JP2000213959A - Position detecting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a position detecting device requiring no adjustment of a mechanical fitting angle by generating phase-variable absolute data. SOLUTION: This device is provided with a position detection section arranged in the prescribed mechanical layout relation to a moving object, a means receiving the output signal from the position detection section and generating a fixed absolute signal indicating the position of the moving object, a writable memory means 45 storing the difference data between the position corresponding to a specific pattern in the fixed absolute signal and a specific position determined based on the mechanical layout relation, and a means 51 generating the phase-variable absolute data practically drifted with the fixed absolute signal by the phase corresponding to the difference data read out from the memory means 45.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a position detecting device using a fixed absolute signal.

[0002]

2. Description of the Related Art Some position detecting devices attached to various devices such as motors must generate signals in synchronization with a specific phase due to mechanical characteristics of the various devices. In such a case, the positioning is adjusted so that the rise of the output waveform matches the mechanical arrangement relationship or is shifted by a predetermined angle. Such alignment is essentially unrelated to the encoder which is a position detector, but is performed from the viewpoint of improving rotation efficiency and the like.
The positional relationship between the motor unit and the encoder unit is adjusted so that one rising point of the U, V, and W phase magnetic pole detection signals has a phase difference of 30 degrees with respect to the zero cross point of the induced voltage. And so on.

More specifically, as shown in FIG. 14, by rotating a rotor magnet 1 in a motor section M, an induced voltage as shown in FIG. Vu is output, and the screw position of the hollow shaft 4 of the encoder unit E with respect to the shaft 3 of the rotor magnet 1 is adjusted, so that the magnetic pole detection signal from the Hall element 6 disposed opposite to the magnetic pole detection magnet 5 is output. The phase difference is, for example, 30 degrees with respect to the above-described induced voltage Vu.

In the case of the absolute encoder shown in FIG. 16, a single marking line (not shown) extending in the radial direction is inserted into the bottom surface of the encoder case 6, and a screw hole of the hollow shaft 7 is formed. The mounting positional relationship of the multi-track absolute glass disk 8 is adjusted so that a specific output state is obtained when 7a faces the marking line.

[0005]

However, since the adjustment work in such a conventional device involves matching the mechanical mounting angle with the electrical signal logic, strict position adjustment is required. This is extremely time-consuming, and reduces the productivity of the position detecting device itself and the workability of mounting the position detecting device. In addition, when the motor is reduced in diameter or multi-pole, a slight displacement of the mounting position causes the arrangement of the magnetized magnets to be not at equal intervals, resulting in a non-uniform duty of each magnetic pole, a misalignment of the Hall element on the circuit board, and the like. As a result, the phase difference between the magnetic pole detection signals is shifted, which causes problems such as lowering of motor performance.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a position detecting device capable of extremely easily performing an attaching operation and improving productivity.

[0007]

In order to achieve the above object, according to the present invention, there is provided a detecting unit arranged in a predetermined mechanical arrangement relation with respect to a moving object, and receiving an output signal from the position detecting unit. Means for generating a fixed absolute signal representing the position of the moving object, and storing difference data between a position corresponding to a specific pattern in the fixed absolute signal and a specific position determined based on the mechanical arrangement relationship. Writable storage means, and means for generating phase-variable absolute data in which the fixed absolute signal is substantially shifted by a phase corresponding to the difference data read from the storage means.

According to the invention, the use of the variable phase absolute data makes it unnecessary to adjust the position when mounting the position detecting device.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. First, as shown in FIG. 1, the basic structure of a motor 11 with an encoder will be described. A magnetic drum 13 for detecting a rotational position of an encoder and a magnetic drum for detecting a magnetic pole position are provided on an output shaft 12 of the motor. A disk 14 is integrally mounted, and an MR element 15 is arranged so as to face the outer peripheral magnetized surface of the rotational position detecting magnetic drum 13. Two Hall elements 16 and 17 having an electrical phase difference of 90 degrees are arranged on the encoder substrate 18 so as to face each other in the axial direction.

The rotational position detection signals Va, Vb, Vz from the MR element 15 and the magnetic pole position detection signals Vha, Vhb from the Hall elements 17, 18 are used in actual use.
A predetermined signal processing is performed, and the signal is transmitted and output from the output terminal to various control devices. In the present embodiment, the mounting relationship between the encoder unit and the motor unit in the motor with encoder 11 is measured, and the phase is measured. In order to adjust the relationship, the above-mentioned output terminal is connected to the COM port 21a of the personal computer 21 for setting angle difference data by a cable.
That is, the encoder-equipped motor 11 is connected so as to constitute a detection target.

