JPH0372218A - Measuring apparatus of moving amount - Google Patents

Abstract

PURPOSE:To measure the pitch moving amount and a fraction value thereof by adjusting the amplifying ratio of a first and a second amplifying means so that the square average of a first and a second digital data be a set value. CONSTITUTION:A trigonometrical calculating means of a CPU 8 calculates the ratio of a first and a second digital data. The ratio is changed to a data Rd corresponding to an angle theta expressed by the correlation of the level of a first and a second electric signals by a reciprocal number converting means of the CPU 8. The amplifying ratio of a first and a second amplifying means 5x, 5y is adjusted so that the square average of the first and second digital data becomes a set value. Therefore, even if each level of the first and second electric signals generated by electric signal generators 1-4x, 1-4y is changed in the same direction, the ratio is practically not changed, thereby producing no change in the data Rd. Accordingly, the fraction value Rd can be measured correctly. It becomes correct to operate the pitch moving amount by a counting means of the CPU 8 based on the fraction value Rd. The pitch moving amount and fraction value thereof can be measured with high accuracy.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a command speed signal generator such as a linear encoder or a rotary encoder that generates one cycle of electrical signals for a predetermined small amount of linear motion or rotational motion. Regarding the movement amount measuring device used, in particular, the position of two sets is 90 degrees to each other in one period for the movement of a predetermined unit of linear motion, two rotations, etc. of the material to be measured for the movement amount.
Movement distance measurement using an electrical signal generator that generates shifted first and second electrical signals! Regarding A position.

[Conventional technology]

Conventionally, this type of measuring device includes a comparator that binarizes first and second electric signals and shapes them into first and second electric pulses, and a direction that detects the direction of movement from the first and second electric pulses. It has a detection means and an up/down counter that counts and amplifies the first electric pulse when the moving direction is positive or reverse, and counts down when the moving direction is the other direction. The count data of the counter represents the amount of movement.

For example, if the electric signal generator is one in which a light source and two sets of photosensors are installed between a moving slit plate and a fixed slit plate in which transparent slits are formed at a predetermined pitch,
The movement amount (count data) has one pitch of the transparent slit as the minimum unit, and generally the value of a fraction (less than one pitch) cannot be determined. However, during one pitch of movement, the first and second electrical signals each show a level change of one period, so the fractional movement amount is calculated based on the levels of these signals, and the fractional movement amount data is calculated. You can also get

[Problem to be solved by the invention]

When the level of the electrical signal generated by the electrical I generator changes, such as when the amount of light or light intensity of the light source changes, the calculation of the amount of movement of the fraction A11 changes accordingly, and the accuracy of measuring the fraction is low.

In addition, the above-mentioned up/down counter is omitted, a fractional value is calculated from the level of the electrical signal generated by the electrical signal generator, and when the fractional value increases to a value equivalent to one pitch amount, the pitch amount detection value is Update the number by 1 and change the fractional value to O.
If the fractional value decreases from O to ['L in the force direction, the pitch amount detection value is updated to l a smaller number, and the movement f11j to obtain the pitch amount detection value + fractional value is performed.The calculation is relatively long. It takes time and the moving speed is fast, and the tracking speed of the moving claw measurement value with respect to the actual moving amount is low.

The pitch amount is obtained from the count data of the counter by using two series of up/down counters and an arithmetic processing means that calculates a fractional value from the level of the electrical signal generated by the electrical signal generator. By calculating only fractional value data, the calculation processing for counting the pitch amount by the calculation processing means is omitted, and the speed at which the movement amount measurement value follows the actual movement amount increases. However, up/
It is impossible to perfectly match the timing at which the down counter counts up/down with the timing at which the arithmetic processing means calculates a fractional value of 0 due to electrical circuits and arithmetic processing. /In an extremely narrow range including the timing of downtime,
For example, when the arithmetic processing means calculates a fractional value O, the up/down counter is still counting up (or down).
or, conversely, when the up/down counter counts up (or down), the calculated value of the arithmetic processing means is a value different from the fractional value 0. The changes in the fractional values do not match, and this results in a measurement error of approximately one pitch. Although such an error occurs only within a very narrow range including the timing when the up/down counter moves from 1 to 1 up/down, it becomes a problem because it appears every time the up/down counter moves by one pitch.

SUMMARY OF THE INVENTION An object of the present invention is to provide a device that measures the amount of pitch movement and its fractional value with high accuracy.

[Means to solve the problem]

The measuring device of the present invention is coupled to an object to be measured for the amount of movement, and is capable of measuring one period for a predetermined unit of linear movement, one rotational movement, etc.
An electric signal generator (1 to 4xl'!l') that generates two sets of first and second electric signals whose positions are shifted by 90'' from each other.
a first electrical signal amplifying the first and second electrical signals, respectively;
and second amplification means (5x, 5y); signal (Lc) amplified by the first and second amplification means (5x, 5y).

A/D conversion means (7) for converting the level of Ls) into first and second digital data, respectively; first and second
The increase rate of the first and second amplification means (5x, 5y) is set to 1! so that the root mean square of the digital data becomes the set value.
13I sensing signal level adjustment means (8); trigonometric function value calculation means (8) for calculating the ratio of the first and second digital data; Inverse conversion means (8) for converting into data (Rd) corresponding to the angle (0) expressed by the correlation of the levels of the electric signals in movement 1; and the value corresponding to the predetermined angle (0°) (
0) Passage is detected and the predetermined angle corresponding value passes in one direction (
(clockwise), the pitch movement amount information (CS) is updated to a larger value equivalent to one pitch, and the pitch movement amount information (CS) is updated to a value larger than the value equivalent to one pitch, and
In this case, the count means (8) updates the value corresponding to one pitch to a smaller value; and, from the pitch movement amount information (CS) and the angle correspondence data (Rd), the pitch movement amount (CS) and the movement within one pitch u( movement amount information calculation means (8) for generating information (TR) including Rd); Note that symbols in parentheses indicate corresponding elements in the embodiments shown in the drawings and described later.

