JPH02201521A - Method and device for controlling electromagnetic induction type coordinate analyzer - Google Patents

Abstract

PURPOSE:To improve the read precision of a controller by operating the deviation of stop pulse timing between different frequencies of the induction voltage of a coil in accordance with counted values of counters and correcting counted values of counters with corresponding correction values based on this deviation. CONSTITUTION:At the time of measuring the cursor position, the voltage induced in a coil 2 is shaped to two stop pulses 18 and 20 by band-pass filters 10 and 12 different in frequency pass band, and they are supplied to counters 14 and 16 prepared for band-pass filters 10 and 12 respectively. The difference between clock pulse counted values of counters 14 and 16 indicates a phase deviation d between stop pulses 18 and 20 outputted from two band-pass filters 10 and 12, and a correction value corresponding to this deviation is called from a memory, and counted values of counters 14 and 16 are corrected with this correction value. Thus, the read precision is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a control method and apparatus for an electromagnetic induction coordinate analyzer.

[Conventional technology]

An electromagnetic induction coordinate analyzer was developed as a device for placing a cursor equipped with a coil at an arbitrary position on a tablet on which a matrix conductor is arranged, and measuring the X-Y coordinate values of this cursor on the tablet. 50-24571
No. 52-37342 and the like. An electromagnetic induction coordinate analyzer applies pulsed currents with a constant time difference to conductors arranged in a matrix on a tablet at predetermined intervals in the X-axis direction and the Y-axis direction. The control device supplies clock pulses to the pulse counter simultaneously with the start of supply of this pulse current, and the pulse counter starts counting clock pulses. When the cursor coil catches the magnetic field obtained by the pulsed current and an induced voltage is generated in this coil, a counter stop pulse is generated at the point where this voltage first becomes zero, and this counter stop pulse starts the counter clock. Pulskaran 1 - Stops the work. The count value of the counter at this time is used as the coordinate value of the cursor on the tablet.

[Problems to be Solved by the Invention] When the cursor coil catches the magnetic field obtained by the pulse current as described above and stops counting the tallock pulses of the counter for determining the coordinate mill, there are 5 to 10 pulses in the cursor coil. If there are not more than one matrix conductor, the fundamental frequency of the catch voltage of the cursor coil will not be constant, and highly accurate reading will not be possible. As shown in FIG. 6, when the number of matrix conductors 4 in the cursor coil 2 is large, as shown in FIG.
There is almost no variation in the frequency of There was a flaw.

The present invention aims to eliminate the above-mentioned defects.

Means for Solving Problem C] To achieve the above object, the present invention generates an induced voltage in a cursor coil by a magnetic field signal from the tablet side where a matrix conductor is disposed, and uses this induced voltage to control the clock of the counter. In an electric induction type coordinate analyzer that stops the pulse counting operation and counts the position of the cursor on the tablet, it is connected to the coil and divides the coil induced voltage into voltages of at least two different frequencies. a plurality of bandpass filters that output stop pulses based on the voltage of the
a counter provided for each of the band pulse filters that stops counting clock pulses in response to stop pulses of the plurality of band pass filters; and means for detecting a timing shift of the stop pulses based on the count value of the counter; The apparatus further includes a memory in which a correction value corresponding to the timing deviation is stored in advance.

[Effect]

When measuring the cursor position, the voltage induced in coil 2 is 2
The two stop pulses 18.
20 and supplied to counters 14.16 prepared for each bandpass filter 10.12. The difference between the tarok pulse count values of these counters 14.16 indicates the phase shift D of the stop pulses 18.20 output from the two bandpass filters 10.12, and the correction value corresponding to this shift is stored in the memory. The count value of the counter 14 or 16 is corrected using this correction value.

〔Example〕

The structure of the present invention will be described in detail below with reference to embodiments shown in the accompanying drawings.

