JPH0763578A - Scale device - Google Patents

Abstract

PURPOSE:To provide a scale device simple in circuit constitution with the absolute value preset only by the pulse number in a state of small relative moving distance between a first and a second detecting heads and a first and a second scales from the initial positions of the first and second detecting heads. CONSTITUTION:A first scale 3 and a second scale 4a are disposed on a scale base 2. The second scale 4a is formed of plural graduation blocks 4a1-4an having the number of graduations gradually increased or decreased with each graduation division lambda, and with the left or right end of the graduation between the respective graduation blocks as a reference position, the division of the respective graduation blocks 4a1-4an is integer times of lambda.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a scale device of the present invention,
In particular, it relates to improvement of an absolute type scale device suitable for use in a numerically controlled machine tool or the like.

[0002]

2. Description of the Related Art In general, many conventional scale devices are of the incremental type, and an origin signal generating means is added to the scale device of such a type so that the absolute position can be read out by the absolute type. A scale device made in is known. An example of such a scale device is shown in FIG.
A description will be given using A and B.

FIG. 3A shows a plane of an absolute type scale device and its circuit configuration, and FIG. 3B shows a side view of the scale and the head portion.

In FIGS. 3A and 3B, reference numeral 1 denotes a scale device as a whole, and a scale base 2 made of a strip-shaped plate material such as a screw.
The first scale 3 is arranged in a track shape in the longitudinal direction of the scale base 2 by applying a magnetic medium thereon, vapor deposition, plating or the like. A scale signal of wavelength λ is recorded on the first scale 3 of this magnetic medium along the longitudinal direction.

Further, a magnetic medium to be the second scale 4 is provided at a substantially central position on the lower side of the first scale 3 of the scale base 2 by coating, vapor deposition, plating or the like for absolute position detection. The signal is recorded corresponding to the position of the first scale signal λ.

Although FIG. 3A shows a structure in which one second scale 4 is arranged at a substantially central position in the longitudinal direction of the first scale 3, a plurality of these second scales 4 are appropriately provided. There is also known one which is arranged at a position, and only one of them is selected and used as an origin signal generating means as an absolute value position origin.

A first detection head 5 is arranged to face the first scale 3 and a second detection head 6 is arranged to face the second scale 4. The displacement of the relative position is measured by moving the first detection head 5 in the longitudinal direction of the first scale 3. This measuring method is a widely known method. First
The detection head 5 outputs a detection signal S ₁ corresponding to the relative displacement for relative position detection.

The second detection head 6 is also the first detection head 5.
When it is moved in the longitudinal direction of the first scale 3 in conjunction with, the detection pulse S ₂ is output when the second detection head 6 passes the position of the second scale 4. The detection signal S ₁ corresponding to the relative displacement output from the first detection head 5 is supplied to the first detection circuit 7, and the detection pulse S ₂ output from the second detection head 6 is the second detection circuit. 8 are supplied.

The detection pulse S ₂ supplied to the second detection circuit 8 outputs the gate pulse S ₃ and supplies it to the λ gate circuit 9. Since the λ gate circuit 9 is supplied with the continuous detection signal S _{1 of} λ cycle corresponding to the relative displacement when the first detection head 7 moves from the first detection circuit 7, only one λ signal is supplied. It is gated by the gate pulse S ₃ . Of course, the second detection head 6 is preselected so that the output position of the detection signal S ₁ of the λ cycle and the output position of the detection pulse S ₂ are at appropriate positions.

The origin signal S ₄ indicating the absolute position is output from the λ gate circuit 9 and supplied to the preset circuit 10. Since the detection signal S ₁ corresponding to the relative displacement is supplied from the first detection circuit 7 to the preset circuit 10, by presetting this measured value to a predetermined value and displaying it on the display unit 11, the absolute scale device 1 Is configured.

[0011]

The scale device described in the above-mentioned conventional structure is an absolute scale, but the absolute position can be read only at the position where the second scale 4 is arranged. In order to attach the associative scale device to a machine tool or the like for position control and start the operation, first, the machine is moved, and the origin alignment is performed so that the second detection head 6 passes through the second scale 4 position. This is a problem that must be done, especially in the case of a machine that has a long operating range, this home position adjustment time becomes a loss time.

Further, since the origin position differs depending on the machine, there is the trouble that the detection pulse S ₂ must be recorded by aligning the position of the second scale 4 with the required position suitable for the machine.

