JPS60214216A - Level sensor - Google Patents

Abstract

PURPOSE:To detect a level position with high accuracy by measuring with phase measuring means connected to a common electrode a sinusoidal wave impressed to two pairs of electrodes whose areas dipped in a liquid differ in accordance with an inclination. CONSTITUTION:When a container 1 is in a level position, the areas under the liquid face of electrodes 3, 4, 5, 6 are the same, but when the container 1 is inclined from a water level, the areas under the liquid surfaces of the electrodes 3, 4, 5, 6 vary. In case the direction of the electrodes 3, 4 is denoted as a direction X and the direction of the electrodes 5, 6 as a direction Y, and when a liquid 2 is inclined thetaX in the direction X and thetaY in the direction Y the phase phiY of the output signal of an amplifier 14 on impressing a specific signal to the electrodes 3, 4 and the phase phiX of the output signal of the amplifier 14 on impressing to the electrodes 5, 6 are found. The phase phiY depends on an angle thetaY corresponding to the area ratio of under the liquid surface of the electrodes 3 and 4 and the phase phiX depends on an angle thetaX corresponding to the area ratio of under the liquid surface of the electrodes 5 and 6.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a horizontal sensor that two-dimensionally detects inclination from the horizontal.
It can be used with devices that are designed to obtain fixed values.

(Background of the invention) In conventional surveying instruments, the surface of mercury sealed in a container is a total reflection surface, and this reflective surface is placed in the optical path between the emitter and the receiver, and the container, the emitter, and the receiver are used for surveying. A device has been put into practical use that is fixed to a surveying instrument and converts a change in the position of light from a projector that moves on the light-receiving surface of a light receiver as the surveying instrument is tilted into the amount of tilt of the surveying instrument.

However, in such a device that reads the inclination of the mercury surface with respect to the main body of the device as a change in the position of light on the light receiving surface, in order to improve accuracy it is necessary to increase the distance between the detection position and the mercury surface, and the horizontal sensor is The drawback was that it was too large. Additionally, there is a problem in that handling of mercury is undesirable from the standpoint of pollution.

(Objective of the Invention) An object of the present invention is to solve the drawbacks of such conventional devices and to obtain a horizontal sensor that is small and capable of detecting the entire horizontal position with high precision.

(Summary of the Invention) The present invention is characterized in that a conductive liquid is completely enclosed in a container, and a first conductive liquid is placed in a first inclination direction so that the area of the portion immersed in the liquid varies as the container inclines. A second electrode is mounted in a second inclination direction different from the first inclination direction. A fourth electrode is provided, and these first, second, and third electrodes are arranged. Third. The common electrodes are all disposed at a position equidistant from the fourth electrode and always immersed in the liquid regardless of the tilt of the container, and the second electrode and the third
゜Signal applying means for selectively applying sine waves having different phases to the fourth electrode and the selected electrodes, a phase measuring means connected to the common electrode, and a phase measuring means connected to the common electrode. The phase measured by the phase measuring means when a sine wave is applied to the second electrode, and the third.
This is a horizontal sensor in which calculation means for measuring the tilt direction and amount of the container from the phase measured by the phase measuring means when a sine wave is applied to the fourth electrode is connected to the phase measuring means.

(Example) FIG. 1 is a perspective view showing a detection section of a first embodiment of the present invention, and FIG. 2 is a block diagram of a first embodiment of the present invention using the detection section of FIG. 1. .

In FIG. 1, a nearly cuboidal container 1 is filled with a conductive liquid 2 having an appropriate resistance value to about half its extent.

A total of four electrodes 3, 4, 5.6 of the same shape, one on each side, are placed inside the four sides of the container l and in the center of each side, so that when the surface of the liquid 2 is horizontal, It is provided so that the surface of the liquid 20 is located at an intermediate position, and a common electrode 7 is provided at the inner center of the bottom surface.

FIG. 2 is an electrical circuit diagram schematically showing the detection unit Ai in FIG. ing. The drive circuit 8 is composed of a sine signal oscillator 9, a phase shifter lO for shifting the output signal of the oscillator 9 by 90 degrees, an interlocking switch 11, and inverting circuits 12 and 13. The interlocking switch 11 connects all output terminals P1 of the oscillator 9 to the phase shifter l.
The output terminal of the oscillator 9 is connected to the input terminal of the inverting circuit 12, and the output terminal of the phase shifter 10 is connected to the input terminal of the gold inverting circuit 13. The output terminal of the inversion circuit 12 is connected to the terminal Ps, and the output terminal of the inversion circuit 13
The output terminal of is connected to terminal P4.

Electrode 3 is connected to terminal P, IC, electrode 4 is connected to terminal P, electrode 5 is connected to terminal P3, and electrode 6 is connected to terminal P4. Electrode 3 is connected via resistance rak due to liquid 2, electrode 4 is connected via resistance rb' due to liquid 2, electrode 511- is via resistance rck due to liquid 2, electrode 6 is connected via resistance rd'i due to liquid 2.
They are each connected to a common electrode 7 via z. Common electrode 7
An amplifier 14 having a feedback resistor R is connected to the amplifier 14, a phase measuring circuit 15 is connected to the amplifier 14, and an arithmetic circuit 16 is connected to the phase measuring circuit 15.

The signal from the measurement start signal generator 17 drives a pulse generator 18 that outputs a pulse signal that repeats high and low levels at regular intervals, and is input to the arithmetic circuit 16. The pulses from the pulse generator 18 are input to the switching circuit 19 of the interlocking switch 11 using a relay or the like, and are also input to the arithmetic circuit 16. The switching circuit 19 switches the interlock switch 11 from the illustrated position when the input signal is at a high level.