[Operation 1] The trigonometric function value calculation means (8) calculates the ratio of the first and second digital data, and the inverse conversion means (8) converts this ratio into
Since it is converted into data (Rd) corresponding to the angle (θ) expressed by the correlation between the levels of the first and second electrical signals,
The first signal generated by the electrical signal generator (l~4x, 4y)
Even if the levels of both the electric signal and the second electric signal change in the same direction, the ratio does not substantially change, and the data (Rd) does not change. Therefore, the measurement of the fractional value (Rd) becomes accurate. 1st
and when the level of the second electrical signal fluctuates greatly, A/
The resolution of D conversion increases the error in conversion to digital data, which also affects the calculation ratio.
In the present invention, the signal level adjustment means (8) adjusts the amplification factors of the first and second amplification means (5x, 5y) so that the root mean square of the first and second digital data becomes the set value. Therefore, fluctuations in errors in conversion to digital data due to resolution of A/D conversion are small, ratios are calculated with stable and high precision, and fractional values (IM) are accurately measured.

Since the measurement of the fractional value (Rd) is accurate, the calculation of the pitch movement amount based on the fractional value (Rd) by the counting means (8) is also accurate, and therefore the pitch movement amount and its fractional value are accurate. be measured.

[Means for Solving Problem 2] The measuring device of the present invention is connected to a movement measurement object, and measures one cycle of movement for a predetermined unit of linear movement, two rotational movement, etc.
Electric signal generators (1 to 4xr 4y) that generate two sets of first and second electric signals whose positions are shifted by 90 degrees;
Binarization means (6) that binarizes the first and second electrical signals into first and second pulse signals (A, B); moves from the first and second pulse signals (A, B) direction detection means (1) for generating a direction signal representing the direction of movement of the object to be measured
0); When the direction signal is in one direction (clockwise), one of the first and second pulse signals (A, B) (A) is counted up, and when the direction signal is in the other direction (counterclockwise), it is counted down. an up/down counter (11) that amplifies the first and second electrical signals; first and second amplification means (5x, 5y) that amplify the first and second electrical signals, respectively; A/D that converts the level of the amplified signal into first and second digital data, respectively.
Conversion means (7); Trigonometric function value calculation means (8) that calculates the ratio of first and second digital data; Trigonometric function value calculation means (8) converts the ratio calculated by the trigonometric function value calculation means (8) into data (R
Inverse conversion means (8) for converting into d); angle-corresponding data (R
From the transition in d), the direction of movement of the object to be measured and the passage of the corresponding value (0) at a predetermined angle (0°) are detected, and when the passage of the corresponding value at the predetermined angle is in one direction (clockwise), the pitch movement is detected. Counting means (8) for updating the amount information (CS) to a value larger than one pitch equivalent, and updating it to a smaller value equivalent to one pitch when in the other direction (counterclockwise);
r) from pitch movement amount information (CS) and angle correspondence data (Rd).

Pitch movement m <cs> and l pitch movement amount (Rd
), and generates information (TTt) including the nearest area (Ar,”
Outside of 1, information (TR) including pitch movement i (Rp) and movement amount within 1 pitch (Rd) is generated from the count data (Rp) of the up/down counter (11) and angle corresponding data (Rd). do. Transfer IJJ amount information calculation means (
8);

[Operation 2] In a wide range outside the immediate area (Ar) including the timing when the up/down counter (11) counts up/down, the movement amount information calculation means (8) Information (CTR) including the pitch movement amount (Rp) and l-pitch movement amount (Rd) is generated from the count data (Rp) and angle-corresponding data (Rd). Since there is no need to perform pitch movement amount calculation processing such as determining whether to count up or down the pitch movement amount, and because the up/down counter (1) counts quickly, the measured value of the movement amount relative to the actual movement amount High tracking accuracy. In the immediate area (Ar) including the timing at which the up/down counter (11) counts up/down, the counting means (8) calculates the value based on the transition of the angle-corresponding data (Rd).
Detects the direction of movement of the object to be measured and passage of a value (0) corresponding to a predetermined angle (0°), and when the passage of the value corresponding to a predetermined angle is in one direction (clockwise), the pitch movement amount information (CS) is detected. The 1-pitch equivalent value is updated to a larger value, and in the other direction (counterclockwise), the 1-pitch equivalent value is updated to a smaller value, and the movement amount information calculation means (8) calculates the pitch movement amount information (CS).
From the data (Rd) corresponding to the angle and angle, the pitch movement amount (CS
) and information (TR) including the amount of movement within one pitch (Rd)
Therefore, the switching of the pitch movement amount information (CS) and the change in the one-pitch movement amount (Rd) are matched (linked), and a measurement error of about 1 pisoti is not generated between the two.

The above-mentioned pitch movement amount information (CS) of the counting means (8)
It takes a relatively long time to calculate, but since the area (Ar) in which this is performed is extremely narrow, 1llII
The followability of the time series average of the I constant device does not deteriorate particularly greatly.

In a preferred embodiment of the present invention, the trigonometric function value calculation means includes:
The first and second digital data are compared and the direction (angle) of their combined vector is No, O: O°
More than 45 degrees.

No. 1: 45° or more and less than 90°.

No. 2: 90° or more and less than 135″′.

No. 3: 1.35'' or more and less than 1806.

