JP5041722B2 - Absolute encoder - Google Patents

Description

  The present invention relates to an absolute encoder having a plurality of resolutions.

Conventionally, as a technology that "allows absolute type rotary encoders to be installed without positioning at the origin", after mounting and connecting an absolute type rotary encoder to a servo motor, etc., an origin reset signal is sent at the origin position. To do. Then, the origin reset signal detection circuit 14 detects this signal, and the memory 10 holds binary data for the rotation angle at that time. Thereafter, by subtracting the value held in the memory from the outputs of the gray / binary conversion circuit 7 and the multi-rotation counter 9, the rotation angle from the set origin position can be detected. "Has been proposed.
JP-A-6-129875 (summary)

However, in the conventional absolute encoder, it is possible to set an arbitrary position as the detection origin without positioning the origin, but the resolution that can be realized by one absolute encoder is limited to a certain type. It was.
An object of the present invention is to realize a plurality of types of resolution with one absolute encoder.

Absolute encoder according to the present invention, the absolute position corresponding to the rotation angle of the rotating body is detected based on the first detection resolution predetermined, the absolute position output means for outputting a signal representing the absolute position, the Storage means for storing a correspondence table between the output value at the first detection resolution and the corresponding value at the second detection resolution, and storing the corresponding value of the first detection resolution at the second detection resolution. Computing means for outputting the corresponding value with reference to the correspondence table stored in the means, and the storage means stores information indicating the value of the resolution to be used as the second detection resolution. When the information is received and the resolution value that is the information is different from the first detection resolution value, the means compensates the corresponding value at the second detection resolution according to the resolution value. It is characterized in that.

Further, the calculation means receives a signal to set a detection origin of the absolute position of the rotating body,
The position corresponding to the output signal of the absolute position output means when the signal is received is set as a new detection origin.

Further, when the calculation means receives a signal to set the detection origin of the absolute position of the rotating body,
A value corresponding to the output signal of the absolute position output means at the time of receiving the signal is used as a new detection origin, and the value of the correspondence table is rewritten.

Further, the calculation means receives a signal for setting information indicating the resolution value and stores the signal in the storage means,
When a signal indicating that the information should be output is received, the information is read from the storage means and output.

The absolute position output means includes
It is characterized by using a slit plate on which a bit pattern representing an absolute position corresponding to the rotation angle of the rotating body is formed.

The absolute position output means includes
The magnet is configured to rotate in accordance with a rotating operation of a rotating body, a magnetic sensor that detects magnetism of the magnet, and a detection circuit that converts a detection value of the magnetic sensor into an electric signal. Is.

According to the absolute encoder according to the present invention,
With one absolute encoder, a plurality of types of resolution outputs can be obtained, and an arbitrary position can be set as a detection origin without positioning the origin.

Embodiment 1 FIG.
FIG. 1 is a functional block diagram of an absolute encoder according to Embodiment 1 of the present invention.
The absolute encoder shown in FIG. 1 includes an LED 101, a fixed slit plate 102, a rotary slit plate 103, a photodiode 104, an amplifier circuit 105, a shaping circuit 106, an arithmetic unit 107, and an interface 108.
The LED 101 is a light source, and light emitted from the LED 101 strikes a photodiode 104 as a light receiving element through a fixed slit plate 102 and a rotary slit plate 103 and is converted into an analog electric signal.
On the fixed slit plate 102, a light shielding portion and a light transmitting portion are formed by a method such as vapor deposition or etching.
A bit pattern representing a gray code is formed on the rotary slit plate 103 by a method such as vapor deposition or etching.
The light that has passed through the fixed slit plate 102 and the rotary slit plate 103 and received by the photodiode 104 becomes an analog electric signal that represents the absolute position according to the rotation angle of the rotary slit plate 103 as a gray code, and is supplied to the amplifier circuit 105. Entered.
The absolute position detection resolution is determined by the bit pattern formed on the slit plate.
The amplifier circuit 105 amplifies the analog electric signal output from the photodiode 104 and outputs the amplified signal to the shaping circuit 106.
The shaping circuit 106 shapes the signal output from the amplifier circuit 105 and outputs the signal to the arithmetic unit 107 as a digital gray code signal indicating the absolute position according to the rotation angle of the rotary slit plate 103.
The arithmetic unit 107 performs arithmetic correction based on the absolute position signal output from the shaping circuit 106, converts the absolute position value based on the detection resolution of the slit plate into an equivalent value at a different detection resolution, and outputs the converted value. Details of the resolution calculation correction will be described later with reference to FIG.
The interface 108 outputs a signal representing the position detection result to an external application or the like based on the output of the calculation unit 107.