If the second scale 4 is provided at a plurality of places, a detection circuit and a selection circuit for selecting one detection pulse S ₂ from the plurality of second scales 4, 4, ... Are required. However, there is a problem that the circuit becomes complicated.

The present invention is intended to provide a scale device which solves the above problems, and the purpose thereof is to determine the first position from the initial position of the first and second detection heads.
Also, an absolute value is preset only by the number of pulses in a state where the relative movement distance between the second detection heads 5 and 6 and the first and second scales 3 and 4 is small, so that a scale device having a simple circuit configuration is obtained. It is the one.

[0015]

As shown in FIG. 1, the scale device of the present invention has a first graduation part 3 provided with continuous graduations at a constant interval λ, and a first graduation part 3 in parallel to the longitudinal direction of the scale portion 3 of and a second scale part 4a in which one or / and the memory block 4a ₁ ～4An imparted with different numbers of graduations arranged in a plurality predetermined intervals Then
A plurality of memory blocks 4a ₁ to 4A _n of the second scale part 4a
Each graduation interval inside is made up of λ, and graduation block 4a
₁ each of intervals of to 4A _n is the scale block 4a ₁ to 4
as a reference position of the right end or left end of the scale a _n, it is obtained form an integral multiple of lambda.

As shown in FIG. 1, the second scale device of the present invention has a first graduation portion 3 provided with continuous graduations at a constant interval λ, and the first graduation portion. 3 longitudinally in parallel scale 2 and a second scale portion 4a one or / and the memory block 4a ₁ to 4A _n imparted with different numbers of graduations are disposed a plurality predetermined intervals
And the first and second detection heads 5 and 6 arranged in parallel to face the first and second scale portions 3 and 4a, and the first and second
First and second detecting means 7 and 8 for detecting the scale signal and the gate signal from the detecting heads 5 and 6, and the absolute position from the scale signal and the gate signal from the first and second detecting means 7 and 8. The gate means 9 for obtaining a signal and the preset value processing means 14 for setting a preset value corresponding to the number of output pulses of the absolute position signal obtained from the gate means 9 are provided, and are obtained from the first detecting means 7 and 8. The relative change position is preset by the absolute value position signal obtained from the preset processing means 14.

[0017]

According to the scale device of the present invention, the second graduation portion (scale) is composed of a plurality of graduation blocks, the graduations in the block are numbers from 1 to n, and preset by the number of pulses counting this number. Since the value is set, an extremely simple circuit can be configured, and an absolute scale device in which the relative moving distance between the detection head and the scale from the initial state is small can be obtained.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the absolute scale device of the present invention will be described in detail below with reference to FIGS. FIG. 1 is an overall configuration diagram of the scale device, and second is an explanatory diagram showing an enlarged portion of the scale and its waveform relationship.

FIG. 1A is a plan view of the scale base shown in FIG. 1B.
Shows a side view schematically. Reference numeral 15 indicates a scale device of this example which is an absolute type as a whole. The scale base 2 is a strip-shaped plate material having the same structure as the conventional one, and a first scale 3 similar to that shown in FIG. 3 is formed on the scale base 2 along the longitudinal (measurement) direction.

That is, the signal S ₁ ′ having the wavelength λ is recorded on the magnetic medium coated, vapor-deposited or plated on the scale base 2, and the scale is formed in the measuring direction over the measuring length of the scale.

Similar to the first scale 3, the second scale 4a is arranged below the first scale 3 in parallel along the measuring direction. Therefore, the second scale 4a is coated with a magnetic medium, vapor-deposited, plated, or the like, and the signal S ₂ ′ of the wavelength λ is recorded on the magnetic medium to form a scale in the measuring direction.

The second scale 4a has one (N = 1) and / or a plurality (N = 2, N =) as shown in FIGS. 1 and 2A.
3 ..., N = n) scale blocks 4a ₁ , 4a ₂ , 4a
₃ ... 4a _n are arranged at equal intervals (x) in the measurement direction.

These scale blocks 4a ₁ , 4a ₂ , 4a
The number N of ₃ ... 4a _n scales continuously with 1, 2, 3 ... n or N = n, n-1, n-2 ... 2, 1 so that it decreases continuously. It is set.

In FIGS. 1 and 2, a plurality of scale blocks are shown.
4a₁, 4a₂, 4a₃4a _nNext to each other on the scale
Position reference for scale block 4a₁, 4a₂, 4a₃‥‥‥
4a _nRight or left end of the scale (left end in Fig. 1 and Fig. 2)
And a plurality of scale blocks 4a₁, 4a₂, 4a₃‥‥‥
4a_nThe intervals between the scales are λ.
Set the graduation interval in the circle to an integral multiple of λ such as 2λ, 3λ, etc.
Good.

