JPS602602B2 - Zero signal generation status identification device for origin signal detection - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device for identifying the generation state of a zero signal for detecting an origin signal in a digital shelf length device such as a linear encoder.

Digital side length devices mainly used for measuring length and positioning stages of machine tools include absolute type and incremental type linear encoders.

In recent years, the absolute position information display of the absolute method,
In order to perform the functions of the incremental method, such as displaying information on the distance traveled from an arbitrary position to a fixed position, with one device, an incremental method digital side length device with an origin signal was developed and started to be used. It has become. In order to detect the origin signal, these are provided with a scale for detecting the origin signal on the pulse scale of the linear encoder and a window corresponding to the scale for detecting the origin signal on the index scale, or a window corresponding to the scale for detecting the origin signal is provided on the pulse scale of the linear encoder. The zero signal for detecting the origin signal is created by roughly matching the IJ mitt switch for detecting the origin signal with the pulse scale.

This origin signal is created by detecting the rising edge of the zero signal for detecting the origin signal using a rising edge detection circuit, and converting the rising edge into a pulse.

In creating the zero signal for origin signal-crow detection described above, the pulse scale and index scale are installed in the former case, and the pulse scale and IJ mitt switch are installed in a predetermined relationship on the machine tool etc. in the latter case. When not, the zero signal for detecting the origin signal is generated in a state that is too long or too short, and when it is attached in a predetermined relationship, the zero signal for detecting the origin signal of a constant length is generated.

That is, in any case, the state in which the zero signal for detecting the origin signal is generated varies depending on how the encoder is attached to the machine tool or the like.

In other words, when attaching one of the '1' pulse scale and the index scale with a window for origin detection to a movable member (such as a stage of a machine) and the other to a fixed part (main body of a machine), the interval between each If the positional relationship and orientation are as designed, the zero signal for home signal detection will have a predetermined (constant) length; if it is not installed as designed, the zero signal for home signal detection will be The width may be longer or shorter than the above-mentioned predetermined length, and similarly [2] If the pulse scale and mitt switch are not installed in the designed positional relationship, the origin signal detection The zero signal does not have a predetermined fixed length.

Below, we will take as an example a linear encoder that has a window in its index scale that corresponds to the scale and pulse scale for detecting the origin signal to create a zero signal for detecting the origin signal. Identification of the generation state of the zero signal for signal detection will be explained based on the drawings.

FIG. 1 is a schematic diagram of a well-known incremental type linear encoder. 1 is the pulse scale and 10
The main scale part lm and the origin detection scale part lz are formed by bright and dark striped lines of about 1.0 m.

There is an index scale 4 at a position slightly spaced apart from the pulse scale 1, and it has two windows 4a and 4b having scales at the same pitch as the main scale part lm.
, and each scale of these two windows 4a and 4b is 1
/4 pips. It has a phase difference of Further, the index scale 4 has an origin detection window 4Z at a position facing the origin signal detection scale portion lz of the pulse scale 1. Light-emitting diodes 6a, 6b, 6z and light-receiving elements 5a, 5b, 5 are mounted on the windows 4a, 4b, 4z, respectively.
As shown in FIG. 1, the scale 1 and the index scale 4 are fixedly stacked so as to sandwich the pulse scale 1 and the index scale 4. Only the pulse scale 1 is attached to a stage of the machine (not shown), so it is movable, and the index scale 4,
The light emitting diode 6 and the receiving/emitting element 5 are installed in the main body of the machine (not shown) and cannot be moved. When the pulse scale 1 and index scale 4 are moved relatively, the main count signals 10a and 10b shown in the upper part of FIG.
, 5b, and 1 occur respectively, so by counting and displaying these, the relative movement amount of both scales can be read.

The main count signals 10a and 10b are converted into rectangular wave signals 11a and 1, respectively.
A pulse train 12 having twice the frequency of the signals 10a and 12b is created by shaping the waveform to 1b and using the rising and falling edges of the signals 11a and 11b.

In addition, when both scales 1 and 4 are moved relatively, the zero signal 10z for origin detection is transmitted from the light receiving element 5 = a to the second
The signal 11z is generated with a waveform as shown in the upper part of the figure, and is shaped into a rectangular wave.

