JP2003315099A - Multirotation encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce possibility wherein a wrong rotation position is output outside, by reducing influence of induction noise or the like. <P>SOLUTION: In a signal processing circuit 6, on the basis of a signal from an optical type signal detection part 4, an absolute angle position in one rotation of a rotation shaft 1 is obtained by using a data conversion circuit 12, and the number of revolution of the rotation shaft 1 is obtained by using a counter 13. In a signal processing circuit 7, on the basis of a signal from a detection part 5, the number of revolution of the rotation shaft 1 is obtained by using a counter 15. When a main power source is turned on, the detection parts 4, 5 and the circuits 6, 7 are operated by power from the main power source. When the main power source is turned off, operation of the detector 4 and the circuit 6 are stopped, and operation of the detector 5 and the circuit 7 are continued by power from a backup power source. In the case that the main power source is shifted from on to off, a control circuit 24 sets a counted value of a counter 13 as a counted value of the counter 15. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-rotation encoder used for machine tool control, robot control and the like.

[0002]

2. Description of the Related Art As a multi-rotation encoder capable of detecting the absolute position of a rotary shaft over multiple revolutions, a first encoder for detecting a signal for obtaining an absolute angular position within one revolution of the rotary shaft and a rotation speed of the rotary shaft. Of the signal from the signal detection unit, a second signal detection unit that detects a signal for obtaining the rotation speed of the rotating shaft, and the absolute angle position based on the signal from the first signal detection unit. Based on the signal from the first signal processing unit that obtains the rotation speed as a first count value by a predetermined counting operation and the signal from the second signal detection unit, the rotation speed is set to a second rotation speed by a predetermined counting operation. And a second signal processing unit that obtains the count value of the second signal processing unit. In this multi-rotation encoder, when the main power supply is on, the first and second signal detection units and the first and second signal processing units are activated by the power from the main power supply, and when the main power supply is off. The operations of the first signal detection unit and the first signal processing unit are stopped, and the operations of the second signal detection unit and the second signal processing unit are continued by the power from the backup power supply. It Since the operations of the second signal detection unit and the second signal processing unit are continued even when the main power is turned off,
The number of revolutions changed when the main power is turned off can also be detected.

In this conventional multi-rotation encoder, in the main power-on state (original operating state), the first signal detecting section and the first signal processing section are mainly used, and the absolute value obtained from the first signal processing section. The angular position and the number of revolutions are output to the outside, and the second signal detection unit and the second signal processing unit only continue to operate in preparation for the main power-off state. In this conventional multi-rotation encoder, when the main power supply shifts from ON to OFF, the first count value (rotation speed) of the first signal processing unit is reset to zero, and the main power supply OFF state (backup state).
Then, in order to suppress the power consumption, the first signal detection unit and the first signal processing unit are stopped, and only the second signal detection unit and the signal processing unit continue to operate. Then, when the main power is turned on again from the backup state, the second count of the second signal processing unit is set as the first count value to be incremented or decremented next time by the first signal processing unit. The numerical value is set. By such an operation, even if the rotation speed of the rotating shaft changes due to movement of the machine tool, robot, etc. in the backup state due to transportation etc.,
It is possible to properly detect the rotational position of the rotary shaft over multiple revolutions.

Further, in the conventional multi-rotation encoder,
As described above, since the first signal detection unit and the first signal processing unit are mainly used in the main power-on state (original operating state), sufficient shield measures against inductive noise from the motor and the like are taken. In addition, it is configured by using highly reliable components and the like, and further, abnormality detection is performed by adopting various known abnormality detection methods just in case. In the conventional multi-rotation encoder, the second signal processing unit and the second signal processing unit also output an incorrect rotation speed from the second signal processing unit,
Similarly, in order to prevent a situation in which an erroneous rotation speed is output from the first signal processing unit to the outside when the main power supply shifts from OFF to ON, a shield measure is also taken and the reliability is high. Parts and the like are adopted, and further, the abnormality of the second signal detection unit and the second signal processing unit is detected by the following method. That is, in the conventional multi-rotation encoder, the first signal obtained from the first signal processing unit is used.
Is compared with the second count value (count value of the rotation speed) obtained from the second signal processing unit, and the difference between the two values is determined to be a certain value or more. When it became, it was detected as an abnormality and an alarm was output to the outside.

[0005]

However, in the above-mentioned conventional multi-rotation encoder, the second signal detector or the second signal detector is used.
If the second signal processing unit receives the induced noise and the second signal processing unit miscounts, the first signal processing unit
And a second count value of the second signal processing unit causes a difference, and an alarm is output. Usually, in response to this alarm, a controller such as a machine tool or a robot equipped with the multi-turn encoder stops the entire system. This is because if the rotational position of the rotary shaft over the multiple rotations obtained from the multi-rotation encoder is incorrect, the desired working accuracy cannot be obtained or the device will run out of control.