The “absolute position detecting means” in the present invention corresponds to a portion including the LED 101 to the photodiode 104 in FIG.
Further, the “calculation means” corresponds to the calculation unit 107 in FIG.

  Here, in order to facilitate understanding of the present invention, a conventional absolute encoder will be described.

FIG. 18 is a functional block diagram of a conventional absolute encoder.
The configuration of the absolute encoder shown in FIG. 18 is substantially the same as that shown in FIG. 1, except that there is no arithmetic unit.

FIG. 19 shows an image of a rotary slit plate (corresponding to the rotary slit plate 1803 in FIG. 18) used in the absolute encoder.
In a rotary slit plate used for an absolute encoder, a bit pattern representing an absolute position according to a rotation angle is formed by a slit as shown in FIG. Since the bit string output by the slit pattern at a specific angular position is always unique, the current rotational position of the rotating slit plate can be uniquely identified by examining the bit pattern of light that has passed through the rotating slit plate. Is done.

An index indicating how finely the absolute encoder can detect the rotational position is referred to as “resolution”. The resolution depends on the fineness of the slit pattern of the rotary slit plate. That is, if the slit slit plate is equally divided into 1024 along the rotating direction of the rotary slit plate and different slit patterns are assigned to the respective positions, the rotary slit plate can express a resolution of 1024 (upper left in FIG. 19).
Similarly, if the rotary slit plate is equally divided into 720 pieces along the circumferential direction of the rotary slit plate, the rotary slit plate can express the resolution of 720 (upper right in FIG. 19).
As described above, since the slit pattern is usually determined according to the resolution, the resolution of the absolute encoder is different if the slit plate is different. However, when the resolution value has a multiple relationship, a plurality of resolutions can be expressed by a single rotating slit plate.
For example, the rotary slit plate shown in the upper right of FIG. 19 is assigned with a unique slit pattern every 0.5 degrees. However, if every other absolute position is counted, the same rotary slit plate can be used with a resolution of 360. Can also be obtained (lower right of FIG. 19).

  It should be noted that FIG. 19 is an image diagram and does not show an accurate slit pattern.

FIG. 20 is a list of bit patterns representing absolute positions in a conventional absolute encoder.
As shown on the left side of the table in FIG. 20, in order to express the resolution 1024 with a slit pattern, the slit pattern needs to output information for 10 bits. As shown in the table, when the slit pattern outputs “1”, it indicates that the absolute position of the rotation angle is at a position corresponding to “1” in the resolution 1024. The same slit pattern can be used to express resolution 512, resolution 256, resolution 128, resolution 64, and resolution 32.
Further, as shown on the right side of FIG. 20, in order to express the resolution 720 with a slit pattern, the slit pattern needs to output information for 10 bits. However, as described with reference to FIG. 19, it is necessary to use a slit pattern different from the resolution 1024.
As shown in the table, when using the resolution 720, the value obtained by subtracting 152 from the output value of the slit pattern is the actual absolute position. Similarly, 76 is subtracted when resolution 360 is used, and 38 is subtracted when resolution 180 is used.

FIG. 21 is an image diagram when the list of FIG. 20 is applied to an actual slit pattern.
As shown in FIG. 21, if all the slit patterns are fully used, the maximum resolution can be obtained, and if only a part of the same slit pattern is used, the resolution is reduced by the unused bit width. be able to.
As described above, a plurality of resolutions can be obtained with the same slit pattern, but the obtained resolution depends on the number of bits, and thus is limited to a value having a multiple relationship.

FIG. 22 illustrates a code conversion procedure for obtaining a final output value based on the list of bit patterns described in FIG.
In general, since the output of the absolute encoder is output as a gray code, it is necessary to perform code conversion in order to obtain a binary code or BCD code (binary decimal code) that is easy to process.
For example, when obtaining a BCD code, the BCD code can be obtained by once converting the Gray code into a binary code and then converting it into a BCD code. As described with reference to FIG. 20, when the resolution 720, the resolution 360, and the resolution 180 are used, it is necessary to perform a predetermined subtraction.