N0142 180° or more and less than 225°.

No. 5: 225° or more and less than 270°.

No. 6: 270° or more and less than 3156°.

No, 7: 315° or more 360' not i1't
A.

If any of the above is detected, and if No, o, 3.4 or 7 is detected, the ratio of the absolute values of the first and second digital data corresponding to the tangent value is calculated, and the result is No, 1.2°5. or 6, the first value corresponding to the reciprocal of the tangent value is detected.
and the ratio of the absolute values of the second digital data is calculated.

Electrical signals (Ls=Sin O+Vsm, Lc=Cos e
+Vsm) indicates the level (vertical axis) shown in FIG. 2a with respect to the radical P HM position Vsm. One cycle of this level is 1
It's pitch. If the electrical signal generator (1 to 4x, 4y) and the amplification means (5x, 5y) are ideally designed, or by calibration by adjusting the amplification factor of the amplification means (6y, 6x), the results shown in Fig. 2a can be obtained. As shown, the amplified first and second electrical signals (Ls = Sinθ+Vsm, Lc
= Cos O + Vsm) have the same extreme values, making it an ideal Si
When the n function and the Cos function appear, as shown in FIG.
It can be determined which of the quadrants N010 to N07 (FIG. 3) in which 0° is divided into eight equal parts is located.

Assuming that the quadrants are defined in this way and it is determined in which quadrant θ is located, the fluctuation level of the electrical signal (Ls = Sin
Focusing on the absolute value of θ, Lc = Cos θ), it is shown in FIG. 2b.

No, in the O quadrant, Tan OL= Sinθ / CosθL
s / Lc, so calculate ILs l / l Lc l, take this as the value of Tan Ot, calculate θ by inverse transformation (arc tan diene 1 ~), and set this as the detected angle 0. obtain.

No. 1 quadrant, as shown by the arrow in Figure 2b, 90
If you look in the direction of decreasing angle with ° as the base point, j Ls l in the No, 0 quadrant and 11. The angle in the decreasing direction can be calculated by replacing c and l. That is, Co50ct, /
Calculate 5jn (Jet=Lc/Ls, assume this is the value of Tan Ocj, calculate oct by inverse transformation (arctangent),
Then, the angle θ can be determined as 0=90°−0ct.

In the N002 quadrant, 90
When looking in the direction of increasing angle with ° as the base point, the angle in the increasing direction can be calculated by replacing l Ls l and 1Lc1 in the No and 0 quadrants. That is, Tan fJ cj=Co50ct/
Sir+Oct.

By calculating Lc/Ls and assuming that this is the value of TanθcL, oct is calculated by inverse transformation (arctangent), and the angle θ can be obtained as θ=90°+Oct.

No. 18 in quadrant 3, as shown by the arrow in Figure 2b.
When looking in the direction of decreasing angle from 0° as the base point, the angle in the decreasing direction can be calculated in the same manner as in the case of the No. 0 quadrant. That is, Tan OL= Sin Oj / Cos O
t.

” By calculating Ls/Lc and assuming that this is the value of TanθL, θt is calculated by inverse transformation (arctangent), and the angle θ can be determined as 0=180°−θt.

No. 18 in quadrant 4, as shown by the arrow in Figure 2b.
When looking in the direction of increasing angle from 0° as the base point, the angle in the increasing direction can be calculated in the same manner as in the case of the N000 quadrant. That is, Tanθ = 1sinf7t, l/1cosOtL
Calculate s l / l Lc, assume this is the value of Tan Ot, and calculate ohi) by inverse transformation (arctangent).

Then, the angle θ can be determined as θ=180°+OL.

No. In the 5th quadrant, as shown by the arrow in Figure 2b, 27
If you look in the direction of decreasing angle with 0° as the base point, l Ls l and l I-c l in the No and ○ quadrants are swapped,
The angle in the decreasing direction can be calculated. That is, Tan Ocj= Cos Oct/
5ift Oct=Lc/Ls is calculated, and this is assumed to be the value of Tan Oat, and oCt is calculated by inverse transformation (arctangent).

Therefore, the angle θ can be found as θ=270°−0ct.

No. In the 6th quadrant, as shown by the arrow in Figure 2b, 27
When looking in the direction of increasing angle with 0' as the base point, l Ls l and l Lc l in the No, 0 quadrant are swapped,
The angle in the increasing direction can be calculated. That is, Tan0cj=Co50ct, /Sir
+Oc = Lc / Ls is calculated, and this is assumed to be the value of Tan Oct, and by inverse transformation (arc tangent), oct is calculated, and the angle θ is found as 0 = 210° + Oct. can.

No. In the 7th quadrant, as shown by the arrow in Figure 2b, 36
When looking in the direction of decreasing angle from 0° as the base point, the angle in the decreasing direction can be calculated in the same manner as in the case of the No. 0 quadrant. That is, Tan Ot= Sin Ot / Cos O
t.

Calculate = l-s / l-c and assume this is the value of Tan Ot, then j1
By calculating OL by 'fL conversion (arctangent), it is possible to find the angle 0.

By calculating in this way, θhi, (lcj is 0 to
The range is 45°, and the data needed to inversely calculate the angle from the trigonometric function value (tangent) is only needed for one quadrant (0-45°), which minimizes the amount of data, so the angular resolution can be improved accordingly. By increasing the angle θ, the angle θ can be calculated with high resolution. In a preferred embodiment described below, the angle O (inner pitch fraction) is expressed in units obtained by dividing one quadrant (0 to 45 degrees: 178 range of one pitch) into 1024.

Other objects and features of the invention will become apparent from the following description of an embodiment with reference to one drawing.