Therefore, according to the multi-rotation encoder, despite the fact that the first signal detection section and the first signal processing section operate normally and the correct multi-rotation rotational position is output to the outside. , The second signal detection section or the second signal processing section, which is in a standby state in preparation for a backup state, temporarily miscalculated due to inductive noise, so that the entire system was stopped and the system operation was stopped. Was having trouble.

Therefore, some users of the conventional multi-rotation encoder ignore the alarm and continue the operation without stopping the entire system regardless of the presence or absence of the alarm. In this case, if the second signal detection unit and the second signal processing unit temporarily perform a false counting operation due to inductive noise or the like and the second count value (rotational speed) once becomes erroneous, then Even if the counting operation itself returns to normal without receiving induced noise, the second count value is incremented or decremented while remaining erroneous.
Therefore, when the main power supply is once turned off and then turned on again, this erroneous second count value is set as it is to the initial value of the first count value of the first signal processing unit.
Wrong rotational positions of the rotary shaft over multiple rotations are output to the outside, which causes inconvenience such that desired working accuracy cannot be obtained. Further, since the alarm is ignored, the second signal detection section and the second signal processing section are not a temporary malfunction such as inductive noise but have a continuous malfunction such as a component failure. In that case, the abnormality will not be reported as a result, and as with induced noise,
This causes inconvenience such that desired working accuracy cannot be obtained.

The present invention has been made in view of the above circumstances, and provides a multi-rotation encoder capable of reducing the possibility that an incorrect rotational position is output to the outside due to the influence of inductive noise or the like. The purpose is to

The present invention also provides a multi-rotation encoder capable of selectively detecting a continuous malfunction such as a component failure as an abnormality without detecting a temporary malfunction caused by induced noise as an abnormality. The purpose is to provide.

[0010]

In order to solve the above-mentioned problems, a multi-rotation encoder according to the first aspect of the present invention provides an absolute angular position within one rotation of a rotary shaft and a rotational speed of the rotary shaft. A first signal detecting section for detecting a signal, a second signal detecting section for detecting a signal for obtaining the number of rotations of the rotary shaft, and based on the signal from the first signal detecting section, Based on the signal from the first signal processing unit that obtains the absolute angular position and the rotation speed as a first count value by a predetermined counting operation and the signal from the second signal detection unit, a predetermined counting operation is performed. A second signal processing unit that obtains the number of revolutions as a second count value, and when the main power supply is turned on, the first and second signal detection units and the first and second signal detection units by the electric power from the main power supply. The second signal processor is activated to turn on the main power supply. At the same time, the operations of the first signal detection unit and the first signal processing unit are stopped, and the operations of the second signal detection unit and the second signal processing unit continue due to the power from the backup power supply. In the multi-rotation encoder, the second signal processing unit increments or decrements next time when the main power supply shifts from ON to OFF or when a predetermined command is received, or both. Means for setting the first count value as the second count value to be used is provided.

In the multi-rotation encoder according to the second aspect of the present invention, in the first aspect, the second signal processing section has a waveform for shaping the signal from the second signal detection section into a rectangular wave. At least one signal output from the waveform shaping section within a rotation period of a predetermined amount of one rotation or more of the rotation shaft, which includes a shaping section and is determined based on the signal from the first signal detection section. When there is no change, the abnormality detection unit is provided for detecting an abnormality.

A multi-rotation encoder according to a third aspect of the present invention includes a first signal detection unit for detecting a signal for obtaining an absolute angular position of a rotation shaft within one rotation and a rotation speed of the rotation shaft; A second signal detection unit that detects a signal for obtaining the number of rotations of the rotating shaft, and based on the signal from the first signal detection unit, the absolute angular position is obtained and the rotation is performed by a predetermined counting operation. A first signal processing unit that obtains a number as a first count value, and a second counting unit that determines the number of revolutions by a predetermined counting operation based on the signal from the second signal detection unit.
A second signal processing unit for obtaining a count value of the first and second signal processing units, and the first and second signal detection units and the first and second signal processing units by power from the main power source when the main power source is turned on. Is activated, and when the main power supply is turned off, the operations of the first signal detection unit and the first signal processing unit are stopped, and the second signal detection unit and the second signal detection unit are operated by the power from the backup power supply. In the multi-rotation encoder in which the operation of the second signal processing unit is continued, the second signal processing unit is
A predetermined amount of one rotation or more of the rotation shaft, which includes a waveform shaping unit that shapes the signal from the second signal detection unit into a rectangular wave, and is determined based on the signal from the first signal detection unit. During the rotation period of, the abnormality detection unit is provided for detecting an abnormality when at least one signal output from the waveform shaping unit does not change.

A multi-rotation encoder according to a fourth aspect of the present invention is the multi-rotation encoder according to the second or third aspect, further comprising an output section for outputting an alarm when an abnormality is detected by the abnormality detection section. Is.