Note that the terms “binary system” and “angle system” shown in FIG. 22 will be supplemented here.
The resolution of “binary system” refers to the resolution 32 to resolution 1024 shown in FIG. 22, but there are applications in which it is desirable to output a power of 2 so that it can be easily processed by a computer or the like. It is provided to do.
On the other hand, the resolution of the “angle system” means that, for example, when a human wants to check the rotation angle, such as indexing, binary notation is inconvenient, so the absolute position is determined using a 360 degree angle system. It is provided so that it can be expressed.
Since the slits used differ in the resolution between the two, in the conventional absolute encoder, one of the resolution systems is selected at the time of manufacture, and the slit pattern is formed.
The absolute encoder according to the present invention enables both resolution systems to be expressed by a single slit pattern.

  Hereinafter, the absolute encoder according to the first embodiment will be described.

FIG. 2 illustrates an example of a correspondence relationship when the calculation unit 107 of FIG. 1 performs calculation correction and converts the absolute position value at the resolution 1024 into the corresponding value at the resolution 360.
The arithmetic correction here refers to converting the output value of the slit pattern into a corresponding value at a different resolution when, for example, a slit pattern with a resolution of 1024 is used.
For example, since the absolute position “256” at the resolution 1024 corresponds to a quarter of the resolution value, the position is the same as the absolute position “90” at the resolution 360.
Therefore, when expressing the resolution 360 using a slit pattern with a resolution of 1024, the calculation unit 107 converts the value by the calculation correction as described above, and outputs the converted value. By doing in this way, it becomes possible to express the resolution which could not be expressed conventionally by using the single slit pattern.

FIG. 3 illustrates a processing flow when the calculation unit 107 of FIG. 1 performs calculation correction as illustrated in FIG. Hereinafter, each step will be described.
(S301)
The arithmetic unit 107 performs a predetermined initialization process. For example, processing such as clearing a memory area used for calculation corresponds to the processing in this step.
(S302)
The calculation unit 107 reads the resolution setting to be output. The setting may be stored in advance in a separately provided memory area, or may be fixedly written in the calculation unit 107 at the time of manufacture according to the type of the rotary slit plate 103. However, note that in this case, the types of resolution that can be expressed are limited.
(S303)
The arithmetic unit 107 proceeds to one of the following steps S304 or S306 depending on the type of resolution to be output.
(S304)
The arithmetic unit 107 reads the absolute position signal output from the shaping circuit 106.
(S305)
The calculation unit 107 performs calculation correction as illustrated in FIG. 2, and converts the absolute position signal read in step S304 into a value corresponding to the output resolution. Details of the conversion calculation will be described later with reference to FIG.
(S306)
The arithmetic unit 107 reads the absolute position signal output from the shaping circuit 106.
(S307)
The calculation unit 107 performs calculation correction as illustrated in FIG. 2, and converts the absolute position signal read in step S306 into a value corresponding to the output resolution.
(S308)
The arithmetic unit 107 performs conversion processing between the binary code and the gray code. Which of the binary code and the gray code is used as the final output value may be arbitrarily determined according to the application.
It should be noted that this step is omitted when the code system of the final output value is used at each step.
(S309)
The calculation unit 107 outputs the calculation correction result to the interface 108.
(S310)
The calculation unit 107 determines whether or not the calculation should be ended by the end of the operation of the absolute encoder main body or the like. When continuing the calculation, the process returns to step S303.

FIG. 4 shows an image diagram when a microcomputer is used as one implementation example of the calculation unit 107 of FIG.
When the calculation unit 107 is realized using a microcomputer, the input value of each bit signal before conversion is assigned to each terminal on the input side, and the output value of each bit signal after conversion is assigned to each terminal on the output side. Good.
Note that the implementation method of the arithmetic unit 107 is not limited to a microcomputer, and may be realized by using an arbitrary programmable logic controller (PLC) or the like.

FIG. 5 shows a functional block diagram when a microcomputer circuit as shown in FIG. 4 is used as the arithmetic unit 107 in FIG.
The LED 501, fixed slit plate 502, rotating slit plate 503, photodiode 504, amplifier circuit 505, shaping circuit 506, and interface 508 correspond to the corresponding portions in FIG.
The microcomputer circuit 507 corresponds to the calculation unit 107 in FIG.
The microcomputer circuit 507 includes a calculation unit such as a microcomputer shown in FIG. 4 and its peripheral circuits, and has a memory 509 and a CPU 510.
The CPU 510 is calculation means for performing calculation correction, and for example, a microcomputer as shown in FIG. 4 can be used.
The memory 509 stores a correspondence table 511. Details of the correspondence table 511 will be described later with reference to FIG.