On the other hand, a coil 22 extending from a stator coil end of the motor section as the object to be detected is connected to a constant current source 24 via a relay 23, and the relay 23 and the constant current source 24,
A motor lock command signal is issued from the personal computer 21, and a predetermined adjustment operation as described later is performed.

The output shaft 25 on the opposite side of the motor unit has:
An output shaft of a drive motor 27 is connected via a coupling 26, and a rotation drive command signal from the personal computer 21 is given to a drive device 28 of the drive motor 27 so that the drive motor 27 rotates. The motor section as the object to be detected is thereby rotated.

On the other hand, the encoder substrate 18 has a structure shown in FIG.
Is provided. In this transmission-side processing circuit, the rotational position detection signals Vz, Va, and Vb output from the MR element 15 are transmitted through the waveform shaping circuits 31z, 31a, and 31b, respectively.
The signals are converted into phase, A-phase, and B-phase rectangular wave signals and output to the line driver 32. The A-phase and B-phase rectangular wave signals are sent to the gate array 50 side and input to a phase variable absolute counter 51 described later.

Further, the above-described Hall elements 16, 17
The two-phase substantially sinusoidal magnetic pole position detection signals Vha and Vhb having a 90-degree phase difference
The analog signal is sent to the microcomputer 40 as it is through a and 33b, and the signal is converted through the A / D converter 42 while being selectively switched by the multiplexer 41. The A / D conversion data is transmitted to the R
The data is sent to the OM table 43, the address of the table is specified, and the table data is extracted from the ROM table 43.
A fixed absolute data signal (interpolation data signal) having a predetermined resolution for one rotation is obtained in the same manner as in the invention described in Japanese Patent No. 9914.

In the ROM table 43 in the present embodiment, as shown in FIG. 3, the magnetic pole position detection signals Vha and Vhb from the two Hall elements 16 and 17 described above.
, And has decomposition data obtained by solving one rotation in 1024 steps from 0 to 1023.

Returning to FIG. 2, the above-described external personal computer 21
Is supplied to the SCI 44 in the microcomputer 40 by serial communication of the RxD line and the TxD line, the angle difference data is written into the nonvolatile memory (EEPROM) 45 as a new set value. The set value of the angle difference data is updated. The angle difference data in the nonvolatile memory 45 is sent from the phase variable absolute counter 51 provided in the gate array 50 to the UVW generation circuit 52 through the bus, and the following phase shift control operation is performed.

In the apparatus according to the present embodiment, the encoder is attached to the motor so that the encoder has an arbitrary mechanical relationship without performing strict alignment.
Before shipment from the factory, angle difference data between the motor unit and the encoder unit is measured, and the measured data is stored in the nonvolatile memory 45.
Written in. Hereinafter, a procedure for measuring the angle difference data will be described.

First, as shown in FIG. 1 described above, when the motor lock command is issued from the personal computer 21, the V phase and the W phase are short-circuited in the relay 23 and the constant current source 24 Supplies a DC current to the motor unit. Then, the rotor magnet of the motor unit is attracted and stopped at a predetermined rotation position by the electromagnet action, and is positioned at a previously determined position to be in a rotation locked state.

Next, after the locked state is released by a command from the personal computer 21, the drive motor 27 is driven to rotate in the direction of CCW in FIG.
As a result, the rotation angle θ of the horizontal axis in each figure in FIG. 4 advances rightward in the figure, and the two-phase Hall outputs Vha and Vhb shown in FIG. 1 from 0 to 1023 as shown in FIG.
In addition to obtaining fixed absolute data having a sawtooth shape in 024 steps, an induced (back electromotive) voltage of the U phase as shown in FIG.

At this time, assuming that the rotation position of the above-described motor lock is θl in FIG.
The phase variable absolute counter 51 is reset so as to correspond to 1 and the counter value in the phase variable absolute counter 51 is incremented from there. That is, the output of the phase variable absolute counter 51 is set to “0” at the lock position θl, and then increases as shown in FIG.

At the same time, each of the magnetic pole position detection signals Vha and Vhb from the two Hall elements 16 and 17 is sampled at regular intervals by software in the microcomputer 40, and the ROM table 43 is corresponded to the sampled values. The interpolation data in is referred to. Then, the position where the fixed absolute data, which is the output of the ROM table 43, becomes "0", that is, FIG.
At the position of θz in (b), the counter value ΔD of the phase variable absolute counter 51 is obtained.

