JP2010048786A - External adjustment type encoder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To secure reliability of signal adjustment by preventing an encoder from being operated without prescribed signal adjustment, and to realize essential performance of the encoder. <P>SOLUTION: In this external adjustment type encoder equipped with a scale 10, a detection head 20 displaceable relatively to the scale 10, and a communication means 36 with the outside, capable of signal adjustment by an external device (personal computer 50) connected to the communication means 36, execution of signal adjustment of an amplitude, an offset and a phase difference in a detection signal on a plurality of sine waves detected following relative displacement of the detection head 20 to the scale 10 is stored in a memory 38, and when the signal adjustment is not executed yet, position information from the encoder is inputted and reported to a control device 46 for performing feedback control. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an externally adjustable encoder that includes a scale, a detection head that can be displaced relative to the scale, and an external communication unit, and is capable of signal adjustment by an external device connected to the communication unit. In particular, the present invention relates to an externally adjustable encoder suitable for use in linear encoders, rotary encoders, linear gauges and the like, which can easily know whether or not signal adjustment is performed.

  In devices that require position and speed control, such as machine tools, linear encoders, rotary encoders, and the like are generally used as feedback sensors.

  The linear encoder and the rotary encoder are composed of a scale and a detection head that can be displaced relative to the scale. In particular, in a separate type encoder illustrated in FIG. 1 (FIG. 1 is an example of a linear encoder), the scale 10 and the detection head 20 are separated and assembled to the apparatus in a predetermined positional relationship, and then the oscilloscope 60 and the like. The signal adjustment is generally performed by the above. In FIG. 1, 22 is a cable and 24 is an output connector.

  On the other hand, the inventor has proposed an externally adjustable encoder capable of performing signal adjustment by an external device such as a personal computer 50 without using an oscilloscope as shown in FIG.

With this externally adjustable encoder,
(1) A / D conversion is performed on the output of the detector 30 made of, for example, a photoelectric element by an A / D converter 32;
(2) The CPU 34 captures this A / D conversion result,
(3) A / D conversion data (raw data) is transmitted to the external device (personal computer 50) by the communication means 36,
(4) The error (correction data) calculated by the external device (the personal computer 50) is taken into the CPU 34 by the communication means 36,
(5) Save the acquired correction data in the memory 38,
(6) After correcting the signal by the error correction circuit 40 using the acquired correction data,
(7) Interpolation by the interpolation circuit 42,
(8) The communication means 44 outputs to the control device (for example, servo amplifier) 46.

  According to this method, strict signal adjustment is possible without using signal confirmation means such as an oscilloscope.

Japanese Patent Laying-Open No. 2006-3307 (FIGS. 6 and 8)

  However, even with such an externally adjustable encoder, signal adjustment after assembling to the device should be performed as long as position detection is possible within a signal state that is not detected by an alarm detection circuit such as a signal abnormality. Therefore, even if the correction data is not updated to the optimum value after installation, it does not cause an error and it is unknown whether or not the optimum adjustment has been made (whether or not the predetermined performance and accuracy have been realized). There is a problem that accuracy is deteriorated due to an error, or a sufficient margin until error detection cannot be secured.

  The present invention has been made to solve the above-mentioned conventional problems, and prevents the encoder from operating in a state where the predetermined signal adjustment is not performed, thereby ensuring the reliability of the signal adjustment and the original performance of the encoder. It is a problem to realize.

  The present invention relates to an externally adjustable encoder that includes a scale, a detection head that can be displaced relative to the scale, and an external communication unit, and is capable of signal adjustment by an external device connected to the communication unit. , The presence or absence of signal adjustment of amplitude, offset, and phase difference in a plurality of sinusoidal detection signals detected as the detection head is displaced relative to the scale is stored in memory, and signal adjustment is not performed In this case, the above-mentioned problem is solved by inputting position information from the encoder and notifying a control apparatus that performs feedback control.

  Here, the memory stores the presence / absence of the amplitude adjustment and the presence / absence of the offset / phase difference adjustment separately, and stores the signal when the amplitude adjustment, the offset and the phase difference adjustment are not performed. Inform the control device that it has not been adjusted, and when the amplitude adjustment is only performed and the offset and phase difference adjustments are not performed, inform the control device that the offset and phase difference adjustments have not been performed. Can do.

  According to the present invention, it is possible to confirm whether or not signal adjustment has been performed by the output of the encoder. Therefore, it is possible to prevent the encoder from being operated without performing signal adjustment. In addition, when the signal adjustment is not performed, the control device is informed, so there is no state where the predetermined performance is not obtained or the state where the adjustment error is large, the reliability of the signal adjustment is ensured, and the original performance of the encoder is improved. Can be realized.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  In the first embodiment of the present invention, as shown in FIG. 3, an adjustment execution flag is provided in the memory 38 in the linear encoder having the same configuration as that of the conventional example shown in FIG. This makes it possible to know whether or not adjustment has been performed.

  The adjustment execution flag is cleared in the initial state, and is set by a signal adjustment execution command from the personal computer 50.

  Hereinafter, the operation will be described with reference to FIG.

  When the power is turned on in step S1, it is checked in step S2 whether the adjustment execution flag in the memory 38 is set. If the signal is not adjusted in the factory shipment state and the adjustment execution flag is not set by the signal adjustment execution command from the personal computer 50, the process proceeds to step S3, and the signal unadjusted error signal is sent via the communication means 44. The data is output to the control device 46 by serial communication. As a result, an error is displayed on the control device 46 side, and signal adjustment using the personal computer 50 is performed.