FIG. 6 illustrates the configuration of the correspondence table 511 in FIG. 5 and is used when the calculation unit 107 performs calculation correction in steps S305 and S307 in FIG.
The microcomputer circuit 507 refers to the correspondence table 511 when performing the arithmetic correction processing shown in the flowchart of FIG.
In the correspondence table 511, the relationship between the output value (absolute position) of the rotary slit plate 503 and the corresponding converted value is recorded.
The table on the left side of FIG. 6 shows a list of output values when a slit plate having a resolution of 1024 is used as the rotary slit plate 503, and 1024 values from absolute positions “0” to “1023” are stored. Yes.
The table on the right side of FIG. 6 stores values after conversion when 1024 values on the left side are converted into corresponding values at a resolution of 180. For example, the value “256” in the left table corresponds to a quarter position of the whole, and this corresponds to “45” that is a quarter of 180 in the resolution 180, so “45” is stored in the corresponding position.
Since the value “1023” on the left side corresponds to the position that has just been rotated once and returned to the detection origin, “0” is stored as the corresponding value in the table on the right side.

The correspondence relationship as shown in FIG. 6 can also be obtained from the calculation formula shown in the central part of FIG. 6, but whether or not the fraction should be discarded depends on the circumstances of the individual application. As long as the capacity of the memory 509 and the access speed are allowed, it is desirable to provide a correspondence table as shown in FIG.
6 illustrates a correspondence table in the case of converting the resolution 1024 value into the resolution 180 value. However, if a plurality of other resolution values are desired, a plurality of corresponding tables may be provided. .

FIG. 7 illustrates the correspondence between decimal numbers, binary codes (binary codes), and gray codes. A correspondence relationship as shown in FIG. 7 exists between the respective code systems.
In step S308 of FIG. 3, it is necessary to convert the binary code and the gray code to each other as necessary. The binary code and the gray code both represent corresponding decimal values, but the correspondence can be easily obtained.

  FIG. 8 illustrates a procedure for converting a binary code and a gray code into each other.

To obtain the corresponding gray code from the binary code, follow the procedure below.
(1)
Read the binary code bit string before conversion to gray code.
(2)
The bit string of the binary code before conversion is shifted to the right by one.
(3)
An exclusive OR operation is performed on each bit of the bit string before conversion and the bit string in step (2). The obtained bit string is a corresponding Gray code.

In order to obtain the corresponding binary code from the gray code, the following procedure is taken.
(1)
Reads the bit string of Gray code before conversion to binary code.
(2)
The most significant bit of the bit string in step (1) is used as the most significant bit after conversion.
(3)
An exclusive OR operation is performed on the second bit of the original bit string and the first bit of step (2). Let the obtained value be the value of the second bit after conversion.
(4) to (9)
Thereafter, the same processing is repeated.

In step S308 of FIG. 3, the calculation unit 107 performs the above calculation and performs mutual conversion between binary code and gray code.
Thereafter, the calculation unit 107 performs the process of step S309, and outputs a binary code or a gray code indicating the absolute position after the calculation correction to the interface 108.

As described above, according to the absolute encoder according to the first embodiment,
Absolute position output means for detecting an absolute position according to the rotation angle of the rotating body based on a predetermined first detection resolution and outputting a signal representing the absolute position;
Based on the signal output by the absolute position output means, an absolute encoder comprising a calculation means for outputting position information of the rotating body,
The calculation means performs calculation correction based on the signal output based on the first detection resolution by the absolute position detection means,
Since an equivalent value in the second detection resolution corresponding to the detection value using the first detection resolution is output,
With one absolute encoder, a plurality of types of resolution outputs can be obtained.

A storage unit that stores a correspondence table between an output value at the first detection resolution and a corresponding value at the second detection resolution;
When the calculation means outputs the corresponding value of the first detection resolution in the second detection resolution,
Since the correspondence table stored in the storage means is referenced and the corresponding value is output,
Even when a fraction is generated by the calculation correction of the calculation unit 107, whether or not the fraction should be rounded down can be determined in advance. Further, if the values of the correspondence table 511 are reset or a plurality of correspondence tables are provided, the same processing can be performed for a plurality of resolutions.

The absolute position output means includes
Since it is configured using a slit plate formed with a bit pattern representing the absolute position according to the rotation angle of the rotating body,
Based on the slit pattern of the rotating slit plate, the absolute position with respect to the rotation angle can be detected.