A multi-rotation encoder according to a fifth aspect of the present invention is the multi-rotation encoder according to any one of the first to fourth aspects, in which when the main power source shifts from off to on, the first signal processing unit And means for setting the second count value as the first count value to be incremented or decremented.

A multi-rotation encoder according to a sixth aspect of the present invention is the multi-rotation encoder according to any one of the first to fifth aspects, wherein the rotational speed and the absolute angular position obtained by the first signal detecting section are: An output unit for outputting in a predetermined signal format is provided.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION A multi-rotation encoder according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a multi-rotation encoder according to an embodiment of the present invention.

The multi-rotation encoder according to this embodiment is
As shown in FIG. 1, the code plate 2 attached to the rotary shaft 1
And a light emitting part 3 for irradiating an optical pattern (not shown) formed on the code plate 2 with light, and light emitted from the light emitting part 3 and transmitted through the optical pattern of the code plate 2 is received and the optical pattern is Optical signal detector for reading (first signal detector)
4, a magnetic signal detection unit (second signal detection unit) 5 for reading a magnetic pattern (not shown) formed by a permanent magnet or the like on the code plate 2, the first and second signal processing circuits 6, 7
And are equipped with.

The optical signal detecting section 4 comprises a plurality of light receiving elements (not shown) such as photodiodes. From these light receiving elements, an absolute value data signal (absolute signal) q within one rotation of the rotary shaft 1 is output. Incremental 2 within 1 rotation
The optical pattern of the code plate 2 and the arrangement of the light receiving elements are set so that the phase signals (A phase and B phase) t and u can be obtained. The magnetic signal detection unit 5 is composed of two magnetic sensors (not shown). From these magnetic sensors, an incremental two-phase signal corresponding to the rotation speed of the rotary shaft 1 (a signal having a phase difference of 90 ° from each other) is output. ) The magnetic pattern of the code plate 2 and the arrangement of the magnetic sensors are set so that A and B can be obtained. The configurations of the code plate 2, the optical signal detection unit 4, and the magnetic signal detection unit 5 as described above are well known as disclosed in, for example, Japanese Patent Laid-Open No. 8-50034. In addition, in the present invention, the incremental 2 within one rotation is used.
A configuration that does not obtain phase signals (A phase and B phase) t, u
May be adopted.

The signal processing circuit 6 obtains the absolute angular position within one rotation of the rotary shaft 1 based on the signals q, t, and u obtained from the optical signal detector 4, and performs a predetermined counting operation to rotate the rotary shaft 1. The number of rotations of 1 is obtained as the first count value. In the present embodiment, as a specific example, the signal processing circuit 6 amplifies the signals q, t, and u from the optical signal detection unit 4, binarizes them, and shapes the waveform into a rectangular wave. And a data conversion circuit 12 for obtaining absolute angular position data within one rotation of the rotary shaft 1 based on the waveform-shaped signals q, t, and u, and rotation of the rotary shaft 1 based on the signal obtained from the data conversion circuit 12. Revolution counter 13 for counting the number
And have. The rotation speed counter 13 receives a signal from the data conversion circuit 12 based on the increase / decrease of the absolute value data in one rotation, and increments or decrements the count value (rotation speed) internally held by this signal.
For example, in the case of an absolute encoder having a resolution of 8 bits per revolution, the revolution counter 13 increments (increases) the count value by 1 when the absolute value within one revolution changes from 255 in decimal to 0, and vice versa. When the absolute value within one rotation changes from 0 to 255 in decimal, the count value is decremented by 1 to obtain the rotation speed of the rotary shaft 1.

The signal processing circuit 7 obtains the number of revolutions of the rotary shaft 1 as a second count value by a predetermined counting operation based on the signals A and B obtained from the magnetic signal detector 5. In the present embodiment, specifically, the signal processing circuit 7 amplifies the signals A and B from the magnetic signal detection unit 5, binarizes them, and shapes the waveform into a rectangular wave.
And a rotation speed counter 15 that counts the rotation speed of the rotating shaft 1 based on the waveform-shaped signals A and B.

As shown in FIG. 1, the first count value (rotation speed) held by the rotation speed counter 13 is input to the rotation speed counter 15. Further, the second count value (rotation speed) held by the rotation speed counter 15 is input to the rotation speed counter 13. When the rotation speed counter 13 receives a first count value set signal from the control circuit 24 described later, the first count value held by the rotation speed counter 13 becomes a second count value ( Number of rotations)
Is set to. That is, the count value held by the rotation speed counter 13 and to be incremented or decremented next time by the rotation speed counter 13 is set to the second count value from the rotation speed counter 15. Further, when the rotation speed counter 15 receives a second count value set signal from the control circuit 24 described later, the second count value held by the rotation speed counter 15 becomes the first count value from the rotation speed counter 13.
Is set to the count value (rotation speed) of. That is, the count value held by the rotation speed counter 15 and to be incremented or decremented next time by the rotation speed counter 15 is set to the first count value from the rotation speed counter 13.