  On the other hand, when the adjustment execution flag is set in step S2 and it is determined that the signal has been adjusted, normal operation is started in step S4.

  If it is desired to use the encoder with high accuracy, strict signal adjustments such as (1) signal amplitude, (2) offset, and (3) phase difference are necessary. The system cannot be operated without adjusting the encoder signal. However, in signal adjustment, (1) if only signal amplitude adjustment can be performed, it is possible to make the system operable even if the accuracy of the encoder cannot be compensated.

  Therefore, in the second embodiment of the present invention, as shown in FIG. 5, two kinds of flags “adjustment execution flag A” and “adjustment execution flag B” are provided in the memory 38 as signal adjustment flags, and the communication means 44 is provided. Through the serial communication, the CPU 34 outputs a “signal unadjusted error” (state where the signal is not adjusted) signal or a “signal unadjusted warning” (state where only the signal amplitude is implemented) to the control device 46. From this, a function for enabling the gain setting to the detector 30 and adjusting at least the state in which the system operates is provided.

  The adjustment execution flags A and B remain cleared when the signal is not adjusted in the factory shipment state.

  Hereinafter, the operation will be described with reference to FIG.

  When the power is turned on in step S11, it is determined in step S12 whether or not an adjustment execution flag A indicating that the amplitude adjustment as temporary adjustment has been completed is set.

  If it is determined in step S12 that the adjustment execution flag A is not set, the process proceeds to step S13, and a signal unadjusted error signal is output to the control device 46 via the communication means 44 by serial communication. Next, in step S14, a signal adjustment execution command is transmitted from the control device 46, and signal amplitude adjustment (gain setting) as exemplified in FIG. 7 is executed. Here, the signal amplitude of the linear encoder at an arbitrary point can be adjusted by setting the gain of the signal.

  After step S14 ends, in step S15, a signal adjustment execution command is transmitted from the personal computer 50, and the adjustment execution flag A is set.

  After step S15, or when it is determined in step S12 that the adjustment execution flag A has already been set, the process proceeds to step S16, and it is confirmed that strict signal adjustment such as offset and phase difference, which is full-scale adjustment, has been performed. It is determined whether or not the adjustment execution flag B shown is set. If the determination result is NO and the amplitude adjustment has been completed but the strict signal adjustment such as offset and phase difference has not been completed, the process proceeds to step S17, and the signal unadjusted warning signal is transmitted via the communication means 44. Then, the data is output to the control device 46 by serial communication, and if necessary, signal adjustment is performed by the personal computer 50, a signal adjustment command is transmitted from the personal computer 50, and the adjustment execution flag B is set.

  After step S17 is completed, or when it is determined that the determination result in step S16 is positive and the adjustment execution flag B is set, the process proceeds to step S18 and the normal operation is started.

  In the present embodiment, when the adjustment execution flag A is not set, the amplitude is adjusted by communicating with the control device 46, so that the adjustment can be automatically performed at least until the system operates.

  Furthermore, if it is possible to automatically adjust the system to operate, all other signal adjustment items that require movement of the linear encoder can be automatically adjusted, and signal adjustment is performed. You can eliminate the state that is not.

  In each of the above embodiments, the signal unadjusted error signal and warning signal are output to the control device 46 via the communication means 44 by serial communication. However, the signal unadjusted error signal and warning signal are directly output. It is also possible to configure to input to the control device 46. In this case, since the signal unadjusted error signal and the warning signal are directly connected to the error signal input terminal of the control device, there is an advantage that it can be used without changing the program in the serial communication between the control device 46 and the linear encoder.

  In the above-described embodiment, the linear encoder has been described as an example. However, the application target of the present invention is not limited to this, and the present invention can be applied to a rotary encoder, a linear gauge, and the like in addition to the linear encoder. .

The perspective view which shows an example of the state which is performing signal adjustment with a separate type linear encoder Block diagram showing the configuration of an externally adjustable linear encoder proposed by the inventor in Patent Document 1 The block diagram which shows the structure of 1st Embodiment of this invention. Flow chart showing the same effect The block diagram which shows the structure of 2nd Embodiment of this invention. Flow chart showing the same effect The figure which similarly shows the signal amplitude adjustment method

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Scale 20 ... Detection head 30 ... Detector 32 ... A / D converter 34 ... CPU
36, 44 ... Communication means 38 ... Memory 40 ... Error correction circuit 42 ... Interpolation circuit 46 ... Control device

Claims (2)

A scale, a detection head capable of relative displacement with respect to the scale, and an external communication means;
In an external adjustment type encoder capable of signal adjustment by an external device connected to the communication means,
Stores in a memory whether or not to perform signal adjustment of amplitude, offset, and phase difference in detection signals on a plurality of sine waves detected as the detection head is displaced relative to the scale,
An externally adjustable encoder characterized in that, when signal adjustment is not performed, position information from the encoder is input to notify a control device that performs feedback control. The memory stores the presence / absence of amplitude adjustment and the presence / absence of offset and phase difference adjustment separately,
When neither amplitude adjustment nor offset and phase difference adjustment is performed, the control device is informed that the signal is not adjusted, only amplitude adjustment is performed, and when offset and phase difference adjustment are not performed, The external adjustment type encoder according to claim 1, wherein the control device is informed that the phase difference adjustment is not performed.

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