Next, the counter value .DELTA.D in the phase variable absolute counter 51 is subtracted from the fixed absolute data value "1024" from the ROM table 43 corresponding to the 360-degree position of one rotation, thereby producing the output difference .DELTA.Dp (1024). -ΔD) is obtained. From the output difference ΔDp thus obtained, the ROM table 4
3, the angle difference data Δθp is obtained by referring to the fixed absolute data, and such angle difference data ΔDp or Δθp is written in the nonvolatile memory 45. Note that the value of ΔD is measured within one rotation of the drive motor 27 because the position of θz described above always appears within one rotation.

On the other hand, the shaft rotation position when the power is turned on after shipment from the factory is different from each other. Therefore, each time the power is turned on, the following initialization is performed, the angle difference data ΔDp or Δθp in the nonvolatile memory 45 is called by the software of the microcomputer 40, and the output of the ROM table 43 is used as described above. Calculation is performed using the current angle read from certain fixed absolute data, whereby the variable phase absolute counter 51 is preset and the phase is adjusted.

For example, when the power is turned on, FIG.
Of the non-volatile memory 45
Is read out from the memory, and is temporarily stored in the RAM. While the multiplexer 41 is operated by the software of the microcomputer 40, each of the magnetic pole position detection signals Vha and Vhb from the two Hall elements 16 and 17 is signal-converted through the A / D converter 42, and the digital conversion data Vha (θ
0) and Vhb (θ0) are obtained.

The digital conversion data Vh
When the address of the ROM table 43 is specified via the bus by a (θ0) and Vhb (θ0), the fixed absolute data at that time is extracted as table data DROM (θ0). Since the fixed absolute data and the variable phase absolute data are shifted by the angle difference data Δθp, that is, the counter value is shifted by ΔDp, DROM (θ0) −ΔDp is calculated in the CPU.

The calculated value is preset in the variable phase absolute counter 51, whereby the phase is adjusted. That is, the sawtooth output from the variable phase absolute counter 51 shown in FIG. 4G is output according to the designated phase position by the above-described preset, and the output from the variable phase absolute counter 51 is changed. Of the sawtooth waveform of the threshold (Uth0, Wth) corresponding to each phase of U, W, V every 60 degrees
th60, Vth120, Uth180, Wth24
0, Vth300), the U, V, and W phase outputs as shown in FIGS. (D), (e), and (f) are automatically output according to the rotation of the shaft. Becomes

As described above, in the present embodiment, a desired output signal can be obtained even if the encoder unit is mounted without performing strict positioning with respect to the motor unit.

In the encoder of the embodiment shown in FIG. 5, the screw hole 7a of the hollow shaft 7 is screwed to a rotating shaft of a motor (not shown), and the hollow shaft 7 is The multi-track absolute glass disk 8 is adhesively fixed at an arbitrary position. For this multi-track absolute glass disk 8, a photodiode array 8b
Are arranged face-to-face, and the gray code detection signal from each photodiode array 8b is sent to the gray code binary converter 61 in the gate array 60 through the waveform shaping circuit 8c.

The fixed absolute signal, which is a conversion output from the gray code binary converter 61 of the gate array 60, is output to a subtractor 62 and is also applied to a binary absolute data register 63, from which the Z-phase signal is output. The comparison value is given to the register 64.

The subtractor 62 has a microcomputer 80
Angle difference data called out from the non-volatile memory 81 is provided through the angle difference register 65, and as described later, variable phase absolute data is obtained by subtraction from the fixed absolute data.

On the other hand, in the angle difference measuring device according to the present embodiment, as shown in FIG. 6, an encoder E as an object to be adjusted is connected to the output shaft 71a of the drive motor 71, and A flat portion 71b is formed on the output shaft 71a of the drive motor 71 so as to correspond to the encoder set screw Ea.
2 are installed. For the plane mirror 72,
The inspection light from the laser light source 73 is configured to be input, and the light receiver 7 is configured to receive the reflected light.
4 are arranged. Further, the screw detection signal emitted from the light receiver 74 is input into the microcomputer 80 via the personal computer 75.

