the confirmation / clear unit 127. Then, when the confirmation / clear unit 127 does not input the confirmation of the failure, the output control unit 128 outputs the position signal S3 as a rotation signal to an external device (not shown) via the output terminal 134 (Vout).

The determination circuit unit 104 repeats reception, output, standby, and the like of the position signal S3 or the phase signal S4 according to a series of sequences. The above is the overall configuration of the rotation sensor 100. The rotation sensor 100 includes a power supply terminal 135 (Vcc) and a ground terminal 136 (GND) connected to an external device. The rotation sensor 100 operates by supplying power from an external device via the power supply terminal 135 and the ground terminal 136.

Next, the operation of the rotation sensor 100 will be described. First, when the gear 200 rotates, as shown in FIG. 3, the detection unit 103 acquires the main signal S1 and the sub signal S2 based on the change in the gap between the detection unit 103 and the outer peripheral portion 201 of the gear 200. ..

The main signal S1 is a signal having a waveform that exceeds the binarization threshold at the center of the convex portion 202 of the gear 200 in the rotation direction. On the other hand, the sub signal S2 is a signal having a phase with respect to the main signal S1, specifically, a waveform having the maximum amplitude at the center of the convex portion 202 of the gear 200 in the rotation direction.

Then, the main signal S1 acquired by the detection unit 103 is compared with the binarization threshold value by the first comparator 122 of the determination circuit unit 104. When the signal amplitude of the main signal S1 is larger than the binarization threshold, for example, Hi is generated, and when the signal amplitude of the main signal S1 is smaller than the binarization threshold, for example, the Lo position signal S3 is generated by the first comparator 122.

The sub-signal S2 acquired by the detection unit 103 is compared with the binarization threshold value by the second comparator 123 of the determination circuit unit 104. When the amplitude of the sub signal S2 is larger than the binarization threshold, for example, Hi is generated, and when the amplitude of the sub signal S2 is smaller than the binarization threshold, for example, the Lo phase signal S4 is generated by the second comparator 123.

As described above, the main signal S1, the sub signal S2, the position signal S3, and the phase signal S4 are generated at any time as the gear 200 rotates, and the position signal S3 and the phase signal S4 are the forward / reverse determination units 124 and 125, respectively. Is entered in.

The forward / reverse determination units 124 and 125 determine whether the rotation direction of the gear 200 is forward rotation or reverse rotation based on the position signal S3 phase signal S4.

First, when the rotation direction of the gear 200 is normal, the amplitude of the main signal S1 becomes smaller than the binarization threshold before and after the time point T10. Therefore, the position signal S3 changes from Hi to Lo. Further, since the signal amplitude of the sub signal S2 is larger than the binarization threshold value, the binarized phase signal S4 becomes Hi. Therefore, each of the forward / reverse determination units 124 and 125 satisfies both the position signal falling from Hi to Lo and the phase signal being Hi, so that the gear 200 is determined to be in forward rotation. To.

On the other hand, when the rotation direction of the gear 200 is reversed, the amplitude of the main signal S1 becomes larger than the binarization threshold before and after the time point T10. Therefore, the position signal S3 changes from Lo to Hi. Further, since the signal amplitude of the sub signal S2 is larger than the binarization threshold value, the binarized phase signal S4 becomes Hi. Therefore, each of the forward / reverse determination units 124 and 125 satisfies both the position signal S3 rising from Lo to Hi and the phase signal S4 being Hi, so that it is determined that the gear 200 is reversed. To.

The above determination is the same before and after the time point T11. That is, the forward / reverse determination units 124 and 125 determine the rotation direction of the gear 200 depending on whether or not the conditions shown in FIG. 4 are satisfied.