The first and second scales 3 and 4a described above
The magnetic medium is arranged on the scale base such as glass to form the scales S ₁ ′ and S ₂ ′. The scale base 2 itself is composed of the magnetic medium, or the scale base 2 made of glass has a λ spacing. It is also possible to print the first scale 3 and the second scale 4 and to extract the detection signal optically via a photo interrupter or the like.

Such first and second scales 3 and 4
The first and second detection heads 5 and 6 are interlocked with respect to a and are movable in the measurement direction (longitudinal direction of the track). That is, one is fixed and the other is movable.

The relative positions of the first and second detection heads 5 and 6 are arranged at positions where the scale signal P ₁ and the gate signal P _{2 of} FIGS. Two detection heads 5 and 6 are held and fixed so as to move together.

The detection signal S ₁ corresponding to the relative displacement detected by the first detection head 5 is the same as in the conventional example shown in FIG.
Is supplied to the detection circuit 7 and the preset relative displacement amount is displayed on the display unit 11 via the preset circuit 10.

The detection output of the second detection head 6 is the detection pulse.
Space S₂Is output to the second detection circuit 8.
It From the second detection circuit 8 to the λ gate circuit 9,
Ruth P ₂(FIG. 2C) is output from the first detection circuit 7.
Is the scale λ signal P in the λ gate circuit 9.₁(Fig. 2B)
It is made to be paid. The structure during this period is the same as in FIG.
However, the detection pulse supplied to the second detection circuit 8
Space S₂Is the scale block 4a of the second scale 4a₁, 4
a₂4a_nThe second detection, which depends on the number of
From the circuit 8, the gate pulse P as shown in FIG.₂Output
To be done.

In this example, the output end of the λ gate circuit 9 is connected to the first and second switch circuits 12 and 13, and the output end of the first detection circuit 7 is the first and second switch circuits 12 and 13.
13 and 13 are respectively connected to the preset position processing circuit 14, the output terminal of the first switch circuit 12 is connected to the second switch circuit 13, and the output terminal of the second switch circuit 13 is connected to the preset processing circuit 14. It is connected. or,
The output terminal of the preset value processing circuit 14 is the preset circuit 1
It is connected to 0.

The operation of the above configuration will be described below with reference to FIGS.
Described in. First and second detection heads 5 and 6 and first
When the second scales 3 and 4a are moved relative to each other in the measurement direction, the first detection head 5 supplies the detection signal S ₁ corresponding to the relative displacement to the first detection circuit 7. The first detection circuit 7 and the preset circuit 10 are composed of a scale λ signal circuit, an interpolation circuit, an up / down counter, etc., and the relative displacement amount between the first scale 3 and the first detection head 5 as in the conventional case. Is detected and displayed on the display block 11, and as shown in FIG. 2B, the scale λ signal P ₁ corresponding to the λ period of the first scale 3 is output, and the λ gate circuit 9 and the first and second It is supplied to the switch circuits 12 and 13.

The second detection head 6 has the second scale 4a.
When passing through the memory block 4a _1, 4a ₂ ‥‥ above 4a _n, the detection pulse S ₂ corresponding to the number of graduations of the scale block 4a _1, 4a ₂ ‥‥ within 4a _n is supplied to the second detection circuit 8 From the detection circuit 8, the gate pulse P shown in FIG.
₂ is output to the λ gate circuit 9.

Since the positional relationship between the first and second detection heads 5 and 6 is set so that the scale λ signal P ₁ and the gate pulse P ₂ are synchronized with each other, only when the gate pulse P ₂ is generated. From the λ gate circuit 9, λ shown in FIG.
The gate output signal P ₃ is output and supplied to the first and second switch circuits 12 and 13.

In the above operation, the initial position of the second detection head 6 is the scale blocks 4a ₁ and 4a _{2 of} the second scale 4a.
In the case where the movement is started at the intermediate position of 4a _n , the initial position is the scale blocks 4a ₁ , 4a ₂ ... 4
scale block 4a ₁ when located on a _n, 4a ₂ ‥‥
The gate pulse P ₂ corresponding to the number of graduations of 4a _n cannot be output, which causes a malfunction.