Embodiment 2. FIG.
FIG. 9 is a functional block diagram of an absolute encoder according to the second embodiment of the present invention.
The configuration of the absolute encoder shown in FIG. 9 is the same as that shown in FIG. 5 except that the microcomputer circuit 907 receives the “origin reset” signal from an external application or the like.
When the microcomputer circuit 907 receives the “origin reset” signal from an external application or the like, the microcomputer 907 resets the absolute position of the rotary slit plate 903 at that time as the origin in the subsequent absolute position detection.

FIG. 10 illustrates the advantage of resetting the origin.
In the initial state shown in the left diagram of FIG. 10, when the absolute position according to the angle is detected using the position indicated by the arrow as the detection origin, the initial origin moves from the initial position after the detection ends. When detection is resumed from the same position, detection is performed from an output value other than “0”.
As a result, it is necessary for the user to return the origin position to the original location or to subtract the absolute position at the start of detection from the obtained value, thereby reducing usability.
Thus, if an arbitrary absolute position can be set as the detection origin, such as resetting the absolute position at the end of the previous detection as the detection origin at the start of the next detection, the convenience for the user is increased.

  For example, when the microcomputer circuit 907 receives the “origin reset” signal at the absolute position “109”, the subsequent detection of the absolute position is performed by regarding the position “109” as the absolute position “0”. This is convenient for the user (see the right figure in FIG. 10).

  In addition, the ability to set an arbitrary detection origin is advantageous for the manufacturer. The advantages for the manufacturer will be described with reference to FIG.

FIG. 23 is a diagram for explaining the operation when the origin of the rotary slit plate is aligned in the manufacturing process of the absolute encoder.
Since the absolute encoder is used to detect the absolute position with respect to the rotation angle, the initial origin alignment is very important. This is because if the origin position is deviated, a difference occurs between the detected value and the actual position.
In the actual manufacturing process, the “rotary shaft” shown in FIG. 23 is fixed with a dedicated tool (jig), and the “origin mark” shown in FIG. 23 is provided in accordance with the reference mark of the dedicated tool (jig) and this. The rotating slit plate is rotated so as to coincide with the position of the reference line, and alignment is performed by visual confirmation or the like.
When the position is matched, the position is fixed with an adhesive or the like at the position, and the process proceeds to a solidification process with the position fixed.

  If an arbitrary position can be set as the origin position even after manufacturing, the time-consuming manufacturing process described with reference to FIG. 23 can be omitted, and the manufacturing cost and the efficiency of the period can be improved. There are significant advantages for manufacturers.

The arbitrary detection origin is set by storing the absolute position when the microcomputer circuit 907 receives the “origin reset” signal shown in FIG. 9 in the memory 909, and in the subsequent absolute position detection, the calculation process of the CPU 910 is performed. The position value may be subtracted from the detection result and output.
However, since it is necessary to simultaneously perform conversion conversion correction of resolution, it is more convenient to rewrite the value of the correspondence table 911 when receiving the “origin reset” signal, because it is not necessary to perform complicated calculation at the time of detection. is there.
The values in the correspondence table 911 after rewriting will be described with reference to FIG.

FIG. 11 illustrates a processing flow when the microcomputer circuit 907 in FIG. 9 performs arithmetic correction as exemplified in FIG.
The flowchart shown in FIG. 11 is substantially the same as the flowchart shown in FIG. 3 except that the origin setting is read in step S1102. Further, since the origin resetting may always be performed, it is necessary to read the origin position every time, and the return position of step S1110 is different from FIG.
The origin setting in step S1102 is the absolute position when the microcomputer circuit 907 receives the “origin reset” signal. For example, the absolute position value is stored in an empty area of the memory 909 and read in step S1102 That's fine.
As shown in FIG. 12 described later, when the correspondence table 911 is rewritten based on the reset origin position, it is not necessary to read the origin setting in step S1102.

FIG. 12 explains the configuration of the correspondence table 911 in FIG. 9, and is used when the microcomputer circuit 907 performs calculation correction in steps S1105 and S1107 in FIG.
The correspondence table in FIG. 12 has the same configuration as the correspondence table shown in FIG.
However, when the microcomputer circuit 907 receives the “origin reset” signal, the value of the correspondence table 911 can be rewritten.
For example, as shown in the right diagram of FIG. 10, when the microcomputer circuit 907 receives the “origin reset” signal at the absolute position “109”, the corresponding position in the right table of FIG. Rewrite each value in the right table.
If this rewriting is performed, the microcomputer circuit 907 simply reads the correspondence table 911 and outputs the corresponding value, so that the resolution conversion based on the new origin position is performed alone, so that the origin setting is performed in step S1102 of FIG. The process of reading can be skipped.