Now, before the linear encoder is attached to the machine, the pulse scale 1 and the index scale 4 are adjusted to a predetermined relationship, and at that time, the zero signal 11z for detecting the origin signal is obtained with a predetermined length. Suppose you are in a state where However, if the pulse scale 1 and index scale 4 are not in the predetermined relationship when the linear encoder is actually attached to the machine body, the zero signal 11z for home signal detection may be longer than the predetermined length as described above. It has been the case that the period has been too long or too short, that is, the generation state has become unstable.

Therefore, when installing a linear encoder on a machine, it is important to check the generation state of the zero signal for home signal detection.
This is important in knowing whether or not the attachment condition of the pulse scale and index scale is in a predetermined relationship.

Since the zero signal for detecting the origin signal is placed at one point within the effective length of the pulse scale 1, or at intervals of, for example, about 5 broadsides, the signal only appears instantaneously and sporadically.

Even if it is observed with an oscilloscope or the like, it cannot be seen as a continuous signal, so it has been difficult to observe the waveform of the momentary signal 11z. Furthermore, a memory type oscilloscope that can store the waveform of the -instantaneous signal 11z for a long time is actually used, but this is very expensive. The above describes not only the encoder which has the scale lz for detecting the origin signal and the window 4z corresponding to it and which creates the zero signal for detecting the origin signal, but also the pulse scale and the IJ mit switch independently of the index scale. The same thing can be said when a zero signal for origin signal detection is created by combining the following.

An object of the present invention is to provide an apparatus that can inexpensively and reliably identify the generation state of a zero signal for detecting the origin signal without observing the waveform with an oscilloscope or the like.

Below, in order to create a zero signal for detecting the origin signal, a linear encoder having a scale for detecting the origin signal in the pulse scale and a window corresponding to the scale for detecting the origin signal in the index scale is used. An example of this will be explained in detail based on the drawings.

The first embodiment will be described based on FIG. 3a. Third
In Figure a, 13 is an up/down counter, into which the pulse train 12 shown at the bottom of Figure 4 is input and counted.

As described above, in the present invention, the rising edge detection circuit 17 detects the rising edge of the zero signal 11z for detecting the origin signal and the hawk S,
A pulse signal r is detected at , and this pulse signal r is set as the origin signal.

The origin signal or pulse signal r is the up/down counter 3
When this happens, the counter 13 is reset to zero.

Therefore, after the pulse signal r is generated, the counter 13 counts the pulse train 12 from the zero-reset state,
The numerical value is sent to the storage circuit 14. Falling detection circuit 1
The value of the up/down counter 13 is held in the memory circuit 14 at the moment a falling pulse is generated from 6. That is, the counter 13 counts the pulse train 12 from the rising position S, and the number of pulses from the rising position S, to the falling position S2 is stored in the memory circuit 14, and this is displayed on the light emitting diode numeric display element 15. .

For example, in this embodiment, when the pulse scale 1 is fed in 100,000 directions, the pulse count value from the rising position S, to the falling position S2 of the zero signal 11z for detecting the origin signal is the fourth
As shown in the figure, when the number reaches 15, it is set that the attachment of the linear encoder to the machine tool etc. has reached a predetermined relationship.

However, when the linear encoder is actually mounted on a machine, if the mounting condition does not meet the predetermined relationship, the pulse count value becomes, for example, 17 or 13, which is either too long or too short than the predetermined value. Therefore, by identifying the generation state of the zero signal for detecting the origin signal, it can be determined whether the mounting condition is in a predetermined relationship or not. As described above, according to this embodiment, the generation state of the zero signal for detecting the origin signal can be detected by simply adding a memory circuit, a fall detection circuit, and a rise detection circuit to the function of the counting circuit, without using a memory display type oscilloscope. can be reliably identified.

Next, a second embodiment will be explained based on FIG. 3b.

As shown in FIG. 3b, the second embodiment uses means instead of the memory circuit 14 used in the first embodiment to identify the generation state of the zero signal for detecting the origin signal.

In this embodiment, the pulse train 12 is input to the up/down counter 13 via the gate circuit 18 and counted.