The above-mentioned first and second switch circuits 12 and 13 are set to the second position in the initial position state when the control machine or the like is powered on.
The detection head 6 of the scale block 4a ₁ , 4a ₂ ... 4a
_{Even if} it is on _n , it works so that the absolute value can be preset normally.

That is, from the initial state, the second detection head 6
First scale block 4a₁, 4a ₂4a_nPass through
Λ gate output signal P sometimes obtained₃Is the correct number of pulses
In some cases, it may not be possible to use the second switch as an absolute position signal.
The second detection head is configured so that it is not output from the latch circuit 13.
Do 6 is the second scale block 4a₁, 4a₂4a _n
Λ gate output signal P obtained when passing₃Absolute position
Signal P_FourIs output from the second switch circuit 13.

Also, after the second λ gate output signal P ₃ is output, the third and fourth graduation blocks 4a ₁ and 4a.
₂ ... The first and second switch circuits 12 and 13 are operated so that the λ gate output signal P _{3 of} 4a _n is not output.

The first switch 12 has a first detection circuit 7
From the scale λ signal P ₁ and the λ gate circuit 9 from the λ gate output signal P _3, but in the initial state when the scale device 15 is powered on, the first switch circuit 12 has the λ signal.
The gate output signal P ₃ is gated so as to "on".
Further, even if only the scale λ signal P ₁ is inputted, or even if the scale λ signal P ₁ and the λ gate output signal P ₃ are simultaneously inputted, the λ gate output signal P _{3 of} the first switch circuit 12 is inputted.
The gate is designed to be "on".

Assuming that the first and second detection heads 5 and 6 and the first and second scales 3 and 4a relatively move in the scale measuring direction from such an initial state, for example, in FIG. When the second detection head 6 starts passing through the arbitrary first graduation block 4a ₃ of the second scale 4a, the scale λ signal P ₁ and the λ gate output signal P ₃ are synchronized with each other.
And to the second switch circuits 12 and 13.

The first switch circuit 12 is set so that its output is in the "off" state when the input gate of the λ gate output signal P ₃ is "on".

Therefore, when the second detection head 6 finishes passing the arbitrary first graduation block 4a ₃ , the λ gate output signal P ₃ is not input to the first switch circuit 12, and the scale λ signal is input. Although only P ₁ is input, in that state, the input gate of the λ gate output signal P ₃ is set to the “off” state, and the output changes from the “off” state to the one-pulse ON signal P _ON . The signal is output to the second switch circuit 13 in the next stage, and after this one pulse is output, the input gate is held in the “off” state.

As described above, since the input gate of the λ gate output signal P ₃ in the first switch circuit 12 is in the "OFF" state, the second detection head 6 continues to operate the second, third and third switches.
Even after passing through the second graduation blocks 4a ₄ and 4a ₅ , the λ gate output signal P ₃ is not input to the first switch circuit 12 and the output remains in the "OFF" state. That is, the first switch circuit 12 operates, for example, only once after passing through the first graduation block 4a ₃ , and the other graduation blocks 4a ₄ and 4a.
₅ does not work even when passing over ‥‥ 4a _n.

The second switch circuit 13 has the λ gate output signal P in the initial state when the scale device is powered on.
_{The 3} input gates are set to be "off".

When the second detection head 6 has passed the arbitrary first scale block 4a ₃ and has received the _ON signal P _ON from the first switch circuit 12, the λ of the second switch circuit 13 is received. input gate of the gate output signal P ₃ is set to "on" state from the "off" state.

Therefore, the second detection head 6 continuously moves,
Begins to pass through the second memory block 4a ₄ input gate of the λ gate output signal P ₃ of the second switch circuit 13 starts operation, is λ gate output signal P ₃ is input, the second switch circuit 13 The absolute value position signal P ₄ is supplied to the preset value processing circuit 14.

In the second switch circuit 13, the scale λ from the first detection circuit 7 is moved along with the movement of the second detection head 6.
Although the signal P ₁ is input, the input gate of the λ gate output signal P ₃ is in the “ON” state in the second switch circuit 13 when the scale λ signal P ₁ and the λ gate output signal P ₃ are input at the same time. Is designed to hold.

When the second detection head 6 has finished passing the arbitrary second scale block 4a ₄ , for example, the λ gate output signal P ₃ is not output and only the scale λ signal P ₁ is input. The input gate of the λ gate output signal P ₃ is in the “off” state.

Even when the second detection head 6 continuously moves and passes through the third and fourth graduation blocks 4a ₅ , 4a ₆ ..., The input gate of the λ gate output signal P ₃ is "off". Therefore, the absolute position signal P ₄ is not output to the preset processing circuit 14.

