JPS60169709A - Scale reading and counting device - Google Patents

Abstract

PURPOSE:To make it possible to divide a general purpose-digital scale into multiple parts and to read the scale at a high speed, by providing a circuit, which divides the pitch of the scale coarsely and counts the divided parts, a circuit, which divides the inside of the pitch finely and counts interpolated values, and a circuit, which detects the speed of displacement. CONSTITUTION:When a length X is measured, a starting point Ps is located at a position separated by M1 from a coarse divided point of a scale signal, which has passed at the last time. The value of M1 is read at the time of measurement by a phase modulation dividing method and memorized. Then, by the displacement along the scale, a scale signal in a sine waveform is detected. The number (n) of pulses, which are generated every time the coarse dividing point is passed is counted and stored. At a final point Pe of the measurement, the value M2 from the coarse dividing point, which is passed at the last time, is read by the phase modulation dividing method. Depending on whether the signal from a speed detecting circuit 5 is at a high speed or at a low speed, carry-out and carry-down pulse signals are made to be a B signal from a coarse system (b) or to be an A signal from a fine system (a). This is selected by an A.B signal-switching circuit 12. The measured counted value is displayed based on the counted values stored in a counted (n) pulse value memory circuit 9 and an M1.M2 memory circuit 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a device that electrically divides the graduations of a digital scale into multiple parts, reads them at high speed, and displays them digitally.

In known methods of reading digital scales, the number of divisions in one pitch (P) and the reading speed are in a mutually contradictory relationship, and when the number of divisions is increased, it is inevitable that the reading speed will be limited. . The present invention provides a scale reading device that does not cause reading errors even when the scale is divided into multiple parts and the moving speed is high.

Originally, a digital scale generates a periodic signal at a fixed pitch and measures the length by counting the signals, but the width of this pitch is limited by processing techniques such as mwl. In order to obtain the required minimum reading value, this pitch is generally divided using electrical means. The methods for this division include: ■ The zero-crossing method that divides the two-phase signal into four; ■ The two-phase signal is calculated using resistors and electrically converted to a multiphase signal, and each zero-crossing method generates a pulse. A phase modulation division method in which a carrier wave is phase-modulated with a scale signal and this phase difference is counted using a clock pulse is known. When the number of divisions is relatively small, for example 10 to 20, it is possible to count and display all the pulses obtained using a conventional division method using a counter, but it is not possible to do so with high accuracy. Reduce the minimum reading value for measurement,
When increasing the number of divisions, there are limits to the processing time for division and the response speed of the counter, and there is a problem that high-speed measurement without counting errors is not possible within 8 meters. In order to solve these problems, the applicant first filed a patent application No. 57-2029.
No. 4 has been filed for a patent regarding the scale reading method. This is equipped with a fine thread that divides one pitch of the digital scale into many parts and counts it, and a coarse counter that counts the number of pitches, and detects the moving speed of the scale.
This method involved switching input and storing count signals from coarse and fine yarn counters, and outputting and displaying the measured distance based on the calculated values of both.

However, in the above invention, since coarse counting is performed for each pitch, if the scale pitch is not at the end of Y (for example, in the case of a decimal counter, 1.0+=10.102
= 100, etc.) There was a drawback that it was not easy to carry up or down the display of the upper digits of the counter.

In practice, scales of 10μ pitch, 20μ pitch, etc. are often used in the spring.

The present invention solves this problem and is applicable to most of the scale pitches and minimum reading values of display counters that are used in practical use, so counting in the coarse system is not performed for each pitch, The present invention provides a general-purpose multi-division high-speed reading and counting device that generates pulses at points where one pitch is divided into several parts and counts the pulses. The present invention will be described in detail below, but the present invention is not limited thereto.

FIG. 1 shows the basic concept of the present invention.

When measuring the length X, the measurement starting point Ps is located at an arbitrary position on the scale, and in the figure it is located at a position M from the coarse division point of the last passed scale signal. This value of Ml can be read using the phase modulation division method described above. This MI is read and stored at the beginning of the measurement. Then, by displacing along the scale, a sin waveform scale signal is detected, and a pulse is generated every time it passes through a coarse division point obtained by dividing the pitch of the scale into N. This number of pulses (n) is counted and stored.

