JP2001124591A - Absolute encoder - Google Patents

Abstract

(57) [Problem] To provide an absolute encoder that can be used in a wide range from low-speed rotation to high-speed rotation while achieving high speed and high resolution. SOLUTION: When the rotation speed detected by the rotation speed detection means 24 is low, position information detected from all slits is output, and when the rotation speed is high, a signal detected from a slit with high resolution is invalidated. Output.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute encoder used for positioning various industrial equipment and automatic equipment.

[0002]

2. Description of the Related Art Conventionally, an absolute value encoder used for positioning various industrial equipment and automatic equipment has a large number of slits having different resolutions as shown in FIG. In this case, a plurality of signals are obtained, an absolute position within one rotation is detected, and position information is output.

[0003]

However, in the above-described conventional configuration, as the rotational speed of the absolute value encoder increases, the detection frequency of a signal obtained from a slit having a high resolution also increases accordingly, and the signal processing capability and the like are limited. Therefore, the reliability of the position detection signal is reduced, and the upper limit of the rotation speed must be set to, for example, 3000 rotations per minute.
If the resolution of the absolute value encoder is increased, the rotation speed cannot be increased, and when positioning the device using the position signal output of the absolute value encoder, there is a problem that high-speed and high-resolution positioning cannot be performed.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an absolute encoder that can be used in a wide range from low-speed rotation to high-speed rotation while achieving high speed and high resolution.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a rotating speed detecting means for detecting a rotating speed of an absolute value encoder, and invalidating a signal according to the rotating speed of the rotating speed detecting means. When the rotation speed of the absolute value encoder is low, the position information of all slits is valid, and when the rotation speed of the absolute value encoder is high, only a plurality of high-resolution signals are used. This is an absolute encoder that outputs invalid position information.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to solve the above-mentioned problems, the present invention provides a method for detecting a plurality of position signals optically or magnetically from a number of slits having different resolutions in which position information is carved.
In an absolute value encoder for detecting an absolute position in the rotation, a rotational speed detecting means for detecting a rotational speed of the absolute value encoder, and a signal switching means for invalidating a signal according to the rotational speed of the rotational speed detecting means. When the rotation speed of the absolute encoder is low, the position information of all slits is valid, and when the rotation speed of the absolute encoder is high, the position information is output in which only a plurality of high resolution signals are invalidated. Absolute value encoder.

The absolute value encoder according to claim 1, wherein the position information of the absolute value encoder is output by serial communication.

Further, a plurality of position signals are optically or magnetically detected from a number of slits having different resolutions engraved with position information, and signals from one or a plurality of slits having the highest resolution are detected by using one or more signals. A doubling processing means for obtaining a signal with a higher resolution, a rotation speed detecting means for detecting a rotation speed of an absolute value encoder, and an output signal of the doubling processing means invalidated according to an output of the rotation speed detection means. Signal switching means, when the rotation speed of the absolute value encoder is low, the position information of all slits is valid, and when the rotation speed of the absolute value encoder is high, the output signal from the double processing means is output. This is an absolute encoder that outputs invalid position information.

The absolute value encoder according to claim 3, wherein the position information of the absolute value encoder is output by serial communication.

As described above, when the rotation speed of the absolute value encoder is increased, a plurality of signals on the higher resolution side or output signals of the multiplying means are invalidated by the signal switching means, so that the absolute value encoder can be used. Even at a high rotation speed, the reliability of the position detection information can be ensured, and a high resolution can be ensured at the time of stopping or at a low rotation speed.

Further, by serially communicating the position information, the absolute value encoder can be saved.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In FIG. 1, an absolute value encoder includes a glass disk 20 on which a number of slits 11 are cut from a slit having the highest resolution to a slit having the lowest resolution, and a slit 11 formed on the glass disk 20. Light emitting element 21 and light receiving element 22 for optically detecting a position signal from
And signal processing means 23 for further shaping the waveform of the position signal
Having. Further, it has a rotation speed detecting means 24 based on the position signal detected from the slit 11 on the lower resolution side, and the signal processing means 2 according to the output of the rotation speed detecting means 24.
3 has a signal switching means 27 for invalidating the output.

