JP5006752B2 - Displacement detector - Google Patents

Description

  The present invention relates to a displacement detection apparatus for detecting a displacement by processing an analog signal input from a displacement sensor, and particularly suitable for use in scanning measurement using a linear gauge and high-speed response and peak measurement. The present invention relates to a displacement detection apparatus capable of realizing both of the real-time characteristics necessary for the above.

  A displacement detection device for detecting a displacement by processing an analog signal input from a displacement sensor, such as a linear gauge counter, is known.

  For example, as described in Patent Document 1, an analog signal input from the displacement sensor 10 is divided by a dividing / pulsing circuit 22 like a pulse counting circuit 20 illustrated in FIG. There is a pulse counting method in which peak data is obtained by converting into a pulse signal according to the above and counting in real time by the counter IC 24. Here, the applicant has proposed the techniques of Patent Document 2 and Patent Document 3 as generating analog signal interpolated pulses.

  According to this pulse counting method, conversion from an analog signal to a pulse and pulse counting are performed by hardware, so that the real time property is excellent, and a peak position in scanning measurement or the like can be detected in real time.

  However, the higher the resolution, the higher the pulse frequency, and the higher the required performance for hardware. For example, when the resolution is 1 μm and the response speed is 1000 mm / second, the frequency is 1 MHz, when 0.1 μm is 1000 mm / second, the frequency is 10 MHz, when 0.01 μm is 1000 mm / second, the frequency is 100 MHz, and when 0.001 μm is 1000 mm / second. Is 1000 MHz, and according to the current technology, in the submicron region of 0.1 μm or less, it is difficult to realize in terms of cost, power consumption, and noise, and it is difficult to secure a response speed.

  In order to avoid the increase in the frequency band accompanying the increase in resolution in such a pulse counting method, as shown in FIG. 2, the arithmetic circuit 30 is divided into a counter IC 32 for counting the period of the analog input signal and one period. An operation method is also conceivable in which a dividing circuit 34 for counting is separately provided and synthesized by a microcomputer (microcomputer) 36 for output.

JP-A-5-248850 JP-A-8-136280 Japanese Patent Laid-Open No. 10-2759

  However, as shown in FIG. 3, the peak detection of the scanning measurement to the measuring object 8 can be performed in real time according to the pulse counting method shown in FIG. 1, as shown in FIG. In the calculation method shown in FIG. 2, as shown in FIG. 3B, since the data is calculated every calculation cycle, the peak of the measuring object 8 cannot be captured, and real-time detection such as peak measurement of the scanning measurement is performed. It was difficult to deal with applications that required high performance.

  The present invention has been made to solve the above-described conventional problems, and an object thereof is to realize both high-speed response and real-time characteristics necessary for peak measurement.

The present invention provides a displacement detection apparatus for processing an analog signal input from a displacement sensor to detect displacement, a pulse counting means for converting the analog signal into a pulse and counting, a period of the analog signal, and comprises a calculating means for combining measures of data in one cycle separately, and a switching means for outputting the output of said pulse counting means is offset by the output of said arithmetic means, said switching means, normally At the time of measurement, the output of the calculating means is output. At the time of peak measurement, the output of the pulse counting means is offset by the output of the calculating means at the start of peak measurement, and then the output of the pulse counting means is output. Thus , the above-mentioned problems have been solved.

  According to the present invention, high-speed response can be satisfied by the output of the calculation means, and real-time characteristics required for peak measurement can be ensured by the output of the pulse counting means.

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

Implementation form of the invention suitable for use in the peak measurement, as shown in FIG. 4, the conventional example similar to the pulse counting circuit (pulse counting means) 20 shown in FIG. 1, the comparative example shown in FIG. 2 When the normal measurement, the outputs of the counter IC 32 and the dividing circuit 34 of the arithmetic circuit 30 are combined and output as current value data. At the time of peak measurement by scanning measurement, FIG. As shown in Fig. 5, real-time data (broken line) output from the pulse detection circuit 20 with current value data (solid line) output from the arithmetic circuit 30 at the start of peak measurement that clears the peak value by applying the displacement sensor spindle to the measurement object. Is provided with a microcomputer (switching means) 40 that outputs the data as peak data (one-dot chain line).

  Here, the peak value of the peak data is held until it is next cleared.

  The pulse counting circuit 20 has a limit in the moving speed of the displacement sensor 10 that can be followed, and if the overspeed is reached, the reliability of the measured value is lost. However, as in this embodiment, the current value data at the time of resetting the peak measurement start is used. By offsetting the output of the pulse counting circuit 20, highly reliable peak data can be obtained.

  In general, since the displacement of the measurement object around the peak value is small, the pulse counting circuit 20 is overspeed around the peak value and hardly follows.

Before you facilities forms although was suitable to peak measurement, regardless of the presence or absence of peak measurement, the comparative form to be able to obtain a highly reliable real-time data shown in FIG.

In this comparative embodiment, the pulse count circuit 20 is provided with an overspeed detection circuit 26 that detects an overspeed that is difficult to follow the displacement amount and outputs an alarm, and also detects the speed of the current value data in the microcomputer 40. When it is detected by the monitor 42 and the overspeed detection circuit 26 that the overspeed is lost after the overspeed is detected, the current value data of the arithmetic circuit 30 is detected as shown in FIG. And an AND circuit 44 for automatically offsetting the real-time data output from the pulse counting circuit 20 is provided.

According to this comparative embodiment, not only during peak measurement, but also when the overspeed of the displacement amount is detected by the overspeed detection circuit 26 and an alarm is output, real-time data with high reliability is obtained by the speed monitor 42 in the microcomputer 40. It is possible to obtain highly reliable real-time data except until the speed is reduced to the speed at which the data can be obtained.

In this comparative embodiment, the speed monitor 42 separate from the overspeed detection circuit 26 is provided in the microcomputer 40. However, when the overspeed is no longer detected using the output of the overspeed detection circuit 26. It is also possible to offset real-time data.

  The object of application of the present invention is not limited to scanning measurement using a linear gauge, and can be applied to displacement detection in general.

Block diagram showing a conventional pulse counting circuit Block diagram showing a circuit of an arithmetic method of a comparative example The figure for demonstrating the problem of a prior art example and a comparative example Block diagram showing the configuration of implementation of the invention Figure showing operation example Block diagram showing the configuration of the comparison form Figure showing operation example

Explanation of symbols

8 ... Measurement object 10 ... Displacement sensor 20 ... Pulse counting circuit 22 ... Division / Pulsing circuit 24, 32 ... Counter IC
26 ... Overspeed detection circuit 30 ... Arithmetic circuit 34 ... Dividing circuit 36, 40 ... Microcomputer
42 ... Speed monitor

Claims (1)

In a displacement detection apparatus for detecting displacement by processing an analog signal input from a displacement sensor,
Pulse counting means for converting the analog signal into a pulse and counting;
Arithmetic means for separately measuring and synthesizing the period of the analog signal and data within one period;
The output of said pulse counting means and a switching means for outputting the offset at the output of said arithmetic means,
The switching means outputs the output of the computing means during normal measurement, and during peak measurement, the output of the pulse counting means is offset by the output of the computing means at the start of peak measurement, and then the pulse counting means A displacement detection device characterized by outputting an output .

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