In FIG. 1, 8 is a CPU (Central Processing Unit) with built-in ROM (Read Only Memory) and RAM (Random Access Memory).
The experimentally determined X-axis correction value corresponding to ΔX and the X-axis correction value corresponding to Δy shown in FIG. 4 are stored. The above ΔX is the stop pulse 2 of the bandpass filter 12.
0, the X coordinate value of the cursor obtained by the counter 16 is set to X2
, if the X coordinate value of the cursor obtained by the counter 14 by the stop pulse 18 of the bandpass filter 10 is xl, then the value is x, -X. The above Δy is calculated as follows: If the Y coordinate value of the cursor obtained by the counter 16 by the stop pulse of the band pass filter J2 is y, and the Y coordinate value of the cursor obtained by the counter 14 by the stop pulse of the band pass filter 1o is y□. , y2 3'l. As shown in FIG.
, and outputs stop pulses 18 and 20 to the counters 14 and 16, respectively, at the point where the fundamental wave 6 of the pick-up voltage (1) first becomes zero.

At this time, if the number of matrix conductors 4 in the cursor coil 2 is small, an error occurs in the output timing of the stop pulse 18.20 of the bandpass filter 1.0.12. Place the cursor on the conductors 4'' arranged in a 71-rick shape at predetermined intervals in the X-axis and Y-axis directions of the tablet, turn on the record switch, and the Glock generator 22 and shift register 24.26
The counter 14.16 starts counting clock pulses at the same time that pulsed currents with a constant time difference are supplied to the conductor 4 via the counter 14.16. When the cursor coil 2 catches the magnetic field generated in the conductor 4 by the pulse current and an induced voltage is generated in the coil 2, this induced voltage is transmitted to a band having passbands with different frequencies through the detection amplifier 28 and 30. A bandpass filter 10.12 is supplied to the pass filter 10.12.

A count stop pulse 18.20 is applied to the corresponding counter 14.16. Counter 14 at this time.
Assuming that the count value of 16 is X□+X2, Cf)08 calculates the difference ΔX between x2 and xl.

When a clock pulse is supplied to the shift register 26,
The counter 14.16 starts counting as soon as it is reset and continues counting until a stop pulse is supplied from the bandpass filter 10.12.

The count value of counter 14.16 at this time is 3'L.
, 3'Z, the CPU 8 calculates the difference Δy between y2 and yl. The CPU 8 extracts the y-axis and y-axis correction values stored in the ROM from the above ΔX and Δy, and uses the correction values to set the counter 1 on the tablet of the cursor.
4 or the count value of the counter 16 as a reference to calculate the correct X+y coordinate value.

〔effect〕

As described above, the present invention can reduce the number of matrix-like conductors without reducing reading accuracy, so it is possible to significantly reduce manufacturing man-hours, reduce material costs, and improve quality. There is an effect.

[Brief explanation of the drawing]

FIG. 1 is a block circuit diagram, and FIGS. 2 to 7 are explanatory diagrams. 2... Coil, 4... Conductor, 6... Fundamental wave, 8...
...CPU, 18.20...stop pulse. Patent Applicant: Muto Kogyo Co., Ltd. Representative Patent Attorney Aya Nishijima

Claims (2)

[Claims] (1) An induced voltage is generated in the cursor coil by a magnetic field signal from the tablet side where the matrix conductor is arranged, and this induced voltage stops the clock pulse counting operation of the counter to count the position of the cursor on the tablet. In the electromagnetic induction coordinate analyzer, a plurality of bandpass filters are connected to the coil and divide the coil-induced voltage into voltages of at least two different frequencies and output a stop pulse based on each voltage; a counter provided for each band-pass filter that stops counting clock pulses in response to stop pulses of a plurality of band-pass filters; a means for detecting a timing shift of the stop pulses based on a count value of the counter; A control device comprising: a memory in which a correction value corresponding to a timing shift is stored in advance. (2) An induced voltage is generated in the cursor coil by a magnetic field signal from the tablet side where the matrix conductor 4 is arranged, and this induced voltage generates a stop pulse to stop the clock pulse counting operation of the counter. In the electromagnetic induction coordinate analyzer, a correction value corresponding to the timing shift of the stop pulse between different frequencies of the induced voltage is registered in advance in the memory, and when measuring the position of the cursor, the induced voltage of the coil is Divide into a plurality of different frequency bands, generate stop pulses for each frequency band, control a counter with these stop pulses, and determine the timing of the stop pulse between different frequencies of the induced voltage in the coil from the count value of the counter. A control method comprising: calculating a deviation, and correcting the count value of the counter with the corresponding correction value based on the deviation.