At this time, when the drive motor 71 is rotated at a constant speed, the above-mentioned fixed absolute signal in the gray code binary converter 61 has a sawtooth waveform as shown in FIG. As shown in FIG. 3B, when the above-described screw detection signal rises at a certain angle (time) θl, the absolute data ΔDp at that time is read, and the ΔDp is detected as angle data, and the angle difference is detected. By writing to the register 65, a variable phase absolute signal as shown in FIG. The above angle difference data ΔDp
Is stored in the non-volatile memory 81 and written to the angle difference register 65 every time the power is turned on.

Returning to FIG. 5, the variable phase absolute signal thus obtained by the subtractor 92 is output as a multi-bit signal through the binary gray code converter 66, and the Z-phase comparison value register 6
The Z-phase is output via the comparator 67 based on the command signal from the control unit 4. The Z-phase comparison value register 6
4 is written with a value calculated from the absolute output pattern for which the Z phase is to be set to high.

At this time, as shown in FIG. 8, the outputs from the gray code binary converter 61 and the angle difference register 65 are transmitted through the parallel / serial converter 68, and are transmitted to the receiving side in the above-described embodiment. Subtractor 62
Similar functions and effects can be obtained by providing the following configuration.

On the other hand, in the embodiment shown in FIGS. 9 and 10, the same components as those in the embodiment shown in FIG. The difference is that the two-phase rotational position detection signals Va and Vb output from the MR element 15 are taken into the multiplexer 41 of the microcomputer 40, the Z-phase signal is applied to the phase variable absolute counter 51, and The point is that a fine AB generation unit 53 is provided in the gate array 50.

Further, as shown in FIG. 10, an initialization preset register 51a similar to that of the above-described embodiment is provided in a phase variable absolute counter 51 arranged in the gate array 50. In addition to the above, the Z-phase automatic preset register 5
1b, and a Z-phase signal is input to the Z-phase automatic preset register 51b.

In this embodiment, it is assumed that the following conditions are set. First, it is assumed that three pairs of N and S poles of the rotor magnet of the motor unit are provided, and the magnetic pole position detection signals Vha and Vhb are also provided for three cycles per rotation. Further, the rotation position detection signals Va and Vb are set to 250 cycles per rotation, the output from the waveform shaping circuits 31a and 31b is multiplied by 4, and the counter value in the phase variable absolute counter 51 becomes 10 from 0 to 999.
00 count. Therefore, one cycle of the fixed absolute signals Vha and Vhb and one cycle of the U-phase induced voltage correspond to 1000/3 (= 333.3) in the counter value of the phase variable absolute counter 51.

First, in the embodiment according to FIG. 2 described above, the two-phase rotational position detection signals Vha,
Vhb is introduced only once at the time of position measurement before shipment from the factory and after power-on, and is not used together with the ROM table 43 thereafter. Therefore, in the present embodiment, Vh at the time of power-on at the time of on-site use after shipment from the factory.
After the use of the A / Vhb, these two-phase rotational position detection signals Va and Vb are also introduced during operation as an encoder, and the A / D converter 42 and the RO
Fine position data within one cycle of Va and Vb is obtained using the M table 43. The fine position data is sent to and output from the fine AB generation unit 53 in the gate array 50, whereby the extremely fine A phase and B
A phase is obtained.

Next, the fixed absolute signal shown in FIG. 11B generated based on the two-phase Hall element signal shown in FIG. 11A is indicated by a dashed line due to factors such as the magnet arrangement. It can deviate from the ideal line as shown by the solid line. In that case, for example, the actual phase angle θ0 is recognized as being shifted like θ0 ′. Therefore, first, the phase difference between the U-phase induced voltage shown in FIG. 9C and the Z-phase rising point shown in FIG. Then, the angle difference data ΔDc between the phase angle when the Z phase rises and the lock position θl in the embodiment of FIG. 2 described above is written in the nonvolatile memory 45, and is based on the angle difference data ΔDc. The phase correction is further performed so that the above-described error is strictly corrected.

That is, when the power is turned on, FIG.
Assuming that the rotation position is θ0 in FIG.
While the multiplexer 41 is operated by the software, the magnetic pole position detection signals Vha and Vhb from the two Hall elements 16 and 17 are respectively converted by the A / D converter 4.
2 and converted into digital converted data Vha
(Θ0) and Vhb (θ0) are obtained. Then, these digital conversion data Vha (θ0), Vhb (θ0)
As a result, the address of the ROM table 43 is specified via the bus, and the fixed absolute data at that time is extracted as the table data DROM (θ0). However, due to the error described above,
θ0 ′.

