JP3001149B2 - Encoder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder for outputting an M + 1 digit gray binary number.

[0002]

2. Description of the Related Art In order to know a rotation angle and a movement position, gray 2
Encoders that output hexadecimal numbers are often used. A conventional M + 1 digit gray binary encoder outputs M
It has a +1 digit encoding plate and a sensor which detects and outputs "1" or "0" of each digit of the encoding plate.

[0003]

As described above, the conventional encoder for outputting the M + 1-digit gray binary number is M
It has a +1 digit encoding plate and an output sensor that detects "1" or "0" of each digit of the encoding plate.

That is, to output an M + 1 digit Gray binary number, an M + 1 digit encoding plate was required. For this reason, the shape of the encoding plate becomes large and the shape of the encoder becomes large. SUMMARY OF THE INVENTION It is an object of the present invention to provide an encoder that is improved so that the shape of an encoding plate is reduced.

[0005]

Means adopted by the present invention to solve the above-mentioned problems will be described. An encoder for outputting an M + 1 digit Gray binary number, comprising an M digit code recording unit encoded according to the Gray encoding rule, a first sensor for detecting recording information of each digit of the code recording unit,
It is installed at a distance of 離 れ of the information recording length of the M-th digit of the code recording means from the detection position of the M-th digit of the first sensor.
A second sensor for detecting single digit information.

[0006]

In the code recording means, M digit 1 or 0 information excluding the highest digit of the (M + 1) digit coded according to the Gray coding rule is recorded. The first sensor detects the recorded information of each digit of the code recording means and outputs a signal of M digits.

The second sensor is installed at a position which is の of the M-digit information recording length of the code recording means from the detection position of the M-th digit of the first sensor. The recording information is detected and a signal of the (M + 1) th digit is output. As described above, M-digit information excluding the highest digit encoded according to the Gray encoding rule is recorded, and the (M + 1) -th encoder output is the M-th information recording length from the M-th information detection position. Of 1
Since the sensor is installed at a position separated by a distance of / 2 and the output is performed, the recording of the encoded information can be reduced by one digit and the size can be reduced.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a block diagram of the embodiment, and FIG. 2 is a specific example in which the rotation angle is encoded and output in the embodiment. First, a specific example in the case where the rotation angle is encoded and output will be described with reference to FIG.

A slit disk 1 is fixed to the shaft shown in FIG. 2A, and when the shaft rotates, the slit disk 1 is fixed.
Also rotate. As shown in FIG. 2B, the slit disk 1 is provided with four tracks on a concentric circle, and each track is provided with a slit according to the Gray coding rule. Although four tracks are used in the embodiment, the number of tracks is not limited to four.

As shown in FIG. 2A, a first sensor 2 composed of a light-emitting element and a light-receiving element corresponds to each track of the slit disk 1, and the track corresponding to the highest digit is used. The second sensor 3 is installed at a position １ ／ of the slit length of the highest digit (to be described in detail later).

Therefore, when the pointer of the meter is fixed to the shaft, the encoded output corresponding to the indicated angular position of the pointer can be obtained from the first and second sensor outputs. The slit disk 1 in FIG. 1 shows a case where the slit disk 1 shown in FIG. 2B is developed on a straight line corresponding to an angle. The thick black line indicates the slit portion.

The slit is provided according to the Gray coding rule. That is, the case of FIG. 1 shows a case where the angle is output every 5 degrees. First, as shown in FIG. 3, numbers 0 to 31 are sequentially assigned to ranges every 5 degrees.

The next number is represented by a natural binary number. Next, a natural binary number is converted to a gray binary number. The conversion from the natural binary to the gray binary is obtained by using the output of the exclusive OR circuit 14 of the own digit and the upper digit as the output of the own digit as shown in FIG.

As shown in FIG. 1, when encoding at every angle of 5 degrees is output, the number 31, ie, the angle 155
Five digits may be used up to degrees, but six digits are required to encode and output an angle of 155 degrees or more. That is, the number of bits required to represent the highest value of the number in a natural binary number is the number of digits.

Next, each bit represented by the gray binary number is made to correspond to the track of the slit disk, and a slit is provided in a range portion where the numerical value is 1. However, a slit corresponding to the highest digit (fifth digit in FIG. 1) is not provided. The encoded output of the highest digit is output as follows.

As can be understood from FIGS. 1 and 3, the starting position of the slit corresponding to the fifth digit starts from the middle point of the fourth slit and is opened to the final angular position. Therefore, the starting point D of the fourth digit slit
Where d is the distance between the slit and the starting point E of the slit corresponding to the fifth digit, d is represented by d = (the slit length of the fourth digit) / 2 (1), Is detected at a distance d, a fifth digit encoded output can be obtained.

In FIG. 1, the first sensor 2 outputs "1" when the slit disk 1 rotates and the slit is positioned on the sensor, and outputs "0" when the slit is not positioned. Further, the second sensor 3 is provided at a distance d from the sensor position corresponding to the fourth digit, and is “1” when the slit of the fourth digit is located on the second sensor 3 and is not located. In this case, "0" is output and the highest digit of the encoder is output.

In this embodiment, the gray code information for encoding and output is recorded on a slit disk, but a reflecting plate for reflecting light corresponding to the slit, or magnetically recording "1" or "0" is recorded. You may make it comprise with a magnetic plate etc. Further, in the embodiment, the encoded output corresponding to the rotation angle is output, but a slit may be provided on a straight line as shown in FIG. 1 to encode and output the moving amount (position).

[0019]

As described above, according to the present invention, the following effects can be obtained. The M-digit information excluding the highest digit encoded according to the Gray encoding rule is recorded, and the encoder output of the (M + 1) th digit is １ ／ of the information recording length of the (M) -th digit from the detection position of the (M) -th digit. Since the sensor is installed at the position where the coded information is output, the recording of the coded information can be reduced by one digit and the size can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an embodiment of the present invention.

FIG. 2 is a specific example of a case where a rotation angle is encoded and output in the embodiment.

FIG. 3 is a diagram illustrating encoding according to the Gray encoding rule of the embodiment.

FIG. 4 is a diagram illustrating conversion from a natural binary number to a gray binary number.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Slit disk 2 1st sensor 3 2nd sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01D 5/249 G01D 5/34 H03M 7/16

Claims (1)

(57) [Claims] 1. An encoder for outputting an M + 1-digit Gray binary number, comprising: an M-digit code recording unit encoded according to a Gray encoding rule; and an encoder for detecting recording information of each digit of the code recording unit. One sensor and a half of the Mth digit information recording length of the code recording means from the Mth digit detection position of the first sensor.
An encoder comprising: a second sensor for detecting one-digit information.