In the multi-rotation encoder according to this embodiment, as shown in FIG. 1, an output circuit 21, a power supply switching supply circuit 22, a control circuit 24, and an abnormality detection circuit 25.
And are equipped with.

The output circuit 21 receives the absolute angular position within one rotation from the data conversion circuit 12 of the signal processing circuit 6 and the rotation speed from the rotation speed counter 13, and outputs them in a predetermined signal format (for example, serial signal). And is output to the outside (for example, the controller of the machine tool on which the multi-rotation encoder is mounted) as a rotation position signal indicating the rotation position of the rotary shaft 1 over multiple revolutions. Further, the output circuit 21 is
An abnormality detection signal from an abnormality detection circuit 25, which will be described later, is directly output as an alarm signal to the outside (for example, the controller).

The power supply switching supply circuit 22 has a voltage detection circuit 23 for detecting a power supply voltage of an external main power supply (for example, 5 V) (for example, the controller), and the voltage detected by the voltage detection circuit 23 is predetermined. When the voltage is equal to or higher than the voltage, the power from the main power source is supplied to all the above-mentioned constituent elements, while when the voltage detected by the voltage detection circuit 23 is equal to or lower than the predetermined voltage, a backup power source such as a lithium battery ( For example, electric power from 3.6 V is supplied only to the magnetic signal detection unit 5 and the signal processing circuit 7. Therefore,
If the main power supply is in the ON state, all the above-mentioned components operate with the power from the main power supply, and if the main power supply is in the OFF state (backup state), the magnetic signal detection unit is supplied with the power from the backup power supply. 5 and the signal processing circuit 7 continue to operate, and the other elements including the optical signal detector 4 and the signal processing circuit 6 stop operating. Such a power supply switching supply circuit 22 is disclosed in, for example, Japanese Patent Laid-Open No. 9-89591.
It is well known as disclosed in Japanese Patent Publication No. The backup power supply is normally arranged outside, but it may be arranged inside the multi-rotation encoder.

Since the magnetic signal detecting section 5 and the signal processing circuit 7 operate even in the backup state, generally, in order to reduce the power consumption in order to extend the backup possible period, the optical signal is generally used. The detection unit 4 and the signal processing circuit 6 are configured to operate with a lower current than that of the detection unit 4 and the signal processing circuit 6. Therefore, even if the same shield measures are taken, the magnetic signal detection unit 5 and the signal processing circuit 7 are more easily affected by the inductive noise than the optical signal detection unit 4 and the signal processing circuit 6.

The control circuit 24 responds to the detection signal from the voltage detection circuit 23 when the voltage of the main power supply is about to exceed a predetermined voltage (that is, when the main power supply is turned on from the backup state). , And supplies the aforementioned first count value set signal to the rotation speed counter 13. Further, the control circuit 24 responds to the detection signal from the voltage detection circuit 23 by
When the voltage of the main power source is about to drop below the predetermined voltage (that is, when the main power source is turned on to the backup state), the second count value set signal described above is supplied to the rotation speed counter 15. Further, in the present embodiment, the control circuit 24, when the main power supply is in the ON state, is external (for example,
In response to a predetermined command from the controller), the aforementioned second count value set signal is supplied to the rotation speed counter 15. As described above, in the present embodiment, the control circuit 24
Supplies the above-described second count value set signal to the rotation speed counter 15 both when the main power-on state shifts to the backup state and when a predetermined command is received from the outside. The second count value set signal may be supplied to the revolution counter 15 only in one case. Only when the control circuit 24 receives a predetermined command from the outside, the second count value set signal is output from the rotation speed counter 15
If the predetermined command is supplied to the control circuit 24 at least immediately before the transition to the backup state,
It is preferable to give

Needless to say, an abnormality detecting section for detecting an abnormality of the optical signal detecting section 4 and the signal processing circuit 6 may be appropriately provided by employing, for example, various known abnormality detecting methods.

Next, the operation state of the multi-rotation encoder according to this embodiment will be described with reference to FIG. Figure 2
[Fig. 6] is an operation state transition table of the multi-rotation encoder according to the present embodiment.

In the main power-on state, the optical signal detecting section 4
Also, the signal processing circuit 6 and the magnetic signal detector 5 and the signal processing circuit 7 operate. As a result, the rotation number counter 13 counts the number of rotations of the rotation shaft 1 based on the signal from the optical signal detection unit 4, and the data conversion circuit 12 outputs the absolute angular position within one rotation, and the rotation by these is performed. The position signal is output from the output circuit 21 to the outside. Further, based on the signal from the magnetic signal detection unit 5, the rotation speed counter 15 of the signal processing circuit 7 counts the rotation speed of the rotary shaft 1. The count value by the rotation speed counter 15 is not output to the outside of the multi-rotation encoder. The first column in FIG. 2 shows a state in which the rotation speed counters 13 and 15 are performing a normal counting operation in the main power-on state.