Next, since the fixed absolute data and the phase variable absolute data are shifted by Δθp ′, ie, the counter value is ΔDp ′, by the angle difference data, [DROM (θ0) / 1024] × 1000/3. −ΔDp ′ is calculated in the CPU. In addition, the above (1/1024)
× 1000/3 is a coefficient for matching the ratio between the fixed absolute data and the variable phase absolute counter.

Then, the calculated value is written into the preset register 51a of the phase variable absolute counter 51, whereby the phase is adjusted as shown by the one-dot chain line in FIG. The respective U, V, and W phases are output. However, the U, V, and W phase outputs shown in (e) deviate from the original accurate (d) output based on the above-described error. When such a deviation is large, the following correction is performed by using the Z phase.

That is, for example, a value such as the angle difference data ΔDc as shown in FIG. 12 is written in the Z-phase automatic preset register 51b provided in the phase variable absolute counter 51 of the gate array 50. If so, when the Z-phase signal goes high, the value of the phase variable absolute counter 51 moves as indicated by the thick solid line.

Since the Z phase is different from the fixed absolute data only once in one rotation, the reproducibility is remarkably good. Therefore, the value of the phase variable absolute counter 51 corrected as described above is Extremely high precision is obtained, and characteristics such as motor efficiency are improved. It should be noted that when the next Z phase comes, since the correction has already been made, it moves on the same straight line, and the operation does not change whether or not the correction is made.

The angle difference data ΔDc is obtained by resetting the value of the phase variable absolute counter 51 to “0” at the phase angle θl when the motor is locked, when the Z-phase signal becomes high. The counter value of the phase variable absolute counter 51 is read and written in the nonvolatile memory 45.

The variable phase absolute counter 5
For example, the A and B phases whose resolution is improved by multiplying them, that is, the Am phase and the Bm phase, may be input to 1.
Further, the encoder output (Z, A,
B, U, V, W) may be either a parallel output or a serial output.

Further, the threshold values used for generating the U, V, and W phases from the phase variable absolute data may be obtained by calculation especially when the number of change points increases, but in that case, If the calculation circuit shown in FIG. 13 is used, it can be easily obtained simply by using a simple adder, shift, or the like.

That is, as shown in FIG.
On the basis of the output signals from the period-1 register 91 and the 120-degree register 92, the division of 1/2 is performed by right shift 93.
By doubling the multiplication by the left shift 94 and arranging the adders 95 thereon, satisfactory results as shown in Table 1 below were obtained.

[0049]

[Table 1] Table 1 shows an ideal value when 1000 counts are performed in the case of three periods, a result obtained by the calculation circuit shown in FIG. 13, and a difference between them. The difference is extremely small and is within a sufficiently usable range. I understand that there is.

In each of the embodiments described above, the present invention is applied to the detector of the rotation angle. However, the present invention can be similarly applied to a linear position detector.

Further, in the above-described embodiment, the phase variable absolute data generating circuit is provided inside the position detector. However, the fixed absolute signal, data obtained by converting the signal into another signal form, and angle difference data are detected by the position detector. Even if it is created inside the device and transmitted to the higher-level control device, and the variable phase absolute data or the three-phase signal of 120-degree phase is created inside the higher-level control device, the mechanical adjustment can be omitted. Operations and effects similar to those of the embodiment described above can be obtained.

Further, in the above-described embodiment, Vha,
An interpolation circuit for obtaining a fixed absolute signal from Vhb and an interpolation circuit for obtaining fine position data from Va and Vb are represented by A
Although the / D converter and the ROM table are used, an interpolation circuit of another system can be used.

Further, in the above-described embodiment, the phase of the variable phase absolute data is changed by using the angle difference data. However, pulse waveforms such as Z phase, U, V, and W phases are used as outputs. For the purpose of performing this operation, the phase of the variable phase absolute counter is fixed or an absolute counter without the phase variable function is used, and the Z, U, V, and W phase creation thresholds to be compared with the counter value are set as follows.
Even if the configuration is changed based on the angle difference data, the operation and effect of omitting the mechanical adjustment of the present invention can be similarly obtained.

[0054]

As described above, according to the present invention, by generating the phase variable absolute data, it is not necessary to adjust the mechanical mounting angle, and the productivity of the position detecting device can be greatly increased. Can be improved. Further, even if the accuracy of the fixed absolute signal is not good due to a reduction in diameter or the like, a highly accurate output can be obtained by correcting using the Z phase.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of a device for measuring and writing phase difference data in a position detection device according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of a position detection device according to an embodiment of the present invention.