At the end point (Pe) of the measurement, similarly to the starting point, the value M2 from the coarse division point passed last is read using the phase modulation division method and the measurement is completed. With this, we can know the amount of displacement
Rice. However, if the displacement is at a low speed that the operating speed of the phase modulation dividing circuit and the calculation processing speed described above can sufficiently handle, the above calculation will not be performed only at the end of the measurement, but will follow the displacement moment by moment. It is also possible to calculate and display using the counted value n of the fine thread M2. An embodiment of the circuit configuration of the present invention is shown in FIG.

It is added to the phase modulation coarse division (m division) circuit of the system.

Here, by the above-mentioned phase modulation division method, a pulse signal proportional to the amount of displacement within one pitch of the scale signal is outputted every period of si old 1. This pulse signal has the following ρ/I
The 11 division value counting circuit performs a fresh count every 5inu+t, and in this embodiment, the final count is p.
/m digit display signal. At the start of measurement, a measurement starting point setting signal is applied from the outside, and the contents of this p/m division value count are stored in the memory circuit. On the other hand, p
The output of the /tn division circuit goes into the carry/carry/down pulse signal generation circuit, and in the case of Y base display, the Y of the p/m division value
A pulse signal is generated for each count and sent as an A signal to a carry/carry/down signal switching circuit.

Here, the scale pitch P is roughly divided by the number N obtained by dividing the scale pitch P by Y in the Y-adic counter. As a dividing method, any of the above-mentioned methods such as (1) zero-cross method, (2) resistance division method, (2) phase modulation division method, etc. may be used.

Then, the number is counted by the next p/n division value counting circuit,
Then, it becomes a pulse signal in the carry/carry-down pulse generation circuit and enters the carry/carry-down switching circuit as a B signal.

Furthermore, the signal from the scale also enters the speed detection circuit to detect the displacement speed, and the signal is sent to the A and B signal switching circuit. If the displacement speed is faster than a predetermined limit, the AB signal switching circuit is set to pass the B signal, that is, the carry/carry/down pulse signal from the coarse division circuit.
The signal is counted by the next n-pulse counting circuit.

In the case of low speed, the A signal of the fine thread is similarly counted by the N pulse counting circuit. In this way, the values stored in the M and M2 storage circuits at the start and end of measurement and the current value stored in the n-pulse count value storage circuit at α are led to the counting operation display circuit, and simple addition and subtraction calculations are performed to display the results. The amount of displacement can be known by displaying it on the display section.

However, during high-speed movement, the phase modulation division method does not indicate the correct value as described above, so the carry-up and carry-down pulse signals of the fine thread are unreliable.As a result, the reading accuracy at high speed is 1 pitch in this embodiment. However, when moving at high speed, the counted value on the precision side constantly changes and cannot be read visually, so it is not a practical problem. Generally, when a scale is moved for measurement, even if the scale moves at high speed in the middle, it stops or moves at very low speed at the start and end points of the measurement. Even if the speed increases during intermediate movement and an error occurs in the fine thread carry/carry/down signal A, the precision side counting circuit is a 7 retouch counter, so when the speed becomes low at the end point, it will return to the correct value again. Since it can be shown, there is no problem, and this is a major feature of the present invention.

Next, a specific example of count display using the above circuit configuration will be explained. FIG. 3 shows the case where the scale pitch is 20 and the minimum reading value is 0.1 μm in decimal notation. P
s and Pe are the starting point and ending point of measurement, respectively. In the fine thread, the 20 ym pitch scale signal shown in (a) in the figure is divided into 200 by a phase modulation multi-division circuit as shown in (b) and counted, to obtain the memorized values of Ml and M2. . In the multi-division circuit for fine thread, since this example uses the decimal system, the pitch of 20μ is divided into two to create 10μ.
Make sure that a carry/carry/down pulse signal is obtained for each carry/carry/down pulse signal.

(E) indicates a speed detection signal, and a switching circuit selects whether the carry/carry count signal is the B signal from the coarse system or the A signal from the fine thread depending on whether the speed is high or low. (to) Count n pulses and memorize them, M
I, M2 Displays the constant value count.