Subsequently, the comparison unit 126 compares the determination results of the forward / reverse determination units 124 and 125. As shown in FIG. 5, when the determination results of the forward / reverse determination units 124 and 125 match in one monitoring cycle from the time point T20 to the time point T21, “0” is set in the confirmation / clear unit 127. To. Here, one monitoring cycle is the edge interval of the signal from the falling edge of the position signal S3 to the falling edge. Further, the output control unit 128 outputs the pulse-shaped position signal S3 input from the first forward / reverse determination unit 124 to the external device as a rotation signal.

For example, it is assumed that an abnormality such as a timer failure occurs in any of the forward / reverse determination units 124 and 125 after the time point T21. Therefore, in one monitoring cycle from the time point T21 to the time point T22, the determination results of the forward / reverse determination units 124 and 125 do not match. Then, "1" indicating a failure is set in the confirmation / clear unit 127. In FIG. 5, the case where the comparison results do not match is represented by diagonal lines. Even in each monitoring cycle from the time point T22 to the time point T23 and from the time point T23 to the time point T24, the judgment results of the forward / reverse judgment units 124 and 125 are shown. Will not match, and "1" indicating a failure will be set in the confirmation / clear unit 127. As a result, in the confirmation / clear unit 127, "1" indicating a failure is counted three times in a row, so that the failure is confirmed. Then, the confirmation / clear unit 127 outputs the failure confirmation information to the output control unit 128.

The output control unit 128 performs a process of fixing the pulse-shaped position signal S3 input from the first forward / reverse determination unit 124 to the Hi level. That is, the output control unit 128 outputs the diagnostic information to the external device. The rotation signal is output as PWM output from the output control unit 128 before the failure is confirmed, that is, until the time point T23.

Similarly, the determination results are inconsistent from the time point T24 to the time point T27. Therefore, since the "1" indicating the failure is counted three times in a row by the time point T27, the output of the diagnostic information is continued. That is, the output of the rotation signal is stopped.

Then, after the time point T27, the rotation speed of the gear 200 becomes slow. The section from time point T27 to time point T28 is longer than the section from time point T26 to time point T27. That is, the edge interval of the position signal S3 becomes long, and the monitoring cycle in the comparison unit 126 also becomes long.

Similarly, in the section from the time point T28 to the time point T29, the rotation speed of the gear 200 is further slower than in the previous section. Along with this, the monitoring cycle in the comparison unit 126 also becomes longer in conjunction with the change in the edge interval of the position signal S3.

For example, it is assumed that after the time point T29, the abnormality is resolved and the normal state is restored. As a result, the determination results of the forward / reverse determination units 124 and 125 match in one monitoring cycle from the time point T29 to the time point T30. In the confirmation / clear unit 127, "0" indicating normality is set, and the abnormality is cleared. Therefore, the pulse-shaped position signal S3 is output from the output control unit 128 to the external device as a rotation signal.

In the above, it has been explained that the rotation speed of the gear 200 changes at the time of abnormality and the monitoring cycle also changes, but the monitoring cycle also changes when the rotation speed of the gear 200 changes at the normal time.

As described above, the smaller the edge spacing of the position signal S3, that is, the faster the rotation speed of the gear 200, the shorter the monitoring cycle is set in conjunction with the edge spacing of the position signal S3. Therefore, it is possible to avoid a delay in the determination of failure diagnosis due to the monitoring cycle being longer than the edge interval of the position signal S3. Therefore, the real-time performance of the failure diagnosis is not impaired.

Further, as the edge spacing of the position signal S3 increases, that is, as the rotation speed of the gear 200 becomes slower, the monitoring cycle is set longer in conjunction with the edge spacing of the position signal S3. Therefore, it is possible to prevent the monitoring cycle from ending before the failure diagnosis determination is completed because the monitoring cycle is shorter than the edge interval of the position signal S3.

Therefore, for a configuration in which the monitoring cycle is fixed to a constant value, an appropriate failure diagnosis can be performed according to the rotation speed of the gear 200.

