JPH0894387A - Rotating direction detector for rotary encoder - Google Patents

Abstract

PURPOSE: To correctly detect the rotating direction of the rotary shaft of a rotary encoder. CONSTITUTION: When one or the other of a pair of pulses output from a rotary encoder is changed, data DOLD indicating the change is stored. When the one or the other of the pair of pulses is changed, the relationship between the data DNEW indicating the latest change and the stored data DOLD is checked. As a result of the check, when the relationship between the data DNEW and DOLD is one relationship (1), (2), the data DIRF indicating that the rotating direction of a rotary shaft is clockwise is output. As the result of the check, when the relationship is the other relationship (3), (4), the data indicating that the rotating direction of the shaft is counterclockwise is output. As the result of the check, when the relationship between the data DNEW and DOLD is the residual other relationship, the pair of pulses are ignored.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotation direction detecting circuit for a rotary encoder which is controlled by a user's knob operation.

[0002]

2. Description of the Related Art A rotary encoder is generally used when a user turns a knob to select a letter such as an alphabet or a number as the knob is turned.

Then, in the rotary encoder, as shown in FIG. 6, two-phase pulses A and B are output and a knob (rotating shaft) of the rotary encoder is used.
When the knob is turned clockwise CW, the pulse A has a phase advanced from the pulse B, and when the knob is turned counterclockwise CCW, the pulse A has a phase delayed from the pulse B.

Therefore, the rotation direction of the knob can be detected from the phase relationship between the pulse A and the pulse B. In other words, the rotation direction of the knob is clockwise CW if A = "H" at the rising edge of pulse B
When turned to, if A = “L” at the rising edge of pulse B, then turn counterclockwise.
It was when I turned it to CCW.

Further, when the click function is added to the rotation of the knob, the position of the vertical broken line in FIG. 6 may be set as the stop position (click position) of the knob. That is, by doing so, one pair of pulses A and B is generated for each click.
Is output.

As shown in FIG. 7, for the rotary encoder which outputs a pair of pulses for each click,
Furthermore, if you set the stop position of the knob with the position of the vertical chain line,
There can be one pair of pulses for every two clicks. In other words, in this case, the knob rotation direction is clockwise CW if A = "H" at the rising edge of pulse B
When A = "L" at the falling edge of pulse B, turn clockwise CW
When turned to, if A = “L” at the rising edge of pulse B, then turn counterclockwise.
When turned to CCW If A = "H" at the falling edge of pulse B, turn counterclockwise
It is when turning to CCW.

As described above, in the case of FIG.
Since one pulse is provided for each click, the number of pulses A and B per unit rotation angle can be small, and in the rotary encoder, the cams for the switches that form the pulses A and B can be simplified accordingly.

[0008]

However, in the rotary encoder of the pulse which outputs one pair for every two clicks, the knob is not properly turned. For example, when the knob is turned as shown by an arrow X in FIG. If the target stop position θ0 is passed too far and then returned to the stop position θ0, the edge position θX of the pulse B passes in the clockwise direction CW even though the original rotation of the knob is CCW in the counterclockwise direction. , The knob is identified as the clockwise CW rotation, resulting in a false detection.

The present invention is intended to solve such a problem.

[0010]

FIG. 4 is an enlarged reprint of FIG. 7 and shows pulses A and B in FIG.
More specifically, assuming that the section in which the pulses A and B are “1” (angle range of knob) is 2θ, the period of the pulses A and B is 5θ, and the phase difference between the pulses A and B is θ. Also, as indicated by the broken line, A = “H” and B = “H”
The center position of the rotation angle position is the stop position of the knob, and as shown by the chain line, A = “L” and B
The center position of the rotation angle position where "L" is also the stop position of the knob.

In the following description, as shown in FIG. 4, the rising edge of the pulse A, the falling edge of the code A ↑ pulse A, the rising edge of the code A ↓ pulse B, and the rising edge of the code B ↑ pulse B are referred to. The trailing edge is represented by the symbol B ↓.

Of the waveform changes A ↑ to B ↓ of the pulses A and B obtained when the knob is turned, attention is paid to the latest two waveform changes, and the latest waveform changes are PNEW and the previous one. If the waveform changes are POLD, these waveform changes PNE
There are 16 combinations of W and POLD shown in FIG.

However, of these 16 combinations,
A combination of waveform changes marked with X in the judgment column cannot occur.