  Note that when the “origin reset” signal is received and the right table of FIG. 12 is rewritten, a new value may be obtained using the calculation formula shown in the center of FIG.

As described above, according to the absolute encoder according to the second embodiment,
The arithmetic means receives a signal to set the detection origin of the absolute position of the rotating body,
Since the position corresponding to the output signal of the absolute position output means at the time of receiving the signal is set as a new detection origin,
Arbitrary absolute position can be set as the detection origin, and there is no need for the user to return the origin position to the original location or subtract the absolute position at the start of detection from the obtained value. Increase.
Furthermore, in the manufacturing process, the process of aligning the origin can be omitted, and the manufacturing cost and the period can be improved, which has a great merit for the manufacturer.

Further, when the calculation means receives a signal to set the detection origin of the absolute position of the rotating body,
Since the position corresponding to the output signal of the absolute position output means at the time of receiving the signal is used as a new detection origin, the value of the correspondence table is rewritten,
It is not necessary to read the origin setting each time and perform a calculation such as a subtraction process, and the load on the calculation unit can be reduced.

Embodiment 3 FIG.
FIG. 13 is a functional block diagram of an absolute encoder according to the third embodiment of the present invention.
The absolute encoder shown in FIG. 13 has the same configuration as that shown in FIG. 9, but the microcomputer circuit 1307 outputs a signal indicating the current resolution to an external application or the like, or sends a signal for setting the resolution to the external application. 9 is different from the configuration of FIG.

FIG. 14 shows the contents of the correspondence table 1311 in FIG.
In addition to the configuration shown in FIG. 12, the correspondence table 1311 shown in FIG. 14 is provided with an area (“resolution mode” portion in FIG. 14) for storing a resolution value to be used when performing calculation correction of resolution. Is different.

  The right table of FIG. 14 stores values after resolution conversion corresponding to the values in the area shown in the “resolution mode” of FIG. For example, if “180” is stored in the area shown in the “resolution mode” in the figure, the corresponding value when the resolution 1024 is converted to the resolution 180 is stored in the right table of the figure.

When the microcomputer circuit 1307 receives a signal indicating that the current resolution value should be output from an external application or the like, the microcomputer circuit 1307 reads the value in the area shown in “resolution mode” in FIG. 14 and outputs the value. To do.
Furthermore, when a signal for setting a new resolution is received from an external application or the like, the value of the area shown in the “resolution mode” of FIG. 14 is changed to the value and shown in the center of FIG. A new value corresponding to the resolution is set in the right table of FIG. 14 using the calculation formula.

If the resolution of the rotary slit plate 1303 and the value of the area shown in the “resolution mode” of FIG. 14 are different, the microcomputer circuit 1307 corrects the calculation using the correspondence table 1311 of FIG. In this case, the output value of the slit pattern is output as it is without performing calculation correction.
By doing so, it is possible to avoid performing unnecessary calculation resources by performing the calculation process until it is not necessary to perform calculation correction.

FIG. 15 shows an image diagram when the absolute encoder according to the third embodiment is connected to an external application.
The absolute encoder shown in FIG. 15 outputs a current absolute position signal with respect to the rotation angle to the display device 1502.
The microcomputer circuit 1501 is a microcomputer circuit included in the absolute encoder according to the third embodiment, and corresponds to the microcomputer circuit 1307 in FIG.
The display device 1502 is an external application and displays the current absolute position with respect to the rotation angle.
In the current position display unit 1503, FIG. 15 shows the current absolute position. At the time of display, a value corresponding to the resolution currently used by the absolute encoder is displayed.
The reset signal transmission button 1504 is used to transmit the “origin reset signal” shown in FIG. 13 to the microcomputer circuit 1501 when pressed.
Each time the resolution setting button 1505 is pressed, a “resolution mode” signal shown in FIG. 13 is transmitted. For example, a signal indicating that “resolution should be set to 180” is transmitted to the microcomputer circuit 1501 when pressed for the first time, and a signal indicating that “resolution should be set to 180” is transmitted when pressed for the second time. What is necessary is just to comprise.
A resolution display unit 1506 displays the current resolution setting of the microcomputer circuit 1501. The display can be updated by performing processing such as reading from the microcomputer circuit 1501 every time the user presses the resolution setting button 1505.