As shown in the second column in FIG. 2, when the critical induction noise is applied to the magnetic type signal detection section 5 or the signal processing circuit 7 in the main power-on state, the rotation speed counter 1
A false count of 5 occurs. However, since the rotation speed counted by the rotation speed counter 13 is used for the encoder output, the rotation position signal output from the multi-rotation encoder remains correct and no inconvenience occurs. Since the induced noise is temporary, the counting operation of the rotation speed counter 15 returns to normal after that, but since the incorrect count value is incremented or decremented, the count value eventually becomes incorrect. Will remain.

Next, as in the third column in FIG. 2, when shifting to the backup state, the control circuit 24 responding to the detection signal from the voltage detection circuit 23 causes the rotation speed counter 15 to move to the second position. The count value held in the rotation speed counter 15 is set to the count value of the rotation speed counter 13 (correct rotation speed).
Therefore, the incorrect count value due to the induced noise is reset to the correct count value (correct rotation speed).

Therefore, in the backup state, as shown in FIG.
As in the fourth column in the middle, the count value counted by the rotation speed counter 15 is the correct rotation speed. In the backup state, the optical signal detection unit 4 and the signal processing circuit 6
Has stopped working.

When the main power is turned on again and the main power is turned on, the control circuit 24 responding to the detection signal from the voltage detection circuit 23 responds to the detection signal from the voltage detection circuit 23 as shown in the fifth column in FIG. A first count value set signal is supplied to 13, and the count value held in the rotation speed counter 13 is set to the count value in the rotation speed counter 15. Therefore, even if the rotating shaft 1 is rotating in the main power-off state, the count value of the rotation number counter 13 becomes the correct rotation number as shown in the sixth column in FIG. Is properly restored.

Referring again to FIG. 1, the abnormality detection circuit 25
Is a rectangular wave incremental signal output from the waveform shaping circuit 14 of the signal processing circuit 7 within a predetermined rotation period of one rotation or more of the rotary shaft 1 determined based on the signal from the optical signal detection unit 4. When there is no change in at least one of the two-phase signals A and B, an abnormality detection signal is output and given to the output circuit 21. As described above, the output circuit 21 outputs the abnormality detection signal as it is to the outside as an alarm signal.

FIG. 3 is a circuit diagram showing an example of the abnormality detection circuit 25. FIG. 4 is a time chart showing the operation of the abnormality detection circuit 25 shown in FIG.

In the example shown in FIG. 3, the abnormality detection circuit 25 is
A signal change recognition circuit 31A that recognizes a signal change of the signal A output from the waveform shaping circuit 14 of the signal processing circuit 7, and a signal change recognition circuit 31B that recognizes a signal change of the signal B output from the waveform shaping circuit 14. , Signal change recognition circuit 31
Based on the outputs from the change data holding circuit 32A that holds the change data recognized by A, the change data holding circuit 32B that holds the change data recognized by the signal change recognition circuit 31B, and the outputs from the change data holding circuits 32A and 32B. And a reset signal for resetting the held data of the change data holding circuits 32A and 32B based on the signal from the data conversion circuit 12 of the signal processing circuit 6, and A signal generation circuit 34 that generates a determination timing signal that determines the determination timing in the determination circuit 33.

The signal generation circuit 34 includes the data conversion circuit 12
Based on the signal from the rotation axis 1 when the rotation shaft 1 rotates in either direction (immediately before the count value (rotation speed) of the rotation speed counter 13 is incremented or decremented). One pulse of H (high) is generated as the determination timing signal. It goes without saying that such a determination timing signal can be generated based on the absolute value within one rotation and its change.

Further, the signal generating circuit 34, when the rotary shaft 1 rotates in either direction, immediately after the predetermined reference rotation position of the one rotation (here, the count value (rotation speed) of the rotation speed counter 13). Is immediately after the position where is incremented or decremented) is generated as the reset signal. It goes without saying that such a reset signal can also be generated based on the absolute value within one rotation and its change.

As can be seen from the above description, FIG.
As shown in, in the rotating situation of the rotating shaft 1 in which the count value of the rotating speed counter 13 is sequentially incremented,
The determination timing signal is output from the signal generation circuit 34 immediately before the count value of the rotation speed counter 13 is incremented. Further, in this situation, the reset signal is output from the signal generation circuit 34 immediately after the count value of the rotation speed counter 13 is incremented.

The signal change recognition circuit 31A includes D flip-flops 41a and 42a and an exclusive OR (exclusive OR) gate 43a. Clock signals from a clock generation circuit (not shown) are input to the T input portions of the D flip-flops 41a and 42b, respectively. The signal A output from the waveform shaping circuit 14 of the signal processing circuit 7 is input to the D input section of the D flip-flop.
Has been entered. The Q output section of the D flip-flop 41a and the D input section of the D flip-flop 42a are connected, and these are connected to one input section of the gate 43a. The Q output section of the D flip-flop 42a is connected to the other input section of the gate 43a. Therefore,
According to the signal change recognition circuit 31A, when the signal A changes from H to L and when it changes from L to H, the gate 43a.
To H pulse signals are obtained.