〔Example〕

FIG. 1 shows an embodiment of the present invention. Electric signal generator
Light source 8. A movable slit plate that is mechanically coupled to the object to be measured and moves reciprocally in the direction of the arrow in conjunction with the reciprocating linear motion, forward and reverse rotational movement of the object to be measured. It is composed of a fixed slit plate 2 and first and second photosensors 4y and 4x. In the movable slit plate 1 and the fixed slit plate 2, transparent windows having substantially the same pitch are formed at a predetermined pitch in the moving direction indicated by the arrow. Photo sensor 4y, 4x
receives the light that has passed through the translucent windows of slit plates 1 and 2, but a sine wave (or cosine wave) of one period is generated by one of the photosensors for one pitch of movement of movable slit plate 1. Both photosensors 4y and 4x are arranged such that the other photosensor generates a cosine wave (sine wave) electric signal with a phase shift of 90' with respect to the electric signal of
The relative position in the direction of the arrow is set.

The electrical signals generated by the photosensors 4y and 4x are as follows.

The signals are amplified by variable gain amplifiers 5y and 5x, respectively, and provided to a comparator 6 and an A/D converter 7.

The comparator 6 converts the amplified electric signal to its reference potential Vsm
is binarized to generate pulse signals A and B, which are applied to the direction detector 1o. Note that the comparator 6 has a hysteresis characteristic, and more precisely, the reference potential Vs
Binarization is performed at a potential slightly different from m.

Based on the level changes of pulse signals A and B, the direction detector 10 detects that signal A is high when signal a B is high level H.
When the low level L falls from the low level, the movable slit plate 1 becomes H, which indicates that the movable slit plate 1 is moving in the backward direction.
A direction signal (L) indicating that the is moving in the forward direction (
Q output of the flip-flop) is connected to the up/down instruction signal input terminal (UP/DOW) of up/down counter 1.
N). The signal A is inverted by the inverter of the direction detector IO and is applied to the count pulse input terminal (CK) of the up/down counter 1.

When the direction signal is L (forward movement), the amplifier/down counter 1 responds to the rise of the signal A from L to H (the fall of the inverted signal from I to L). When the cow flaps and the direction signal is H (return movement), a countdown of 1 is performed in response to the fall of the signal %A from H to L. Count data of the counter 1 is given to a microprocessor (hereinafter referred to as CPU) 8. A reset signal (L indicates reset) is given to the clear signal input terminal (CLrl) of the counter 1 and the CPU 8, and when the reset signal is L, the up/down counter 1 clears the count data to indicate ○. After the reset signal returns to H, the count up/down operation is performed.

Since the comparator 6 has hysteresis characteristics,
Electrical signal Ls=Sin generated by variable gain amplifier 5y
When the variation Sin O of θ+Vsm is 0, the signal A rises from L to H (falls from H to L), and the counter 11 should count up (down) at that point.
This rise (fall) of the signal A deviates from the timing of Sinθ=0 within the extremely narrow region Ar (-Ld<Sin O<Ld) shown in FIG. 2a, so the count-up of the counter 11 /Down timing is Si
It does not exactly match r+0=O.

The A/D converter 7 is a variable gain amplifier 5y.

Electrical signal Ls=Sin D +Vsm generated by 5X,
Since Lc=Cosθ+Vsn+ is converted into digital data with reference to the reference potential Vsm, the converted data of the converter 7 shows Ls=Sin O and Lc=Cos O.

The CPU 8 instructs the A/D converter 7 to digitally convert the signals Ls and Lc at the required timing.
=Sinθ and Lc=Cosθ digital data are obtained.

The variable gain amplifiers 5y and 5x have an output signal level (variable potential from the reference potential Vsm) with respect to an input signal level (variable potential from the reference potential Vsm).
Change j from base 1# potential Vsm! llll potential) (hereinafter simply referred to as gain), and once the CPU 8 instructs to increase (or decrease), the gain is amplified by the minimum step (down).

A display unit 1-9 is connected to the CPU 8, which includes a 3-digit character display for displaying the light emission intensity of the light source 3 and an 8-digit character display for displaying the amount of movement.

Also connected to the CPU 8 is a key switch HS that stops the display value from changing when reading the display.

In addition, key switches and the like are connected to the CPU 8 for calibrating display values and adjusting the reference gain, upper and lower limit values of the variable gain amplifier, etc.

Their illustration is omitted.

In this embodiment, as shown in FIG.
Ls=Sj-r+O during the movement of the transparent window by ■pitch
and Lc=CosO synthetic Peltor angle 0 to 360° (
In other words, calculate the angle θ (pitch fractional value) in the range of ■pitch) as a decimal value of 0 to 8192, and convert these values (0 to 8192) into an angle value (pitch fractional value) of 0 to 360°. After conversion, a 4-digit fraction (below the decimal point) and a 4-digit pitch number (above the decimal point) are displayed.

FIG. 5 shows the movement amount measurement operation of the CPU 8.

When the power is turned on, the CPU 8 clears its internal registers, counters, timers, etc., and gives data (display clear) to display all digits O to the 1 display unit 9 (SIN
). Next, give a reset signal to the variable gain amplifier 5y+5X, and then give the reference gain data Gm (AIN)
. The variable gain amplifiers 5y and 5x set the gain to the base value (lowest value) in response to the reset signal, and then increase the gain by one minimum unit (step) when receiving the reference gain data Gm. The number of times the gain has been changed is counted up, and when the count value reaches Gm, the gain change is stopped.