Thus, if a signal indicating the current resolution is transmitted to an external application or the like, the user can know the current resolution by visual confirmation or the like, and the convenience for the user is increased.
Furthermore, by receiving a signal indicating that a resolution value should be set and updating the contents of the correspondence table 1311, it is possible to provide an arbitrary resolution desired by the user with a single slit pattern.

As described above, according to the absolute encoder according to the third embodiment,
The storage means stores information indicating a value of resolution to be used as the second detection resolution when the calculation means performs the calculation correction,
The calculation means performs the calculation correction when the resolution value indicated by the information is different from the first detection resolution value.
It is possible to avoid unnecessary calculation resources from being consumed by performing calculation processing even when calculation correction is not necessary.

Further, the calculation means receives a signal for setting information indicating the resolution value and stores the signal in the storage means,
When receiving a signal indicating that the information should be output, the information is read out from the storage means and output.
If a signal indicating the current resolution is transmitted to an external application or the like, the user can know the current resolution by visual confirmation or the like, and the convenience for the user is increased.
Furthermore, by receiving a signal indicating that a resolution value should be set and updating the contents of the correspondence table 1311, it is possible to provide an arbitrary resolution desired by the user with a single slit pattern.

Embodiment 4 FIG.
The absolute encoder according to the fourth embodiment of the present invention is obtained by realizing the portion including the LED 101 to the photodiode 104 in the first to third embodiments with a magnetic sensor or the like.

FIG. 16 is a functional block diagram of the absolute encoder according to the fourth embodiment.
The absolute encoder shown in FIG. 16 includes a rotating magnet 1601 and a sensor unit 1602 that serves as both a magnetic sensor and a detection circuit.
The other configuration is the same as that of the absolute encoder shown in FIG.
As shown in FIG. 16, even when an absolute position with respect to the rotation angle of the rotating body is detected using a magnetic sensor or the like, a plurality of resolutions are realized by calculation correction using the same configuration as in the first embodiment. Can do.

FIG. 17 shows a configuration corresponding to the third embodiment, in which the portion composed of the LED 1301 to the photodiode 1304 in FIG. 13 is configured using the rotating magnet 1601 and the sensor unit 1602 similar to those in FIG.
The absolute encoder shown in FIG. 17 includes a rotating magnet 1701 and a sensor unit 1702 that serves as both a magnetic sensor and a detection circuit.
Other configurations are the same as those of the absolute encoder shown in FIG.
As shown in FIG. 17, even when the absolute position with respect to the rotation angle of the rotating body is detected using a magnetic sensor or the like, a plurality of resolutions are realized by calculation correction using the same configuration as in the third embodiment. Can do. The same applies to the second embodiment.

As described above, according to the absolute encoder according to the fourth embodiment,
The absolute position output means includes
Since it is configured using a magnet that rotates according to the rotating operation of the rotating body, a magnetic sensor that detects the magnetism of the magnet, and a detection circuit that converts the detection value of the magnetic sensor into an electrical signal.
Even when the absolute position with respect to the rotation angle of the rotating body is detected using a magnetic sensor or the like, the same effects as in the first to third embodiments can be obtained.

1 is a functional block diagram of an absolute encoder according to Embodiment 1. FIG. The correspondence relationship when the calculation unit 107 performs calculation correction and converts the resolution will be described by way of example. A processing flow when the calculation unit 107 performs calculation correction as illustrated in FIG. 2 will be described. As an implementation example of the calculation unit 107, an image diagram in the case of using a microcomputer is shown. The functional block diagram at the time of using a microcomputer circuit like FIG. 4 as the calculating part 107 is shown. The structure of the correspondence table 511 in FIG. 5 will be described. This explains the correspondence between decimal numbers, binary codes (binary codes), and gray codes. It is an explanation of a procedure when a binary code and a gray code are mutually converted. FIG. 6 is a functional block diagram of an absolute encoder according to the second embodiment. This explains the advantage of resetting the origin. The processing flow when the microcomputer circuit 907 in FIG. 9 performs arithmetic correction as illustrated in FIG. 2 will be described. The structure of the correspondence table 911 in FIG. 9 will be described. FIG. 9 is a functional block diagram of an absolute encoder according to a third embodiment. The contents of the correspondence table 1311 in FIG. 13 are shown. FIG. 10 shows an image diagram when the absolute encoder according to the third embodiment is connected to an external application. FIG. 10 is a functional block diagram of an absolute encoder according to a fourth embodiment. A portion composed of the LED 1301 to the photodiode 1304 is configured using a rotating magnet 1601 and a sensor unit 1602. The functional block diagram of the conventional absolute encoder is shown. An image of a rotary slit plate used in an absolute encoder is shown. It is the list of the bit pattern showing an absolute position in the conventional absolute encoder. It is an image figure at the time of applying the list of FIG. 18 to an actual slit pattern. A code conversion procedure for obtaining a final output value will be described based on the list of bit patterns described in FIG. In the manufacturing process of the absolute encoder, an operation state when the origin position of the rotary slit plate is aligned will be described.