The signal change recognition circuit 31B is similar to the signal change recognition circuit 31A in that the elements 41a, 42a, 43a.
D flip-flops 41b and 42 respectively corresponding to
b and an exclusive OR gate 43b.

The change data holding circuit 32A includes an OR gate 44a and a D flip-flop 45a with a reset function.
It consists of and. One input of the OR gate 44a is connected to the output of the gate 43a,
The other input of a is connected to the Q output of the D flip-flop 45a. The output of the OR gate 44a is D
It is connected to the D input section of the flip-flop 45a.
The clock signal is input to the T input section of the D flip-flop 45a. The reset signal from the signal generation circuit 34 is input to the reset input section of the D flip-flop 45a. Therefore, according to the change data holding circuit circuit 32A, once the H signal is output from the gate 43a of the signal change recognition circuit 31A, the D flip-flop 45a of the D flip-flop 45a continues from that time until the reset signal is given from the signal generation circuit 34. An H signal is obtained from the Q output section.

Similar to the change data holding circuit 32A, the change data holding circuit 32B is composed of an OR gate 44b corresponding to the elements 44a and 45a and a D flip-flop 45b with a reset function.

The decision circuit 33 is composed of a NAND gate 46, an OR gate 47 and a D flip-flop 48. One input portion of the NAND gate 46 is connected to the Q output portion of the D flip-flop 45a of the change data holding circuit 32A. The other input part of the NAND gate 46 is connected to the Q output part of the D flip-flop 45b of the change data holding circuit 32B. Nand Gate 46
The output part of is connected to one input part of the OR gate 47. The other input of the OR gate 47 is connected to the Q output of the D flip-flop 48. The output of the OR gate 47 is connected to the D input of the D flip-flop 48. The determination timing signal is input from the signal generation circuit 34 to the T input section of the D flip-flop 48. The Q output section of the D flip-flop 48 is
When an abnormality is detected, the abnormality detection circuit 25 outputs an abnormality detection signal as an H signal.
It is connected to the output circuit 21 inside. Therefore, according to the determination circuit 33, either the Q output of the D flip-flop 45a or the Q output of the D flip-flop 45b is L.
In other words, (that is, when there is no signal change in either the A signal or the B signal during the one rotation), the H signal is output from the Q output section of the D flip-flop 48 as the abnormality detection signal, and otherwise. If, then the D flip-flop 48
The L signal indicating that there is no abnormality is output from the Q output section of the.

According to this abnormality detecting circuit 25, as shown in FIG.
In the situation where the count value of the rotation speed counter 13 is sequentially incremented as shown in FIG.
As shown in FIG. 4C, the signal B from the waveform shaping circuit 14 is always normal, but as shown in FIG. 4B, the signal A from the waveform shaping circuit 14 is normal until time t1 and is a signal at time t1. When sticking (fixing to the H signal in this example) occurs, an abnormality detection signal is output after time t2, as shown in FIG.

The signal sticking (fixed to the H or L signal) as described above is caused by, for example, a resistor that determines the threshold level of the binarizing circuit constituting the waveform shaping circuit 14 failing to cause the resistance. It occurs when the value becomes an unexpected value. Unlike the case of induced noise or the like, such signal sticking occurs continuously rather than temporarily.

Here, a multi-rotation encoder of a comparative example to be compared with the multi-rotation encoder according to the present embodiment will be described.
This will be described with reference to FIGS. 5 and 6. FIG. 5 is a block diagram showing a schematic configuration of a multi-rotation encoder of a comparative example. In FIG. 5, elements that are the same as or correspond to the elements in FIG. 1 are assigned the same reference numerals, and duplicate descriptions thereof will be omitted. Figure 6
3 is an operation state transition table of the multi-rotation encoder shown in FIG. 5, which corresponds to FIG.

The multi-rotation encoder shown in FIG. 5 differs from the multi-rotation encoder shown in FIG. 1 only in the points described below.

First, in the multi-rotation encoder of the comparative example shown in FIG. 5, the first count value (rotation speed) held by the rotation speed counter 13 is not input to the rotation speed counter 15, Further, the count value set signal is not input from the control circuit 24 to the rotation speed counter 15. Further, the control circuit 24 responds to the detection signal from the voltage detection circuit 23 by
When transitioning from the main power-on state to the backup state,
A reset signal for setting the count value held by the rotation speed counter 15 to zero is supplied to the rotation speed counter 13.

Secondly, in the multi-rotation encoder of the comparative example shown in FIG. 5, the abnormality detection circuit 25 in FIG. 1 is removed and an abnormality detection circuit 50 is provided instead. The abnormality detection circuit 50 uses the rotation speed counter 13 of the signal processing circuit 6.
Comparing the first count value (rotation speed) of No. 2 with the second count value (rotation speed) of the rotation speed counter 15 of the signal processing circuit 7,
When the difference between the two values exceeds a certain value, an abnormality detection signal is output and given to the output circuit 21. Output circuit 21
Outputs the abnormality detection signal as it is to the outside as an alarm signal.