As another example, if the scale pitch is 201ff and the IIS minimum reading value is O, Jg+++, decimal system, for fine yarn, the pitch 2J+m is divided into 40 to obtain a value of 0.5 μm, and this is counted and coarsened. In the system, since it is a decimal system, the above-mentioned scale pitch 2 can be achieved by dividing 20 decimals into two and generating a carry up/down pulse for every 10 tones.
0-1 minimum reading 0. Exactly the same signal as lpm
This can be carried out by counting and calculation processing.

Similarly, the minimum reading value is 0.5 with a scale pitch of 25
-, pinch 25, JIll in the fine thread multi-division circuit
divided by 50 and 0. ! This is possible by generating a signal obtained by dividing the pitch 25IIIn into five in the coarse system, and outputting a carry/carry/down pulse every second of this signal. However, in this case, it is necessary to add a circuit that outputs one pulse for every two count inputs to the coarse carry/carry down pulse signal generation circuit shown in FIG. If counting is required to be displayed in decimal notation, the structure of the present invention can be achieved by selecting and setting the scale pitch, number of fine thread divisions, and coarse division number to match the minimum reading value and the decimal notation. It becomes possible to implement.

By the way, even if the signals are from the same scale as in the device of the present invention, if this is divided into two systems, fine and coarse, and these are selected by a switching circuit for counting, calculation, and display, the precision The pulse generation positions of the rough surface system do not necessarily coincide both dimensionally and temporally, which causes counting errors and eventually measurement errors. For example, if the generation point of the carry-over carry-down signal due to coarse division and the generation point of the fine thread carry-over carry-down signal due to phase modulation multi-division are shifted, errors such as not counting or double counting may occur.

Regarding this counting error prevention device, the applicant filed a patent application in 1973.
A patent application has been filed under No. 7-138147. In order to prevent counting errors at the time of switching from coarse to fine yarn or from fine yarn to coarse yarn, the generation point of the coarse system division signal is used as one boundary, and the area is divided into three or more areas. The area including the part immediately after the pulse generation point is defined as area 1, the area other than the pulse generation point and area is defined as area H, and the content of the fine thread counter that counts the division value within 1 pitch. Similarly, divide the count value 0 into three or more areas with the count value 0 as one boundary, the area containing the count value O as the area 1, the area containing the maximum count value as the area ■, and the areas other than ■ and ■. is the area of ■, and the area of ■ changes to the area of Counting errors are prevented from occurring at the time of switching by incrementing the carry/carry count by 1 when the count value changes from 1 to area ■ and vice versa. It is characterized by this.

If the above-mentioned counting error prevention device is used together with the device of the present invention,
Highly accurate count display without miscounts can be performed.

As detailed above, according to the device of the present invention, high-speed multi-division (micro-reading) reading of digital scales, which has been considered impossible, can be achieved with a simple circuit configuration and the pitch and minimum reading of most practical scales. It can be applied universally to values.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of a reading method using the apparatus of the present invention, FIG. 2 is a block diagram showing an example of the circuit configuration of the present invention, and FIG. 3 is an explanatory diagram of input/output signals in the circuit configuration example of the present invention. 6 Patent Applicant Tokyo Seimitsu Co., Ltd.

Claims (1)

[Claims] In a digital scale reading and counting device that outputs periodic signals in response to displacement, there is a circuit that roughly divides the pitch of the scale as a coarse system and counts it, and a fine thread that divides the pitch of the scale on the fine side and calculates the interpolated value. and a speed detection circuit for the displacement obtained by the scale, and
A circuit for storing the count value M0 from the immediately preceding coarse dividing point obtained from the fine thread cutter at the starting point l of displacement, and the count value M2 from the immediately preceding coarse dividing point obtained from the fine thread cutter at the end point of displacement; The carry-carry-carry-down pulse signal B obtained from the dividing point and the carry-carry-carry-down pulse signal A generated for each count value corresponding to the coarse division width of the coarse system obtained from fine thread are determined by whether the displacement is high or low. A scale reading/counting device comprising: a switching circuit for switching output according to the switching circuit; a circuit for counting and storing the number n of switching circuit output signals; and a circuit for calculating and displaying the amount of displacement from each of the counted and stored values.