After that, when the key switch H8 is open, the CPU 8 reads "
The gain setting J (AGA) of the amplifiers 5x and 5y and the measurement J (MDD) of the amount of movement are repeated alternately. When a reset signal (=L) arrives from the outside, the up/down counter 11 is activated in response. At the same time as clearing itself (count f = 0), the CPU 8 sends a reset signal (
=L) in response.

Write the fractional value Rd calculated and held at that time to the initial value register (internal register) Rdj (3°4), clear the display data TR in the display value register TR to O, and write this on the display 9. Display (4..5).

"In amplifier 5 gain setting J (to AG), Ls = 5
Digitally convert and read 1nO and Lc=CO8O, sum of their squares (square of polar coordinate radius) Rds'lJ
<Adjust the gain of the amplifier 5 so that it falls within the setting range (Rss-A<Rds<Rss+B), calculate the emission intensity=gain Display on spray.

“In the measurement of movement amount J (MDD), Ls=Sin0
and Lc=CosO are digitally converted and read, and their correlation is the fisheye number of the 8 equal divisions shown in FIG.

Determine which of 0 to 7 it belongs to, calculate the angle O based on the determination result, convert the calculated angle 0 to the numerical value Rdal under the decimal point color, and use this to determine the contents of the initial value register C3i. The value obtained by the subtraction is displayed on a four-digit character display for displaying fractions of the display unit 9. In addition, the fractional value Rdal is within the predetermined range A shown in FIGS. 2a and 3.
It is determined whether or not it is within r, and if it is outside the range, the count value of the counter 11 is displayed on the 4-digit character display for displaying an integer value (pitch amount) of the display unit 9.

When it is within the range Ar, the transition of the fractional value Rdal is detected, and when it crosses 0 in the forward direction, the contents of the pitch count register C3 are updated to a value larger by 1, and when it crosses in the backward direction, the contents of the register C3 are updated. The data C3 of the register C3 is displayed on the 4-digit character display for displaying integer values of the display unit 9.

The gain setting J (AGA) of the amplifiers 5x and 5y and the movement measurement J (MDD) are repeated alternately. When the measured value changes, the display on the display unit 9 changes and the display characters flicker. Check the display accurately. When doing so, the operator closes the key switch HS.

While H3 is closed, the CPU 8 outputs “Amplifier 5x.

5y gain setting J (AGA) and "measurement of movement amount"
(MDD) are both stopped and waiting for H3 to open, the display unit 9 continues to display the measured value just before H5 was closed, and the displayed value does not change. When H3 returns to open, the CPU 8 sets the gain setting J (AGA) of amplifiers 5x and 5y and the measurement J (MDD) of the amount of movement.
Repeat alternately.

Figure 6a shows "gain settings for amplifiers 5x and 5y" (AG
The contents of A) are shown. "Amplifier 5x, 5y gain setting J
When proceeding to (AGA), the CPU 8 digitally converts Ls=SinO and Lc:Cosθ and reads them (1, 2).
, the sum of their squares Rcls is calculated (3), and this is the setting range (Rss - A < Rds < Rss + B
) (4.7).

If it is outside the lower setting range, check whether the sum of the gain G currently set for amplifier 5 plus 1 is greater than or equal to the gain upper limit value Gt (5), and if it is less than the upper limit value Gt. If so, the amplifier 5 is instructed to be a 1-step amplifier, the contents of the gain register (internal register) G are updated to the sum G+1, which is the value at that time plus 1 (6), and Ls=Sinθ
and L c = Cos O is digitally converted and read (1, 2). In this way, the gain G is increased sequentially. When the gain exceeds the upper limit value Gi, the increase in gain is stopped, and the root mean square of the digital data of Ls=SinO and r-c=coso at that time is multiplied by the gain G at that time, and the result is obtained. Display unit 9 for value Mf
, and updates and displays it on the character display for displaying the luminescence intensity (10.11), sets the gain to the upper limit value Gj (1, 2), and starts the main routine (5th
Return to Figure) (proceed to MDD).

The sum Rds is within the setting range (Rss - A < Rds < R
ss + B), it is checked whether the value obtained by subtracting 1 from the gain G currently set for the amplifier 5 is less than the gain lower limit value Gb (13), and it is determined that the lower limit value Gb is If it exceeds the current value, it instructs the amplifier 5 to step down by one step, updates the contents of the gain register G to the remaining value G - 1, which is obtained by subtracting 1 from the value at that time (14), and also sets Ls=S.
ir+O and Lc=CosO are digitally converted and read (1, 2). In this way, the gain G is successively lowered. When the gain becomes below the lower limit value Gb, the gain reduction is stopped and Ls=SjnO and L
The root mean square of the digital data of c=CosO is multiplied by the gain G at that time, the obtained value Mf is given to the display unit 9, and it is updated and displayed on the character display for displaying the light emission intensity (15, 1 .6). Then, the gain is set to the lower limit value Gb (17), and the process returns to the main routine (FIG. 5) (proceeds to 14DD).

Figure 6b shows the contents of ``Measurement of movement amount J (Ml)D). When proceeding to ``Measurement of movement amount J (MDD)'', the CPU
8 digitally converts and reads Ls=SinO and Lc=CosO (21, 22), and determines which of quadrants No. 30 to 7 these data (direction of the composite vector of) belongs to by dividing 360° into 8 equal parts. and determines data Dabc representing the determined quadrant N011 (23
). Quadrant no.

FIG. 4 shows the relationship between the polarity of Ls=SinO and Lc=CosO, the magnitude relationship of Ls=Sir+0 and Lc=CosB, and the quadrant data D abc determined by paying attention to these.

That is, in the determination (23) of quadrant No.