Regarding the correspondence between the description of the present embodiment and the description of the claims, the comparison unit 126 and the confirmation / clear unit 127 correspond to the “diagnosis unit” of the claims. Further, the gear 200 corresponds to the "rotating body" in the claims.

As a modification, the comparison unit 126 may set the monitoring cycle to be the same as the edge spacing of the phase signal S4.

As another modification, the comparison unit 126 does not set the monitoring cycle to be exactly the same as the edge spacing of the position signal S3 and the phase signal S4, but increases the edge spacing of the position signal S3 or the edge spacing of the phase signal S4. The monitoring cycle may be increased or decreased in accordance with the decrease.

(Other embodiments)
The configuration of the rotation sensor 100 shown in each of the above embodiments is an example, and the configuration is not limited to the configuration shown above, and other configurations capable of realizing the present invention can be used. For example, the rotating body is not limited to the gear 200, and may be a magnetizing rotor. The magnetizing rotor is a disk-shaped rotating body in which the first magnetic pole, which is the north pole, and the second magnetic pole, which is the south pole, are magnetized alternately in the circumferential direction of the outer peripheral portion. In the case of a magnetizing rotor, for example, the main signal is the signal having the maximum or minimum amplitude at the boundary of each magnetic pole, and the sub signal is the signal having the maximum or minimum amplitude at the center in the width direction in the rotational direction of each magnetic pole.

The detection unit 103 includes three magnetic detection elements 105 to 107, but is not limited to this configuration. For example, the detection unit 103 may include five elements. In this case, sub-signals can be generated using the outputs of the fourth and fifth elements. That is, the detection unit 103 may have a configuration capable of generating a main signal and a sub signal.

103 Detection unit 104 Judgment circuit unit 124 1st forward / reverse judgment unit 125 2nd forward / reverse judgment unit 126 Comparison unit 127 Confirmation / clear unit 132 1st route 133 2nd route

Claims (3)

Rotational position information is periodically provided on the outer peripheral portion (201) at regular intervals, and is arranged with a predetermined gap with respect to the outer peripheral portion of the rotating body (200). Based on the magnetic change received from the outer peripheral portion as the rotation position changes, the main signal of the waveform corresponding to the rotation position information of the rotating body and the waveform having a phase with respect to the main signal. A detection unit (103) that generates sub-signals and
It has a binarization threshold for binarizing the main signal and the sub signal, inputs the main signal and the sub signal from the detection unit, and compares the main signal with the binarization threshold. The main signal is binarized to generate a position signal, and the sub signal is compared with the binarization threshold to generate a phase signal obtained by binarizing the sub signal to generate the position signal and the phase. A determination circuit unit (104) that determines whether the rotation direction of the rotating body is forward rotation or reverse rotation based on a signal, and
Including
The determination circuit unit
The position signal and the phase signal are input from the detection unit via the first path (132), and forward or reverse rotation of the rotating body is performed based on the position signal and the phase signal via the first path. The first forward / reverse determination unit (124) for determination and
The position signal and the phase signal are input from the detection unit via a second path (133) different from the first path, and the rotation is based on the position signal and the phase signal via the second path. The second forward / reverse determination unit (125) that determines the forward / reverse rotation of the body,
The judgment result is input from the first forward / reverse judgment unit, and the judgment result is input from the second forward / reverse judgment unit. The judgment result of the first forward / reverse judgment unit and the judgment result of the second forward / reverse judgment unit are input. The diagnostic unit (126, 127), which diagnoses failures in each monitoring cycle by comparing with
With
The diagnostic unit is a rotation sensor that increases or decreases the monitoring cycle in accordance with an increase or decrease in the edge interval of the position signal or the edge interval of the phase signal. The rotation sensor according to claim 1, wherein the diagnostic unit sets the monitoring cycle to be the same as the edge spacing of the position signal. The rotation sensor according to claim 1, wherein the diagnostic unit sets the monitoring cycle to be the same as the edge interval of the phase signal.

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