Explanation of symbols

101 LED, 102 Fixed slit plate, 103 Rotating slit plate, 104 Photo diode, 105 Amplifying circuit, 106 Shaping circuit, 107 Operation unit, 108 Interface, 501 LED, 502 Fixed slit plate, 503 Rotating slit plate, 504 Photo diode, 505 Amplifier circuit, 506 shaping circuit, 507 microcomputer circuit, 508 interface, 509 memory, 510 CPU, 511 correspondence table, 901 LED, 902 fixed slit plate, 903 rotating slit plate, 904 photodiode, 905 amplification circuit, 906 shaping circuit, 907 Microcomputer circuit, 908 interface, 909 memory, 910 CPU, 911 correspondence table, 1301 LED, 1302 fixed slit plate, 1303 rotating slit plate, 1304 photo diode 1305 Amplifier circuit 1306 Shaping circuit 1307 Microcomputer circuit 1308 Interface 1309 Memory 1310 CPU 1311 Corresponding table 1501 Microcomputer circuit 1502 Display device 1503 Current position display section 1504 Reset signal transmission button 1505 Resolution setting Button, 1506 Resolution display unit, 1601 Rotating magnet, 1602 Magnetic sensor and detection circuit, 1605 Amplifying circuit, 1606 Shaping circuit, 1607 Calculation unit (microcomputer circuit), 1608 interface, 1609 Memory, 1610 CPU, 1611 Corresponding table, 1701 Rotating magnet 1702 Magnetic sensor and detection circuit, 1705 amplifier circuit, 1706 shaping circuit, 1707 microcomputer circuit, 1708 interface, 1709 memory, 1710 CPU, 711 correspondence table, 1801 LED, 1802 fixed slit plate, 1803 rotary slit plate, 1804 photodiodes, 1805 amplifying circuit, 1806 shaping circuit, 1808 interface.

Claims (6)

The absolute position corresponding to the rotation angle of the rotating body is detected based on the first detection resolution predetermined, the absolute position output means for outputting a signal representing the absolute position,
Storage means for storing a correspondence table between output values at the first detection resolution and corresponding values at the second detection resolution;
A calculation means for outputting the corresponding value with reference to the correspondence table stored in the storage means when outputting the corresponding value of the first detection resolution in the second detection resolution;
The storage means stores information indicating a resolution value to be used as the second detection resolution,
When the information is received and the value of the resolution that is the information is different from the value of the first detection resolution, the calculation means determines the second detection resolution according to the resolution value. An absolute encoder that calculates and corrects the corresponding value . The arithmetic means receives a signal to set the detection origin of the absolute position of the rotating body,
Absolute encoder according to claim 1, at the time of accepting the signal, the position corresponding to the output signal of the absolute position output means, and sets a new detection origin. When the calculation means receives a signal to set the detection origin of the absolute position of the rotating body,
3. The absolute encoder according to claim 2 , wherein a value corresponding to the output signal of the absolute position output means at the time when the signal is received is used as a new detection origin to rewrite the value in the correspondence table. The calculation means receives a signal for setting information indicating the resolution value and stores the signal in the storage means. When receiving a signal to output the information, the calculation means receives the information from the storage means. 4. The absolute encoder according to claim 1 , wherein the absolute encoder is read and output. The absolute position output means includes
Absolute encoder according to any one of claims 1 to 4, characterized in that it is constructed using the slit plate formed with a bit pattern indicating the absolute position corresponding to the rotation angle of the rotating body. The absolute position output means includes
The magnet is configured to rotate in accordance with a rotating operation of a rotating body, a magnetic sensor that detects magnetism of the magnet, and a detection circuit that converts a detection value of the magnetic sensor into an electric signal. The absolute encoder according to any one of claims 1 to 4 .

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