No, 0: When Ls, Lc≧reference value (0), and LSI<ILc, D abc is changed to data indicating O in decimal (00
0), No, 1: Ls, Lc≧Reference value (0), and when Ls≧Lc, Dabc is set to data indicating 1 in decimal (001
), No. 2: Ls≧reference value (0), Lc<reference value (0).
) and when Ls ≧ Lc, Dabc is converted into data indicating decimal number 2 (010
), No.3: Ls≧reference value (0), Lc<reference value (0).
) and when Ls < Lc, D abc is changed to data indicating decimal number 3 (01
1), No, 4: Ls, Lc<reference value (0), and Lsl<1Lcl, then Dabc is converted to data indicating O in decimal (1,0
0), No, 5: Ls, Lc<reference value (0), and Lsl≧1Lcl, then D abc is set to data indicating 5 in decimal number (10
1), No, 6: Ls<standard value (0), Lc≧standard value (0
) and if Ls ≧ Lc, Dabc is converted into data indicating decimal number 6 (1, 1
0), No, 7: Ls<standard value (0), Lc≧standard value (
0) and Ls < Lc, Dabc is converted to data indicating decimal number 7 (111
).

When quadrant data D abc is determined, this data D ab
When Dabc is 0°3.4 or 7, corresponding to the content of c (detected quadrant).

Calculate Tan011 Ls/Lc,
When Dabc is 1.2.5 or 6, calculate Tan0c = Lc / Ls (25
: 25o~25□).

Next, the CPU 8 calculates the calculated Tan011. Or Tan
Oct.

is inversely transformed into an angle value OL or Oct (26). The details will be described later with reference to FIG. 6c. Angle OL or o
ct is within the range of 0° or more and 45° or less. These angles are 2-byte data and are expressed in decimal numbers from 0 to 1024.

Next, the CPU 8 converts the obtained angle value into Ls=Sin O=0
Convert to an angle value (θ) based on the angle (0) of (2
7: 27o~277). The converted angle value (o) is
It is 2-byte data and is expressed as a decimal number from 0 to 8191.

The CPU 8 then converts the converted angle value (0), that is, the fractional value of the pitch, to a value below the decimal point and writes this to the current value register Rda1 that stores the currently calculated fractional value (8). .

Next, based on the previously read polarity of Lc=CosO and absolute value of Ls=SinO, the CPU 8 determines the timing (θ=0°) at which the direction (f) of their combined vector is to perform pitch count up/down. (82, 83), and if it is outside the area, the pitch movement amount register Rp is set to the counter 1. The count data is written (84), and the currently calculated fractional value Rdal is written in the fractional value register C3d (85).

Then, Rp+Rd-Rdi is calculated and written in the movement amount register TR (86), and the value indicated by the data in the movement amount register TR is updated and displayed on the character display 9. This display value is based on the pitch movement amount calculated by the counter 11 and the movement amount fraction value calculated by the CPU 8 after rising from L, which instructs reset, to H, which instructs measurement. Calculated based on The amount of movement of the movable slit plate 1 (integer 1 corresponds to the slit pitch) is shown.

When the direction (O) of the composite vector of Lc=CosO and Ls=Sir+O is within the set small area Ar before and after the pitch count up/down timing (0=0°), the CPU 8 uses the previously calculated fractional value. Rda2 and the fractional value Rdal calculated this time are the 180° corresponding value Rda (
4096) is greater than (88,
89), whether it crossed the 0° corresponding value Rda(0),
If it crosses, the direction (clockwise or counterclockwise in Fig. 3) is detected (88, 89; 88, 90), and if it crosses clockwise (Fig. 3), the contents of pitch movement count register C3 are detected. Please update 1 to a larger number (91),
When it crosses in the counterclockwise direction, the contents of the pitch movement amount count register C5 are updated to a number smaller by 1 (92). When there is no cross-cutting, the register C3 is not incremented or decremented.

Next, the CPU 8 stores the data in the current value register Rda1 (the fractional value data calculated this time) in the previous value register Rda.
2, and writes the data of the pitch movement amount count register C3 to the pitch movement amount register Rp (94). Then, the fraction value Rdal calculated this time is stored in the fraction value register C3.
is written (85). Then calculate Rp+RdRdi and write this to the movement amount register TR;7. %(86),
The value indicated by the data in the movement amount register TR is updated and displayed on the character display 9. This display value is the pitch movement amount and fractional value shift calculated by the CPU 8 after the reset signal rises from L, which instructs reset, to H, which instructs measurement. I? I] indicates the amount.

As mentioned above, the hardware up/down counter 1
] is taken as Ls=Sinf) and c=CosO in the small area Ar including the up/down timing from Karan 1.
When there is a direction O (fractional value of the amount of movement) of the resultant vector, the CPU 8 calculates the current fractional value Rda calculated by itself.
Determine the moving direction of the movable slit plate 1 from l and the previous fractional value Rda2, and determine whether it has crossed the position (fractional value 0) where the pitch movement amount is 1/up/down.
When the fractional value O is crossed in the forward direction (clockwise in Figure 3), the pitch movement amount count register C3 is incremented by 1,
When the fractional value 0 is crossed in the backward direction (counterclockwise), the pitch movement amount count register C3 is counted down by 1, and based on C3 and the fractional value R, da1, the movement 1TR (= pitch movement amount C5 + fractional value Rda1 - initial value of the fractional value) The value Rdj) is calculated and displayed on the display 9.

Outside the small area Ar, neither the hardware up/down counter 11 nor the pitch movement amount count register C3 counts up or down, so their data completely match. Here, it is not necessary to determine whether or not the pitch movement amount count register C5 needs to be amplified or down, so it is based on the count data Rp (pitch shift ffJJ amount) of the up/down counter 11 and the fractional value Rdal calculated by the CPU 8. The amount of movement T R (= Rp+
Rdal - Rdi) is calculated and displayed on the display 9.