Further, the combination of waveform changes described as NOP in the judgment column has no meaning. For example, the second P
OLD = A ↑, PNEW = A ↓ corresponds to the case where the knob is moved back and forth at the angular position where the pulse A changes, but this is to move the knob in small steps back and forth between adjacent stop positions. It is an operation and a meaningless knob operation.

The combinations of waveform changes marked by in the judgment column correspond to the cases of in FIG. 4 and correctly indicate the rotation direction of the knob.

The present invention has been made paying attention to the above points so that the rotary direction of the rotary shaft of the rotary encoder can be correctly detected.

That is, in the present invention, when the reference numerals of the respective parts correspond to the embodiments described later, a pair of pulses A and B having different phases are output according to the rotation of the rotary shaft, and the rotary shaft is rotated. Corresponding to the rotation direction of 1
When one or the other of the pair of pulses A and B changes in the detection circuit that detects the rotation direction of the rotary shaft, the rotary encoder 1 in which the phase advance / delay relationship of the pair of pulses A and B is reversed, The relationship between the memory 23 for storing the data DOLD indicating the change, the data DNEW indicating the latest change when one or the other of the pair of pulses A and B changes, and the stored data DOLD. When the relationship between the data DNEW indicating the latest change and the stored data DOLD is one as a result of this check,
Data DI indicating that the rotation direction of the rotation axis is clockwise
When the relation between the data DNEW indicating the latest change and the stored data DOLD is another relation as a result of outputting RF, and the stored data DOLD is another relation, the rotation direction of the rotation shaft is counterclockwise. The data DIRF indicating that is output, and as a result of the check, when the relation between the data DNEW indicating the latest change and the stored data DOLD is the other remaining relation,
The pair of pulses A and B are ignored.

[0018]

Even if the knob or the rotary shaft moves back and forth at a position other than the stop position, the output at that time is ignored and the rotation direction is correctly detected.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, reference numeral 1 denotes a rotary encoder, which has two switches 1A and 1B, and these switches 1A and 1B are pulled up by resistors RA and RB. Further, although not shown, a cam is provided on the rotary shaft of the rotary encoder 1, and the cam controls ON / OFF of the switches 1A and 1B according to the rotation of the rotary shaft. The above-mentioned pulses A and B are extracted from the pull-up point of.

The pulses A and B from the rotary encoder 1 are supplied to the microcomputer 2. The microcomputer 2 stores the waveform changes PNEW and POLD of the pulses A and B, and determines the combination of the combinations PNEW and POLD to detect the rotation direction of the rotary shaft of the rotary encoder 1.

Therefore, the microcomputer 2 has a C
It has a PU 21, a ROM 22 in which programs are written, a RAM 23 for a work area, and the like.
As a part of the program, the detection routine 10 shown in FIG. Also,
Data indicating waveform changes POLD and PNEW
When OLD and DNEW are set, the RAM 23 secures addresses for storing these data DOLD and DNEW.

When the level of the pulse A or B from the encoder 1 changes (when an edge occurs in the pulse A or B), the processing of the routine 10 proceeds to step 11.
Then, in step 12, the data DNEW when the routine 10 was executed last time is transferred to the data DOLD (the data DOLD is rewritten by the data DNEW and DOLD = DNEW).

Then, in step 13, the pulse A that triggered the execution of this routine 10 this time.
Alternatively, the B waveform change (this is the waveform change PNEW) is stored as data DNEW. It should be noted that this data DNEW will be used as the data DOL in step 12 as described above when the routine 10 is executed next time.
Transferred to D.

Next, in step 14, data DOLD
And the data DNEW are checked, and when corresponding to or in the judgment column in FIG. 5, the process proceeds from step 14 to step 15, and this step 15
At, the direction flag DIRF indicating the rotation direction of the rotary shaft of the rotary encoder 1 is set to a value indicating the clockwise direction CW, for example, "L", and then this routine 10 is ended at step 17.

In step 14, the data DOL
When the relationship between D and the data DNEW corresponds to or in the judgment column in FIG. 5, the process proceeds from step 14 to step 16, and in this step 16, the direction flag DIRF indicates a value indicating the counterclockwise CCW, for example, CCW. "H"
Is set to, and thereafter, this routine 10 is ended at step 17.