That is, the first and second switch circuits 12 and 13 cause the scale blocks to be moved only when the cooperating first and second detection heads 5 and 6 pass the second scale blocks 4a _{1 to} 4a _n. The absolute position signal P ₄ corresponding to the number of graduations 4a _{1 to} 4a _n can be output to the preset value processing circuit 14. This state does not change unless the power is turned off. Such first and second switch circuits can be easily configured by a logic circuit or the like.

The preset value processing circuit 14 supplies an absolute scale device which supplies a preset signal digitized corresponding to the number of pulses of the input absolute position signal P ₄ to the preset circuit 10 and displays the absolute value on the display unit 11. obtain.

For example, as shown in FIG. 1, first and second detection
Heads 5 and 6 are scale blocks 4a ₂And 4a₃Between
As a result, the power is turned “on” and the first and second detection heads 5 are
And 6 have moved to the right. Scale in this state
Number N = 4 scale block 4a _FourThe second detection head 6
When it starts passing, the preset value processing circuit 14
Signal P_FourStarts to input, and is cut off when the N = 4 scale finishes passing.
Position signal P_FourWill stop. That is, in this case, N = 4 scale
4 pulse absolute position signal P_FourIs the preset value processing times
Input to path 14, but generally x = between graduation blocks
, N = scale block signal, λ = recording pitch, x (N-1) + λ (N-1) (1) The preset signal corresponding to the equation (1) is output.

Similarly, as shown in FIG. 1, the first and second detections are performed.
Heads 5 and 6 are scale blocks 4a ₂And 4a₃Between
Therefore, when the first detection head 6 moves to the left, a preset signal corresponding to the equation (2) of x (N-1) (2) is output.

To set the preset value in the left-right direction, the direction discrimination signal P ₅ supplied from the up / down counter in the first detection circuit 7 to the preset value processing circuit 14 is set.
Done by.

For example, in FIG. 1, the scale block interval x
= 10 mm, recording pitch λ = 100 μm, the position of the scale block 4a ₁ is “zero position”, and the setting resolution is 1 μm.
Consider the preset value when the unit is used.

When the second detection head 6 moves to the right in FIG. 1 and begins to pass the second graduation block 4a ₄ ,
4 pulses are output from the switch circuit 13 as the absolute position signal P _{3 and} are supplied to the preset value processing circuit 14. In this case, each pulse has the following preset value corresponding to the equation (1). .

[0056]

After 4 pulses, as described above, the absolute position signal P ₃ is generated even if the second detection head 6 continuously passes through the third and fourth scale blocks 4a ₅ , 4a ₆ ... 4a _n . Does not occur, the preset value of the fourth pulse becomes the final preset value. That is, the fourth pulse position is 3x + 3λ from the “zero position” of the scale block 4a _{1 according to} the equation (1).
= 30,300.

In this way, when the number N of signals of the scale blocks 4a _{1 to} 4a _n is plural and the second detection head 6 moves to the right with respect to the measuring direction, for example, by the rightmost end of the scale block 4a ₄ . The preset circuit 10 is generated by the absolute position preset signal P ₆ according to the last preset value generated.
Is preset.

Similarly, when the second detection head 6 moves to the left in the measurement direction in FIG. 1, the absolute position signal P ₄ is output when the second detection block ₆ passes the second scale block 4a ₁ .
According to the equation (2), x (N-1) = 0.

The second detection head 6 shown in FIG. 1 is arranged in the initial state between the scale blocks 4a ₅ and 4a ₆ ,
If you move to the left and outputs four pulses as an absolute position signal P ₃ in the memory block 4a ₄ position. The preset value in this case is as follows according to the equation (2).

[0061]

[0062] As in this case, a pulse when the second detection head 6 second scale 4a is moved relatively leftward generated by the leftmost signal of the scale block 4a ₁ to 4A _n final It becomes a preset value.

In the graduation block 4a ₄ of the above example, the leftmost graduation position is 3x away from the N = 1 "zero position" of the first graduation block 4a ₁ and its value is (x (N-
1) = 30.000.

As described above, in the present invention, the final preset signal used in the plural scale blocks differs depending on the direction at the time of detecting the absolute position.