The rising edge signal of the zero signal 11z for detecting the origin signal is taken out by the rising edge detection circuit 17, and inputted into the S terminal of the set/reset flip-flop circuit 19 to be set. The falling signal of the signal 11z is detected by the falling detection circuit 20 and inputted to the R terminal of the circuit 19 to reset it. The flip-flop circuit 19 causes the gate circuit 18 to input the pulse train 12 to the up/down counter 3 only during a certain period from the rise to the fall of the zero signal 11z for detecting the origin signal. Further, the origin signal pulse r, detected by the rising edge detection circuit 17 resets the up/down counter 13 to zero when it occurs. When the pulse scale 1 is moved in the ten directions, the up/down counter 13 detects the rising position S of the zero signal 11z for detecting the origin signal.
．． Pulse at r. The pulse train 12 from the time when is generated to the time when the pulse h at the falling position S2 of the zero signal 11z for home signal detection is generated is counted, and the value is held and displayed on the light emitting diode numeric display element 15. If this is done, the same effects as in the first embodiment can be obtained in this embodiment. In the above embodiments, the present invention is explained using a linear encoder having a scale for detecting the origin signal in the pulse scale and a window corresponding to the scale for detecting the origin signal in the index scale. Instead, roughly match the limit switch to the pulse scale to detect the origin signal.

The present invention can also be applied to near-encoders that create signals. Furthermore, although the present invention has been described in the above embodiments only with respect to a photoelectric encoder, it goes without saying that the present invention can also be applied to a magnetic encoder.

As described above, according to the present invention, it is possible to provide an apparatus that can inexpensively and reliably identify the generation state of the zero signal for origin signal detection without observation using an oscilloscope or the like.

[Brief explanation of the drawing]

Figure 1 shows a well-known linear linear system. A schematic diagram of the encoder, Figure 2 shows two main count signals related to the device in Figure 1, a zero signal for origin detection, a signal obtained by shaping these three signals into a rectangular wave, and a signal with a frequency twice that of the main count signal. FIG. 3 is a block diagram showing two embodiments of the present invention, and FIG. 4 shows two main count signals shaped into square waves for the apparatus of FIG. 3, which are also shaped into square waves. FIG. 4 is a diagram showing a zero signal for apex detection, a pulse train having twice the frequency of the main count signal, an origin signal, etc. Explanation of symbols of main parts, 1... Pulse scale, lm... Main scale part, 4... Index scale, 4a, 4b... Two windows of index scale, 1
7... Origin signal generation circuit, 13... Skin up/down counter, 14... Memory circuit, 11;, 20
．． ．． ．． ...Fall detection circuit, 19...Set 1
．． 'Set flip-flop circuit, 18...Gate circuit for inputting pulses from the pulse generation circuit outside the counter for a certain period of time, lz...Scale for detecting origin signal;
4z...Back side corresponding to the origin signal detection scale. 1 figure, 2 figures, 3 figures, 4 figures

Claims (1)

[Scope of Claims] 1. A pulse generator having a pulse scale and an index scale opposed to the scale, and outputting a number of pulses according to the amount of relative movement of both scales, and the relative movement of the scale. A zero signal generating device that generates a zero signal for detecting a zero point signal at a predetermined position of the position detecting device, wherein the pulse generating device and the zero signal generating device a counting device that is connected and counts the pulses input while the zero signal is input; and a display device that displays a number of pulses counted by the counting device; An identification device characterized in that the width of the zero signal is known from a display. 2. The identification device according to claim 1, wherein the counting device is reset to zero when the zero signal starts to be generated. 3. In the device according to claim 2, the counting device includes an up-down counter, a memory circuit, and a fall detection circuit that generates a pulse when the zero signal for detecting the origin signal reaches a fall position. The storage circuit stores the counted value of the up-down counter from the pulse generator from the zero reset position to the time when the pulse from the fall detection circuit is generated. An identification device characterized by storing information using pulses. 4. In the device according to claim 2, the counting device includes an up-down counter, a falling detection circuit for detecting a falling signal of the zero signal for detecting the origin signal, and a falling edge detection circuit that is set at the start of generation of the zero signal. and a reset flip-flop circuit which is reset by the signal from the falling detection circuit, and which outputs the pulse from the pulse generator only for a certain period from the rising edge to the falling edge of the zero signal for detecting the origin signal. The up-down counter counts the pulses from the pulse generator from the zero reset position to the falling position of the zero signal for home signal detection and holds the counted value. An identification device characterized by: 5. In the device according to any one of claims 1 to 4, the origin signal detection zero signal generating device includes a origin signal detection scale provided on the pulse scale and the index scale. An identification device characterized in that a zero signal for detecting the origin signal is generated by a combination of the scale for detecting the origin signal provided in the origin signal and a corresponding window.