With reference to Figure 6c, Tan O or Tan Oct
The contents of the inverse conversion (26) of ; into the angle value θL or Oct will be explained. The internal memory of the CPU 8 stores angles (AO:
0(0°)-1024(45°)] tangent value TTn(A
e)=R(0) to R(1024) are stored as data for angle determination. i.e. 0-45
A tangent function inverse conversion table in the range of ° (0 to 1o24) is prepared.

When the CPU 8 proceeds to the inverse transformation (26), it first calculates Av=Ta.
nθhi or Tan Oct: in the angular range (0-102
4), the tangent value R(512) of the intermediate value 512 is 3.
1), if Av<R(51,2), then Av is compared with the tangent value R(256) of the angle 256 (32). In this way, for example, when Av='R(4), that is, Av is the tangent value of the IO semi-large display angle 4, steps 31-32-33-34-35-36-37-38-
42-43, it is determined that the angle AO of the tangent value Av is angle 4 (704). As a result, the angle is calculated as 0 through 10 comparison and determination steps.

As described above, the count up/down of the pitch movement amount is performed only in the small area Ar, and the count up/down is not performed in the wide area outside the areas A and r. Furthermore, since the CPU 8 counts up/down the amount of pitch movement when there is a change of one pitch within the information area Ar, the hardware counter 11 may be omitted depending on the purpose of the measuring device.

FIG. 7a shows the configuration of a second embodiment of the present invention.

In this embodiment, the hardware counter 11 is omitted,
In addition, the comparator 6 and direction detector 10 are also omitted. The variable gain amplifier 5y receives the amplified light reception signal Ls=Sin
O+Vsmy and its Jj;S potential (intermediate value of the fluctuation range of the received light signal) Vsmy are
The variable gain amplifier 5X receives the amplified light reception signal L
c = Cos θ + Vsmx and its base potential (intermediate value of the fluctuation range of the received light signal) Vsmx are converted to the A/D converter 7.
is applied to the second analog/digital conversion input terminal and reference potential input terminal.

The A/D converter 7 has base F m positions Vsmy, Vs
The levels of signal potentials Ls and Lc with respect to mx are converted into digital pigtails.

The CPU 8 has a built-in movement amount detection program roughly similar to that of the first embodiment (FIG. 1) described above. This second
Only the portions of the movement amount detection program of the embodiment that are different from those of the first embodiment are shown in FIG. 7b. This corresponds to subroutine 81 to step 94 in FIG. 6b. The other parts are the same as those of the first embodiment. Referring to FIG. 7b, in this second embodiment, CP
When U8 determines that it is outside the small area Ar, it writes the data in the pitch movement amount register C8 to the register RP (84). That is, since there is no up/down counter 11, the data in the pitch movement amount register C8 is written as is into the register Rp. Since the data of the pitch movement amount register C3 is written to the register Rρ even when it is within the range of the small area Ar, in this second embodiment, the pitch movement amount ( integer value).

The value counted by the CPU 8 is used. However, the count up/down of the pitch movement amount (integer value) is limited to a small range A.
Since it is only necessary to perform the count up/down within r, the determination of whether or not count up/down is necessary (88 to 90) is performed only within the small range Ar, and is not performed in the range outside Ar.

〔Effect of the invention〕

As described above, in one aspect of the present invention, the trigonometric function value calculation means (8) calculates the ratio of the first and second digital data, and the inverse conversion means (8) converts this ratio into the first and second digital data. The electric signal generator (
Even if the levels of the first and second electrical signals (1 to 4x, 4y) generated change in the same direction, the ratio does not substantially change, and the data (Rd) does not change. Therefore, the fractional value (
Rd) becomes accurate.

When the level fluctuations of the first and second electrical signals are large,
The resolution of A/D conversion increases the error in conversion to digital data, which also affects the calculation ratio, but in the present invention, the solid bell tone IJ':i means (8) is The first and second amplification means (5x,
Since the amplification factor of 5y) is adjusted, the fluctuation of the error in conversion to digital data due to the resolution of A/D conversion is small, the ratio is calculated with stable and high accuracy, and the fractional value (Rd)
measurements are made accurately.

Since the measurement of the fractional value (Rd) is accurate, the calculation of the pitch movement amount based on the fractional value (Rd) by the counting means (8) is also accurate, and therefore the pitch movement amount and its fractional value are accurate. be measured.