Also in the multi-rotation encoder of the comparative example shown in FIG. 5, as in the first and second columns in FIG. 6, the operation in the first main power-on state is the operation of the present embodiment shown in FIG. This is the same as the operation of the multi-rotation encoder according to the embodiment (first row and second row in FIG. 2).

However, in the multi-rotation encoder of the comparative example shown in FIG. 5, after the rotation counter 15 is once erroneously counted due to induced noise in the main power-on state as in the second column in FIG. Since the rotation speed counter 13 is only reset at the time of transition to, the count value of the rotation speed counter 15 remains the original count value. Therefore, as shown in the third to sixth columns in FIG. Even if the counting operation of the rotation speed counter 15 returns to the normal state due to no influence of, the count value is incremented or decremented with respect to the erroneous count value, and the count value remains erroneous. Then, when the main power supply is turned on again and the main power supply is turned on, as shown in the fifth column in FIG.
Since the rotational speed counter 13 is incremented or decremented with respect to this erroneous count value, the count value of the rotational speed counter 13 becomes an erroneous rotation speed, and this is output to the outside via the output circuit 21. It will be output.

On the other hand, in the multi-rotation encoder according to the present embodiment shown in FIG. 1, as shown in the third column in FIG.
When shifting to the backup state, the count value held in the rotation speed counter 15 is set to the count value of the rotation speed counter 13 (correct rotation speed), and the count value erroneous due to induction noise is corrected. Numerical value (correct rotation speed)
Is set again, and thereafter, the rotation speed counter 15 counts a correct count value. Therefore, when the main power is turned on again and the main power is turned on, the fifth power supply in FIG.
Like the column, the correct count value is restored in the rotation speed counter 13, and the count value counted by the rotation speed counter 13 after that also shows the correct rotation speed, which is output to the outside via the output circuit 21. Is output.

As described above, according to the present embodiment, it is possible to reduce the possibility that an incorrect rotational position is output to the outside due to the influence of inductive noise or the like, as compared with the comparative example described above.

Further, in the multi-rotation encoder of the comparative example shown in FIG. 5, since the above-mentioned abnormality detecting circuit 50 is adopted, the signal A or the signal A due to the failure of parts in the magnetic type signal detecting section 5 or the waveform shaping circuit 14 is used. The abnormality detection signal is output not only in the case of a continuous abnormality in which the signal B sticks to the signal, but also in the case where the magnetic type signal detection unit 5 and the signal processing circuit 7 have malfunctions due to induced noise. And eventually an alarm signal is output to the outside. Therefore, when the user of the multi-rotation encoder stops the entire system by the alarm signal, the optical signal detection unit 4 and the signal processing circuit 6 operate normally to output the correct multi-rotation rotation position to the outside. However, the rotation speed counter 13 is temporarily caused by induced noise.
However, the whole system is stopped just because the number is wrongly counted, and the operation of the system is hindered. On the other hand, if the user of the multi-rotation encoder ignores the alarm signal, the signal A or the signal B in the magnetic signal detection unit 5 or the waveform shaping circuit 14 may be stuck due to a component failure or the like, causing a continuous abnormality. Will not be reported as a result.

On the other hand, in the present embodiment, the abnormality detecting circuit 25 does not detect an abnormality when the magnetic signal detecting section 5 or the signal processing circuit 7 has induced noise and malfunctions. This is because, for example, even if induced noise is applied to the waveform shaping circuit 14, the signal changes only increase in the A signal and the B signal from the waveform shaping circuit 14 during one rotation of the rotating shaft, and the signal change is increased. Because there is no change in what happens. On the other hand, since the abnormality detection circuit 25 detects the signal clinging of the A signal and the B signal from the waveform shaping circuit 14 as an abnormality, the magnetic signal detection unit 5 and the waveform shaping circuit 14 are detected.
A continuous abnormality due to a failure of a component forming the above will be detected.

As described above, in this embodiment, the abnormality detection circuit 25 does not detect a temporary malfunction of the magnetic signal detection section 5 and the signal processing circuit 7 due to inductive noise or the like as an abnormality, and detects the magnetic signal. It is possible to selectively detect an abnormal operation such as a continuous operation failure such as a failure of a component forming the detection unit 5 or the waveform shaping circuit 14. Therefore,
According to the present embodiment, there is no possibility that the system will be stopped unnecessarily, and it is possible to appropriately notify the above-mentioned continuous abnormality.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to these embodiments.

For example, in the above-described embodiment shown in FIG. 1, an optical signal detecting section may be used instead of the magnetic signal detecting section 5. In this case, the light emitting section 3 can be shared as a light source for the optical signal detecting section 4 and a light source for the optical signal detecting section in place of the magnetic signal detecting section 5.