Further, in step 14, the data D
When the relationship between OLD and the data DNEW does not correspond to any of the judgment columns in FIG. 5, the process proceeds from step 14 to step 17, and this routine 10 is ended.

Therefore, in the routine utilizing the output of the rotary encoder 1, the direction of rotation of the rotary shaft of the rotary encoder 1 can be known using the direction flag DIRF set in step 15 or 16.

Thus, according to this detection circuit, in the rotary encoder 1 which outputs a pair of pulses for every two clicks, the rotation direction can be correctly detected without stopping the knob properly at the stop position. .
Moreover, for that purpose, it is only necessary to execute the routine 10, and since the routine 10 can be executed as a part of the processing program in, for example, a microcomputer for system control,
There will be no cost increase.

Further, as shown in FIG. 3, for example, even if chattering occurs in the pulses A and B, the chattering portion is ignored, so that the rotation direction can be correctly detected. Further, as shown by an arrow X in FIG. 3, even if the knob is moved back and forth at a position other than the stop position, this will not be erroneously detected.

Although the rotary encoder 1 is composed of the switches 1A and 1B and the cam in the above description, it may be composed of, for example, two photo interrupters and a light shielding plate provided on the rotating shaft.

[0031]

According to the present invention, 1 is provided for every 2 clicks.
In the rotary encoder 1 that outputs a pair of pulses, the rotation direction of the rotary encoder 1 can be correctly detected without stopping the knob properly at the stop position. Moreover, for that purpose, only the routine 10 needs to be executed, and since this routine 10 can be executed as a part of another processing program, the cost does not increase.

Further, even if chattering occurs in the pulses A and B, the chattering portion is ignored, so that the rotation direction can be correctly detected.

[Brief description of drawings]

FIG. 1 is a connection diagram showing an example of the present invention.

FIG. 2 is a flowchart showing an example of the present invention.

FIG. 3 is a waveform diagram showing an operation example of the present invention.

FIG. 4 is a waveform diagram for explaining the present invention.

FIG. 5 is a characteristic diagram for explaining the present invention.

FIG. 6 is a waveform diagram for explaining a conventional example.

FIG. 7 is a waveform diagram for explaining a conventional example.

FIG. 8 is a waveform diagram for explaining a conventional example.

[Explanation of symbols]

 1 rotary encoder 2 microcomputer 10 detection routine

Claims (3)

[Claims] 1. A pair of pulses whose phases are different from each other are output according to the rotation of the rotating shaft, and the lead / lag relationship of the phase of the pair of pulses is inverted corresponding to the rotating direction of the rotating shaft. In the detection circuit for detecting the rotation direction of the rotary shaft, the one of the pair of pulses changes or the other changes,
A memory for storing data showing the change, and when one or the other of the pair of pulses changes,
The circuit has a circuit for checking the relationship between the latest data and the stored data, and as a result of this check, the data showing the latest change,
When the relationship with the stored data is one, data indicating that the rotation direction of the rotary shaft is clockwise is output, and as a result of the above check, the data indicating the latest change is displayed. ,
When the relation with the stored data is another relation, data indicating that the rotation direction of the rotary shaft is counterclockwise is output, and as a result of the check, the latest change is displayed. Data shown,
A rotation direction detection circuit for a rotary encoder, which ignores the pair of pulses when the relationship with the stored data is the other relationship. 2. When the pair of pulses are pulses A and B, as a result of the check, the data showing the latest change shows the rising of the pulse B, and the stored data is the stored data. In the case of the relationship showing the rising of the pulse A, or in the case where the data showing the latest change shows the falling of the pulse B and the stored data has the relationship showing the falling of the pulse A, Data indicating that the rotation direction of the rotary shaft is clockwise is output, and as a result of the above check, the data indicating the latest change indicates the rise of the pulse A, and the stored data indicates the pulse B. Or the data indicating the latest change indicates the trailing edge of the pulse A, and the stored data indicates the pulse. When the relationship shown a fall of the rotation direction of the rotating shaft to output data indicating the counter-clockwise direction, of the check result, the data representing the most recent change,
When the stored data indicates another rising and falling relationship of the pulses A and B,
The rotation direction detection circuit of the rotary encoder according to claim 1, wherein the pulses A and B are ignored. 3. A rotary encoder rotation direction detection circuit according to claim 1, wherein one pair of the pair of pulses is output every two clicks.