Further, in another aspect of the present invention, in a wide range outside the immediate area (Ar) including the timing when the up/down counter (11) counts up/down, the movement amount information calculation means (8) /down counter (1
1) count data (Rp) and angle corresponding data (R
From d), information (TR) including the pitch movement amount (Rp) and the movement amount within one pitch (Rd) is generated.
Since there is no need to calculate the amount of pitch movement, such as determining whether hair bumps/downs are necessary, the up/down counter (11
) is high, so the tracking accuracy of the measured value of the amount of movement relative to the actual amount of movement is high. In the immediate area (Ar) including the timing at which the up/down counter (11) counts up/down, the number 1-means (8
) is the amount of movement Hi from the transition of angle-corresponding data (Rd)
The direction of movement of the fixed object and the corresponding value of the predetermined angle (0°) (
0) Passage is detected and the predetermined angle corresponding value passes in one direction (
(clockwise), pitch shift! I! I]i information (C5)
is updated to a larger value equivalent to 1 pitch, and in the other direction (counterclockwise) to a smaller value equivalent to 1 pitch,
The movement amount information calculation means (8) calculates pitch movement amount information (CS
) and angle corresponding data (Rd), the pitch movement amount (C
5) and information (Ti
t), the switching of the pitch movement amount information (C5) and the change in the movement amount within one pitch (Rd) are matched (linked), and a measurement error of approximately one pitch is not generated between the two. It takes a relatively long time to calculate the above-mentioned pitch movement amount information (CS) by the counting means (8), but since the area (Ar) in which this is performed is extremely narrow, the time series of the measuring device The average followability does not drop significantly.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a first embodiment of the present invention. FIG. 2a is a time chart showing the levels of signals output by the variable gain amplifiers 5y and 5X shown in FIG. 1. FIG. 2b is a time chart showing the absolute value level of only the variation of the signals output by the amplifiers 5y and 5X shown in FIG. FIG. 3 is a plan view showing the direction 0 of the composite vector of fluctuations in the output signals Ls and Lo of the variable gain amplifiers 5y and 5X, and the quadrant divisions obtained by dividing the entire range O to 360° in the direction O into 8 equal parts. It is. FIG. 4 shows the correlation between the quadrant to which the direction θ belongs and the signal levels Ls and Lc of the amplifiers 5y and 5x shown in FIG. 1, as well as the data generated by the CPU 8 shown in FIG. 1 in each quadrant. FIG. 5, 6a, 6b, and 6c are flowcharts showing the contents of the arithmetic processing of the CPU 8 shown in FIG. 1. FIG. 7a is a block diagram showing a second embodiment of the invention. FIG. 7b is a flowchart 1- showing the content of the arithmetic processing of the CPU 8 shown in FIG. 7a, and the CPU 8 shown in FIG.
Only the parts that are different from the calculation process are shown. 1: Movable slit plate 2: Fixed slit plate 3
: Light source 4x, 6y: Photo sensor (1 to 4x, 4y: electrical signal generator) 5x, 5y: Variable gain amplifier (first and second amplification means) 6: Comparator (binarization means) 7: A /D
Converter (A/D conversion means) 8: Microprocessor (signal level adjustment means, trigonometric function value calculation means, inverse conversion means, counting means, movement amount information calculation means) 9: Display unit 10 Two-direction detector (direction detection means) )
11 Near Tsubu/Down Katana Counter (Up/Down Counter) H5: Key Switch

Claims (3)

[Claims] (1) Two sets of first and second electrical signals whose positions are shifted by 90 degrees from each other are connected to the object to be measured and have one cycle for a predetermined unit of linear movement, rotational movement, etc. an electrical signal generator that generates electrical signals; first and second amplifying means that amplify the first and second electrical signals, respectively; Converting to digital data A/
D conversion means; signal level adjustment means for adjusting the amplification factors of the first and second amplification means so that the root mean square of the first and second digital data becomes a set value; the first and second digital data Trigonometric function value calculation means for calculating the ratio; Inverse conversion means for converting the ratio calculated by the trigonometric function value calculation means into angle correspondence data represented by the correlation between the levels of the first and second electrical signals; Angle correspondence From the data transition, detect the direction of movement of the object to be measured and the passing of the predetermined angle corresponding value, and when the predetermined angle corresponding value passes in one direction,
Update the pitch movement amount information to a value larger than the value equivalent to 1 pitch,
When in the other direction, a counting means updates the value equivalent to one pitch to a smaller value; and movement amount information that generates information including the pitch movement amount and the movement amount within one pitch from the data corresponding to the pitch movement amount information and the angle. A displacement measuring device comprising: calculation means; (2) Two sets of first and second electric signals whose positions are shifted by 90 degrees from each other are connected to the object to be measured and have one cycle for a predetermined unit of linear movement, rotational movement, etc. An electric signal generator that generates; a binarization means that binarizes the first and second electric signals into first and second pulse signals; direction detecting means for generating a direction signal representing a direction; an up/down counter that counts up one of the first and second pulse signals when the direction signal is in one direction and counts down when the direction signal is in the other direction; first and second amplification means for amplifying the first and second electrical signals;
D conversion means; trigonometric function value calculation means for calculating the ratio of the first and second digital data; inverse conversion means for converting the ratio calculated by the trigonometric function value calculation means into angle-corresponding data; In the immediate area including the timing of counting up/down, the direction of movement of the object to be measured and the passing of the predetermined angle corresponding value are detected from the transition of the data corresponding to the angle, and the passage of the predetermined angle corresponding value is detected in one direction. a counting means for updating the pitch movement amount information to a value larger than one pitch equivalent when the direction is reached, and updating the pitch movement amount information to a smaller value equivalent to one pitch when in the other direction; and, within the immediate area, the pitch movement amount information and the angle Information including the amount of pitch movement and the amount of movement within one pitch is generated from the corresponding data, and outside the immediate area, the amount of pitch movement and the amount of movement within one pitch is generated from the count data of the up/down counter and the data corresponding to the angle. A movement amount measuring device comprising: movement amount information calculation means for generating information including; (3) The trigonometric function value calculation means compares the first and second digital data and determines whether the angle represented by them is No. 0: 0° or more and less than 45°, No. 1: 45° or more and less than 90°, No. 2: 90° or more and less than 135°, No. 3: 135° or more and less than 180°, No. 4: 180° or more and less than 225°, No. 5: 225° or more and less than 270°, No. 6: 270° or more and less than 315°, No. 7: Detects either 315° or more and less than 360°, and No. When No. 0, 3, 4, or 7 is detected, the ratio of the absolute values of the first and second digital data corresponding to the tangent value is calculated. 1, 2, 5, or 6, the ratio of the absolute values of the first and second digital data corresponding to the reciprocal of the tangent value is calculated. ) The displacement measurement device described in section 2.