FIG. 3 is a schematic diagram showing an example of ROM table data used in the device of FIG.

FIG. 4 is a chart showing a phase correction operation by the device of FIG. 2;

FIG. 5 is a block diagram illustrating a configuration of a position detection device according to another embodiment of the present invention.

6 is a block diagram showing a configuration example of a device for measuring and writing phase difference data by the device of FIG. 5;

FIG. 7 is a chart showing a phase correction operation by the device of FIG. 5;

FIG. 8 is a block diagram showing a configuration of a position detection device according to still another embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a position detection device according to still another embodiment of the present invention.

FIG. 10 is a block diagram showing a main part of the apparatus of FIG. 9;

FIG. 11 is a chart showing a phase correcting operation by the devices of FIGS. 9 and 10;

FIG. 12 is an enlarged chart showing a main part of a phase correction operation by the devices of FIGS. 9 and 10;

FIG. 13 is a block diagram showing an example of a threshold value calculation circuit used in the device of the present invention.

FIG. 14 is an external perspective explanatory view showing a mounted and adjusted state of a general encoder device.

FIG. 15 is a diagram showing a phase relationship at the time of mounting and adjusting the general encoder device in FIG.

FIG. 16 is an explanatory side view showing a mounted / adjusted state of another type of encoder device.

[Explanation of symbols]

 Reference Signs List 11 Motor with encoder 15 MR element 16, 17 Hall element 18 Encoder board 21 PC for setting angle difference data 24 Constant current source 27 Drive motor 40 Microcomputer 43 ROM table 45 Non-volatile memory (EEPROM) 50 Gate array 51 Phase variable absolute counter 51 Phase variable absolute counter 52 UVW generation circuit 8 Multi-track absolute glass disk 60 Gate array 61 Gray code binary converter 62 Subtractor 80 Microcomputer 81 Non-volatile memory 65 Angle difference register 72 Planar mirror 51a Initializing preset register 51b Z-phase automatic preset register 91 Period-1 register 92 120 degree register 93 Right shift 94 Left shift

 ──────────────────────────────────────────────────続 き Continued from the front page F term (reference) 2F063 AA35 DA05 DD04 DD06 DD08 EA03 GA52 GA72 JA04 KA02 KA03 KA08 LA03 2F069 AA83 FF01 GG06 GG07 GG59 HH12 HH15 NN21 2F077 AA38 CC02 NN02 NN04 NN19 Q15 NN19 Q15 RR03 RR15 TT42 TT62 TT72

Claims (6)

[Claims] A detection unit arranged in a predetermined mechanical arrangement relation with respect to a moving object; and a means for receiving an output signal from the position detection unit and generating a fixed absolute signal indicating a position of the moving object. , Writable storage means for storing difference data between a position corresponding to a specific pattern in the fixed absolute signal and a specific position determined based on the mechanical arrangement relationship, and the fixed absolute signal, Means for generating phase-variable absolute data substantially shifted by a phase corresponding to the difference data read from the storage means. 2. The position detecting device according to claim 1, wherein said phase variable absolute data has a phase of 120 degrees.
A position detecting device comprising means for generating a phase output signal. 3. The position detecting device according to claim 1, wherein an interpolation circuit for generating a fixed absolute signal from a two-phase sine wave signal having a 90-degree phase and a two-phase sine wave signal having a shorter 90-degree phase having a shorter period. A position detecting device characterized by sharing an interpolation circuit for generating high-resolution position data. 4. The position detecting device according to claim 1, further comprising means for presetting the phase variable absolute data by a signal of one pulse per rotation. 5. A detecting unit arranged in a predetermined mechanical arrangement relation with respect to a moving object, and means for receiving a signal output from the position detecting unit and generating a fixed absolute signal indicating the position of the moving object. Writable storage means for storing difference data between a position corresponding to a specific pattern in the fixed absolute signal and a specific position determined based on the mechanical arrangement relationship; An up / down counter having a rectangular wave as input, a means for comparing a counter value of the up / down counter with a changeable threshold value to generate a three-phase output signal having a phase of 120 degrees, Change according to the data
Means for varying the rising and falling positions of the 0-degree three-phase output signal. 6. The position detecting device according to claim 2, wherein a threshold value for generating a three-phase output signal having a phase of 120 degrees corresponds to a period of -1 in the three-phase output signal having a phase of 120 degrees. And a value corresponding to 1/6 or 1/3 of the period of the three-phase output signal having a phase of 120 degrees.