When the rotation speed of the absolute value encoder is lower than the set rotation speed, the signal switching means 27 outputs the position signals detected from all the slits 11 as valid. When the rotation speed of the absolute value encoder is higher than the set rotation speed, the signal switching unit 27 outputs the position information of the slit 11 having high resolution as invalid.

When driven at a high speed, the resolution is lower than that at a low speed. However, the necessary resolution in controlling the device in response to the output signal of the absolute encoder is sufficiently ensured. . The communication means 25
Outputs the position signal output from the signal processing unit 23 and the speed signal output from the rotational speed detecting unit 24 through serial communication, so that the absolute value encoder can be saved in line.

(Embodiment 2) In FIG. 2, a multiplying processing means 26 outputs a signal obtained by multiplying a plurality of position signals outputted from the light receiving element into position signals of higher resolution. A signal switching unit that has a rotation speed detection unit based on the position signal detected from the slit on the low resolution side, and disables the output of the doubling unit according to the output of the rotation speed detection unit; 27.

When the rotation speed of the absolute value encoder is lower than the set rotation speed, the signal switching means 27 outputs the position signal of the multiplication processing means 26 as valid. When the rotation speed of the absolute value encoder is higher than the set rotation speed, the signal switching means 27
Is output as invalid.

Since the communication means 25 outputs the position signal output from the signal processing means 23 and the speed signal output from the rotational speed detecting means 24 by serial communication, the absolute value encoder can be omitted as in the first embodiment. Linearization is possible.

[0019]

As is apparent from the above embodiment, according to the first or third aspect of the present invention, when the rotation speed of the absolute value encoder is increased, a plurality of signals on the higher resolution side or multiplication processing are performed. By disabling the output signal of the means by the signal switching means, the reliability of the position detection information can be ensured even when the absolute value encoder becomes a high rotation speed, and a high resolution is obtained when the rotation is stopped or at a low rotation speed. Can be secured.

Therefore, if the device is positioned using the position signal output of the absolute value encoder, the positioning can be performed at high speed and with high resolution.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an absolute encoder showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram of an absolute encoder showing a second embodiment of the present invention;

FIG. 3 is a configuration diagram of a conventional absolute value encoder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Slit 20 Glass disk 21 Light emitting element 22 Light receiving element 23 Signal processing means 24 Rotation speed detecting means 25 Communication means 26 Multiplication processing means 27 Signal switching means

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Claims (4)

[Claims] 1. An absolute value encoder for optically or magnetically detecting a plurality of position signals from a number of slits having different resolutions engraved with position information and detecting an absolute position within one rotation. Rotation speed detection means for detecting a speed, and signal switching means for invalidating a signal according to the rotation speed of the rotation speed detection means, and when the rotation speed of the absolute encoder is low, the position information of all slits is provided. An absolute encoder that outputs position information that is enabled and that only a plurality of high-resolution signals are disabled when the rotation speed of the absolute encoder increases. 2. The absolute encoder according to claim 1, wherein the position information of the absolute encoder is output by serial communication. 3. A plurality of position signals are optically or magnetically detected from a number of slits having different resolutions engraved with position information, and signals from one or a plurality of slits having the highest resolution are detected using one or more signals. A doubling processing means for obtaining a signal with a higher resolution, a rotation speed detecting means for detecting a rotation speed of an absolute value encoder, and an output signal of the doubling processing means invalidated according to an output of the rotation speed detection means. Signal switching means, when the rotation speed of the absolute value encoder is low, the position information of all slits is valid, and when the rotation speed of the absolute value encoder is high, the output signal from the double processing means is output. Absolute encoder that outputs invalid position information. 4. The absolute value encoder according to claim 3, wherein the position information of the absolute value encoder is output by serial communication.