Further, for example, in the present invention, the above-mentioned FIG.
In the embodiment shown in, the abnormality detection circuit 25 may be removed. Further, in the present invention, in the above-described comparative example shown in FIG. 5, the abnormality detection circuit 50 may be removed and the abnormality detection circuit 25 in FIG. 1 may be provided instead.

[0062]

As described above, according to the present invention,
It is possible to provide a multi-rotation encoder that can reduce the possibility that an incorrect rotational position is output to the outside due to the influence of induced noise or the like.

Further, according to the present invention, multi-rotation can selectively detect a continuous malfunction such as a component failure without detecting a temporary malfunction due to induction noise or the like as a malfunction. An encoder can be provided.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a multi-rotation encoder according to an embodiment of the present invention.

2 is an operation state transition table of the multi-rotation encoder shown in FIG.

3 is a circuit diagram showing an example of an abnormality detection circuit used in the multi-rotation encoder shown in FIG.

FIG. 4 is a time chart showing the operation of the abnormality detection circuit shown in FIG.

FIG. 5 is a block diagram showing a schematic configuration of a multi-rotation encoder of a comparative example.

6 is an operation state transition table of the multi-rotation encoder shown in FIG.

[Explanation of symbols]

1 rotation axis 2 code plate 3 light emitting part 4 Optical signal detector (first signal detector) 5 Magnetic signal detector (second signal detector) 6,7 Signal processing circuit 11,14 Wave shaping circuit 12 Data conversion circuit 13,15 revolution counter 21 Output circuit 22 Power supply switching circuit 23 Voltage detection circuit 24 Control circuit 25 Abnormality detection circuit

Claims (6)

[Claims] 1. A first signal detection unit for detecting a signal for obtaining an absolute angular position within one rotation of a rotation shaft and a rotation speed of the rotation shaft, and a signal for obtaining a rotation speed of the rotation shaft. A second signal detecting section for detecting, and a first count value for obtaining the absolute angular position and the rotation speed as a first count value by a predetermined counting operation, based on the signal from the first signal detecting section. And a second signal processing unit that obtains the rotation speed as a second count value by a predetermined counting operation based on the signal from the second signal detection unit. When the main power supply is turned on, the first and second signal detection units and the first and second signal processing units are operated by the electric power from the main power supply, and when the main power supply is turned off, the first signal detection unit And the operation of the first signal processing unit is stopped, In a multi-rotation encoder in which the operations of the second signal detection unit and the second signal processing unit are continued by the power from a backup power supply, when the main power supply shifts from ON to OFF and when a predetermined command is received. In either or both of the cases, the first signal is used as the second count value to be incremented or decremented next time by the second signal processing unit.
A multi-rotation encoder, characterized in that it is provided with means for setting the count value of. 2. The second signal processing unit includes a waveform shaping unit that shapes the signal from the second signal detection unit into a rectangular wave, and based on the signal from the first signal detection unit. An abnormality detection unit that performs abnormality detection when at least one signal output from the waveform shaping unit does not change within a predetermined amount of rotation period of one rotation or more of the rotation shaft determined by The multi-rotation encoder according to claim 1, wherein: 3. A first signal detection unit for detecting a signal for obtaining an absolute angular position within one rotation of the rotating shaft and a rotating speed of the rotating shaft, and a signal for obtaining a rotating speed of the rotating shaft. A second signal detecting section for detecting, and a first count value for obtaining the absolute angular position and the rotation speed as a first count value by a predetermined counting operation, based on the signal from the first signal detecting section. And a second signal processing unit that obtains the rotation speed as a second count value by a predetermined counting operation based on the signal from the second signal detection unit. When the main power supply is turned on, the first and second signal detection units and the first and second signal processing units are operated by the electric power from the main power supply, and when the main power supply is turned off, the first signal detection unit And the operation of the first signal processing unit is stopped, In the multi-rotation encoder in which the operations of the second signal detection unit and the second signal processing unit are continued by the power from the backup power source, the second signal processing unit is configured to operate from the second signal detection unit. The waveform shaping section includes a waveform shaping section that shapes the signal into a rectangular wave, and the waveform shaping is performed within a predetermined rotation period of one rotation or more of the rotation shaft that is determined based on the signal from the first signal detection section. A multi-rotation encoder comprising an abnormality detection unit that detects an abnormality when at least one signal output from the unit does not change. 4. The multi-rotation encoder according to claim 2, further comprising an output unit that outputs an alarm to the outside when an abnormality is detected by the abnormality detection unit. 5. The first count value to be incremented or decremented next time by the first signal processing unit when the main power supply shifts from OFF to ON,
The multi-rotation encoder according to any one of claims 1 to 4, further comprising means for setting the second count value. 6. An output unit for outputting the rotation speed and the absolute angular position obtained by the first signal detection unit in a predetermined signal format.
The multi-rotation encoder according to any one of 1.