In the above structure, the initial position of the second detection head 6 is the first and second graduation blocks 4a ₁ and 4a _2.
If the second detection head 6 comes into contact with the end detection sensors arranged at the left and right ends of the scale base 2, the first scale is not shown, if it is between n-1 and n scale blocks. Without passing through the block, the first scale block 4a ₁ or the nth scale block 4a
_The absolute position signal P ₃ is output at the _n position.

Therefore, according to the present invention, no matter where the first and second detection heads 5 and 6 are placed, 2x (up to 3x in the case of FIG. 1) first and second after the power is turned on in the initial state. If the relationship between the two detection heads 5 and 6 and the first and second scales 3 and 4a is relatively moved, an absolute scale device can be obtained by presetting absolute position values.

In the above embodiment, λ = 100 μm, x = 1
Although the example of 0 mm has been described, it is obvious that the values of λ and x can be appropriately selected.

Further, in FIG. 1, the scale block 4a₁~ 4a_n
The interval x between the plural scale blocks 4a ₁~ 4a_nLeft edge
Based on the scale on the right, it was set at equal intervals.
It may be evenly spaced. The present invention is configured as described above.
The first and second detection heads 5 and 6 and the first and second detection heads
Reduce the relative movement distance of scales 3 and 4a from the initial state.
Lost time to set the origin position
Can be shortened. Equipment used as before
Avoid the hassle of changing the origin position according to
You get what you can. Also, the absolute position signal P₃
The preset circuit is preset according to the number of pulses
Therefore, a simple circuit can be constructed at low cost.

[0069]

According to the scale device of the present invention, the following effects can be obtained. (1) Absolute value can be preset when the relative movement distance of the head and scale is smaller than in the initial state at an arbitrary position compared to the conventional origin method. (2) As in the conventional origin method, it is not necessary to give the origin to the designated position for each user request. (3) is only to set a preset value by the number of pulses of the absolute position signal P _3, can in principle inexpensively configuration simpler circuit configuration.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a scale device of the present invention.

FIG. 2 is a scale pattern used in the scale device of the present invention and an output waveform diagram thereof.

FIG. 3 is a configuration diagram of a conventional scale device.

[Explanation of symbols]

1,15 Scale device 3,4,4a 1st and 2nd scale 4a _{1 to} 4a _n Scale block 5,6 1st and 2nd detection heads 7 and 8 1st and 2nd detection circuits 12 and 13th 1st and 2nd switch circuit 14 Preset value processing circuit

Claims (6)

[Claims] 1. A first graduation portion provided with continuous graduations at a constant interval λ, and one or / and a plurality of different numbers of graduations provided in parallel to the longitudinal direction of the first graduation portion. A plurality of graduation blocks are provided at a predetermined interval, and the graduation intervals in each of the plurality of graduation blocks of the second graduation unit are λ, and each graduation block has a graduation interval of λ. The scale device is characterized in that each interval is an integral multiple of λ with the right end or the left end of the scale of the scale block as a reference position. 2. The number of graduations of a plurality of graduation blocks forming the second graduation portion is arranged so as to continuously increase or decrease with respect to an adjacent graduation block. Scale equipment. 3. A first detection head and a second detection head are arranged in parallel so as to face the first scale part and the second scale part, and the first and second detection heads are arranged in the first and second scales. Is configured so as to be displaced in the longitudinal direction of the graduation portion in cooperation with each other, the absolute position is detected by the detection circuit connected to the output ends of the first and second detection heads, and the absolute value is preset by the detection signal. The scale device according to claim 1, wherein: 4. A first graduation portion provided with continuous graduations at a constant interval λ, and one or / and a plurality of different numbers of graduations provided in parallel to the longitudinal direction of the first graduation portion. A scale having a second graduation portion in which a plurality of graduation blocks are arranged at predetermined intervals; first and second detection heads arranged in parallel to face the first and second graduation portions; First and second detecting means for detecting a scale signal and a gate signal from the first and second detecting heads, and a gate for obtaining an absolute position signal from the scale signal and the gate signal from the first and second detecting means. Means and a preset value processing means for setting a preset value corresponding to the output pulse number of the absolute position signal obtained from the gate means, and the relative change position obtained by the first detecting means is preset processing means. Yo It is made to preset absolute value signal obtained scale device according to claim. 5. The scale device according to claim 4, further comprising switch means for obtaining only an absolute value position signal obtained from the second graduation block of the second graduation portion via the gate means. . 6. A direction discrimination signal from said first detecting means is supplied to said preset value processing means, and a relative displacement amount value obtained from said first detecting means is preset according to a relative displacement direction. The scale device according to claim 4, wherein: