JPH095116A - Absolute encoder - Google Patents

Abstract

(57) [Summary] [Purpose] To facilitate product management and adjustment of absolute pattern read timing when timing adjustment is performed using incremental signals. [Constitution] An absolute encoder has an encoder main body and a feedback board section connected to this main body via a connection cable, and the encoder main body has an absolute detection means, an incremental detection means,
A signal detector equipped with a signal selection circuit and a parallel-serial conversion circuit is installed, timing information for switching the absolute detection means is displayed on the encoder body with an identification sticker, and the feedback board unit is provided with an arithmetic processing circuit, A switching signal generation circuit for reading an absolute pattern and a signal generation setting means are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absolute encoder. More specifically, the present invention relates to a new absolute encoder that facilitates product management and adjustment of absolute pattern read timing when timing is adjusted using an incremental signal.

[0002]

2. Description of the Related Art An absolute encoder is a measuring instrument that outputs position information of a detector with respect to a code plate by using an absolute position signal unique to each relative position. In this absolute encoder, the code plate and the detection unit are combined so as to be movable relative to each other, and the detection unit is provided with a sensor for discriminating the physical information of the pattern. As such an absolute encoder, there are a conventionally known multi-track type and a one-track type, and in recent years, the latter track-type has been put into practical use.

This one-track type absolute encoder includes, for example, as shown in the example of FIG. 2, one track absolute pattern of a minimum reading unit λ and a code plate on which an incremental pattern of a pitch λ is formed, and two sets. Absolute detector (E1-E4, F1-F
4), a detector including an incremental signal detecting element (S1, S2) having an element for an incremental signal and detecting an incremental pattern, and a signal selection circuit,
It is composed of a parallel-serial conversion circuit.

The incremental pattern is used after being interpolated in order to improve the position resolution. In addition, the absolute encoder may cause a pattern reading error when the sensor passes through the boundary area of the minimum reading unit of the absolute pattern.Therefore, adjust the timing when the sensor reads the absolute pattern to avoid the boundary area. In order to perform reading, the element group in the boundary area of the absolute pattern and the element group in the minimum reading unit of the absolute pattern are constantly switched, and the signal for that is generally generated by the incremental pattern. The signal is being used. Furthermore, in a practical encoder, the number of bits of the absolute pattern may exceed n = 10. Therefore, in order to reduce the number of signal lines from the detector, a parallel-serial conversion circuit that serially outputs a signal is used. Is also provided, and a device for forming the circuit in the sensor IC is also made. Regarding the device for reading the absolute pattern in the boundary area and the incorporation of the serial output circuit into the sensor IC, the applicant of the present invention discloses Japanese Patent Application Laid-Open Nos. 2-168115, 4-296017, and Three
The means disclosed in Japanese Patent Publication No.-295413 is also proposed.

The switching timing signal for reading the absolute pattern is determined by monitoring the absolute pattern signal and the incremental pattern signal with an oscilloscope or the like and adjusting the variable resistance, the switching switch or the like provided in the switching signal generating circuit to determine the switching timing signal. Become.

[0006]

On the other hand, in general, when a linear encoder is used in a machine tool or the like, the structure of the encoder is, for example, as shown in FIG. 3, a code plate, a signal detector, a connecting cable, and A feedback board section (incorporated in a control device or the like), a control circuit is mounted on the feedback board, and the feedback board section on which the signal detector and the control circuit are mounted is separate. That is, the main part of the electric circuit for signal processing is placed on the feedback board part. Therefore, in order to prevent the reading error of the absolute signal, if the timing is adjusted using the incremental signal,
For subsequent product management, it was necessary to handle the encoder body (consisting of the code plate and the detector) and the feedback board unit as a pair. In addition, when either the encoder body or the feedback board unit fails and is replaced, read-out timing of the absolute pattern must be readjusted in the feedback board unit while monitoring the encoder body signal. Therefore, there is an inconvenience that the adjustment work is troublesome.

Therefore, the present invention solves the conventional problems as described above, and it is not necessary to manage the encoder main body and the feedback board section in pairs, and it is easy to set the absolute pattern read timing. The purpose is to provide an absolute encoder.

[0008]

In order to solve the above-mentioned problems, the present invention sets an absolute pattern read timing to an incremental pattern obtained at the time of signal adjustment in an absolute encoder using a signal of the incremental pattern. Display the positional relationship information of the absolute pattern on the encoder body,
The feedback board unit is provided with a setting function for switching the signal based on the information and fixing the timing.

That is, according to the present invention, a code plate on which an absolute pattern having a minimum reading unit length of λ and an incremental pattern having a pitch of λ are formed, and a code plate is arranged at a pitch of λ with respect to the absolute pattern. An absolute detection unit including a plurality of first detection units and a plurality of second detection units arranged with a phase difference of 1 / 2λ with respect to the first detection unit, and the incremental pattern is detected to detect 90 degrees. An incremental encoder that outputs two incremental signals having a phase difference of 1., and an absolute encoder that alternately switches the first detector and the second detector of the absolute detector based on the incremental signal. In which the absolute detection means is switched Display information on the encoder body, the feedback substrate portion connected to the encoder main body to provide an absolute encoder, characterized in that remembering setting function of the switching timing.

Further, according to the present invention, in the above absolute encoder, an encoder main body and a feedback board portion connected to the main body via a connection cable are provided, and the encoder main body has an absolute detection means and an incremental detection unit. Means, a signal selection circuit, and a signal detector equipped with a parallel-serial conversion circuit is installed,
The timing information for switching the absolute detection means is displayed on the encoder body with an identification sticker,
The feedback board unit may be equipped with a switching signal generation circuit for reading an absolute pattern and a signal generation setting unit as well as an arithmetic processing circuit.

[0011]

According to the present invention, with the configuration as described above, the adjustment for reading the absolute pattern while avoiding the boundary area of the absolute pattern is performed during the initial signal adjustment process, and the positional relationship between the absolute pattern and the incremental pattern is obtained. By making the encoder main body have the information of, the combination with the feedback board section can be freely set.

Therefore, in the absolute encoder of the present invention, it is not necessary to manage the encoder main body and the feedback board section in pairs, and it becomes easy to set the reading timing of the absolute pattern.

[0013]

Embodiments of the present invention will be described below. Of course, the present invention is in no way limited by this example. FIG. 1 shows an embodiment of the present invention.
As shown in FIG. 1, the absolute encoder includes an encoder body, a connection cable, and a feedback board section.

In the encoder body, the code plate is placed in the encoder body and the signal detector is installed. Then, the signal detector includes an absolute detector and an incremental detector,
It is composed of a signal selection circuit and a parallel-serial conversion circuit. The absolute detection unit includes a plurality of first detection units arranged at intervals of a pitch λ with respect to an absolute pattern having a minimum reading unit length of λ.
It has a plurality of 2nd primary detecting elements arranged with a phase difference of 1 / 2lambda to a primary detecting element. Further, the incremental detection unit detects an incremental pattern having a pitch of λ and outputs two incremental signals having a phase difference of 90 degrees.

With this configuration, it is necessary to perform amplitude adjustment, offset adjustment, etc. on the signal detection unit during assembly, but even in that case, it is not necessary to connect to the feedback substrate unit, and the adjustment tool substrate is used. Can be used. The adjustment work for reading the absolute pattern while avoiding the boundary area of the absolute pattern is also performed during the signal adjustment process. Here, the information necessary to read the absolute pattern while avoiding the boundary area of the absolute pattern is determined in the assembled state of the encoder body regardless of the feedback board section.
In this embodiment, the relationship between the incremental pattern determined by the adjustment and the absolute pattern, that is, the timing information for switching the absolute detection unit is represented by attaching a dedicated identification sticker to the encoder body.

On the other hand, the feedback board section is provided with an arithmetic processing circuit for performing signal processing and also with a switching signal generating circuit for reading an absolute pattern. The switching signal generation circuit is a variable resistor
By using an appropriate setting means such as a changeover switch, a signal for reading an absolute pattern that matches the state of the encoder body can be generated at any timing.

[0017]

As described above, according to the present invention, the adjustment for reading the absolute pattern while avoiding the boundary area of the absolute pattern is performed during the initial signal adjustment process, and the positional relationship between the absolute pattern and the incremental pattern is determined. By displaying the information on the encoder body and allowing the switching signal to be set at an arbitrary timing in the switching signal generation circuit provided in the feedback board section, the encoder body and the feedback board section can be managed independently.

[Brief description of drawings]

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

FIG. 2 is a configuration diagram of an absolute encoder that switches the reading timing of an absolute pattern according to an ink melody signal.

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

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toru Morita 3 2-3 Marunouchi, Chiyoda-ku, Tokyo Inside Nikon Corporation

Claims (3)

[Claims] 1. A code plate formed with an absolute pattern having a minimum reading unit length of λ and an incremental pattern having a pitch of λ, and a plurality of first plates arranged at intervals of a pitch λ with respect to the absolute pattern. An absolute detecting means comprising a detecting portion and a plurality of second detecting portions arranged with a phase difference of 1 / 2λ with respect to the first detecting portion, and the incremental pattern is detected to detect a phase difference of 90 degrees. And an incremental detection means for outputting two incremental signals having, and an absolute encoder for alternately switching the first detection portion and the second detection portion of the absolute detection means based on the incremental signal, Encoder main body provides timing information for switching absolute detection means View and absolute encoder on the feedback board unit connected to the encoder body, characterized in that remembering setting function of the switching timing. 2. The absolute encoder has an encoder main body and a feedback board portion connected to the main body via a connection cable, and the encoder main body has:
A signal detector equipped with an absolute detection means, an incremental detection means, a signal selection circuit, and a parallel-serial conversion circuit is installed, and timing information for switching the absolute detection means is displayed on the encoder body with an identification sticker. 1 absolute encoder. 3. The absolute encoder according to claim 1, wherein the feedback board unit is provided with an arithmetic processing circuit, a switching signal generation circuit for reading an absolute pattern, and a signal generation setting means.