A ROM 20 is also connected to the arithmetic circuit 16, and the arithmetic circuit 16 is connected to the phase measuring circuit 15. Measurement start signal generator 1
7. The pulse generator 18 performs arithmetic processing according to the signals from the ROM 20, and measures the entire tilt direction and amount.
It is displayed on the display 21. Note that the container 1 does not have to be approximately cubic, and may be a container whose opposing sides are inclined. In that case, the change in the liquid level relative to the electrode with respect to one foot of inclination is cubic, and jl ) is also large, so sensitivity can be increased.

Next, the operation of the above embodiment will be explained. When the container 1 is in a horizontal position, the areas below the liquid surface of the electrodes 3, 4, 5.6 are the same, but when the container 1 is tilted from the horizontal position, the areas of the electrodes 3, 4, 5.6 are the same.
The area under the liquid surface of No. 6 is different.

Now, as shown in Fig. 3, if the direction of the electrode 3.4 is the entire X direction and the direction of the electrode 5.6 is the iY direction, the liquid 2 is θX e in the X direction by considering the container 1' (j reference). Y
It will be tilted by θy in the direction. Note that t in Fig. 3 is when the container 1 is horizontal (the liquid level at this time is indicated by a wavy line).
The distance from the center of the liquid surface to each side of the container 1 (the distance from the center of the liquid surface to the center of each electrode 3° 4.5.6).

Each electrode is 3°4.5 when the container l is tilted as shown in Figure 3.
．． The area under the liquid level of No. 6 is as shown in Figure 4, which shows the side surface of container L (the straight line m indicates the liquid level when container L is horizontal, and the broken line m indicates the liquid level when container L is tilted). ] , the area Sa of the electrode 3 below the liquid surface is D・(H−a),
The area sb below the liquid surface of electrode 4 is D・lH+6), electrode 5
The area Sc below the liquid surface of % electrode 6 is D·(H−c), and the area Sd below the liquid surface of the % pole 6 is D·(H−d) from FIG. 4(d).

However, in FIG. 4, D is the width of each electrode 3, 4, 5.6, and H is the length of each electrode 3, 4, 5.6 below the liquid surface when the container I is horizontal.

a is the average amount of movement of the liquid level at electrode 3, b is the average amount of movement of the liquid level at electrode 4, C is the average amount of movement of the liquid level at electrode 5, and d is the average amount of movement of the liquid level at electrode 6. .

Here, if the movement amount a*b*ctdk is expressed using the symbols in FIG. 3, &=t-L&nθy, b=L-tanθ
y, c=L-tanθx, d==t-tanθ
It becomes X.

The resistance values ra, rb, re, ra between each electrode 3, 4, 5.6 and the common electrode 7 are as follows:
Since it almost depends on the surface & below the liquid level of 4°5.6, 1
1 1 ra==a HSa s rb””' ” ' Si)
#re−α' B, #rd=α・Sd 'c.

Therefore, electrode 311Cginwt * cosw to electrode 4
When t f is applied, the output signal of the amplifier 14 becomes RR −sinwt+−coswt ra rb where ψy=tan ” ri rb .

Moreover, electrode 5 iC-sinwt, 'ii to electrode 6-
If coswti is applied, the output signal of the amplifier 14 is, however, 91X: tan-Ir! −d.

That is, electrode 3. The phase ψa of the output signal of the amplifier 14 when a predetermined signal is applied to the electrode 4 and the electrode 5. pole 6
Considering the phase ψ of the output signal of the amplifier 14 when a predetermined signal is applied to angle θy
The phase ga corresponds to the area ratio below the liquid surface of the electrodes 5 and 6, and therefore depends on the angle θ8 in FIG.

Therefore, if the relationship between the angle θ and the phase ψ and the relationship between the angle θ7 and the phase ψ are measured in advance and stored in the ROM 20, the phase signal from the phase measurement circuit 15 and the phase signal from the pulse generator 18 can be The arithmetic circuit 16 reads out the corresponding angle θ8°θy of the ROM 20 based on ψ and ψa obtained from the signal indicating which pair of electrodes 3 and 4 or 5 and 6 the signal is applied to. be able to. Once the angles θ and θ are determined, it is easy to determine the direction of inclination and the amount of inclination in that direction. That is, the inclination direction α is 45
≦tan''5≦90, and the operation of θX is summarized and shown as a flowchart in FIG.

Next, a second embodiment of the present invention is shown in FIG. 6 and FIG. 7, which is a sectional view taken along line A-A' in FIG. 6, and will be described below. In the second embodiment of the present invention, a circular bubble tube 22 is formed by a container 1 filled with a conductive liquid 2, and two circular bubble tubes 22 are placed at positions equidistant from the apex in a direction substantially orthogonal to the curved surface 22a of the container 1. A total of four pairs of electrodes 3, 4, 5.6i with the same area are arranged, and a common electrode 7 is provided on the lower surface at the same distance from the four electrodes 3, 4, 5.6. . Electrodes 3, 4, 5, 6, 7 of the first embodiment and electrodes 3, 4° 5.6 of the second embodiment
, 7 performs exactly the same function. When the bubble tube 22 is in a horizontal position (amount of inclination), the bubble 23 is centered on the apex of the curvature surface 22a, so the areas of the electrodes 3, 4, and 5.6 immersed in the liquid are equal. When the bubble tube 22 is tilted, the bubble 23 moves in a direction opposite to the tilt direction according to the amount of tilt, as shown in FIGS. 6 and 7. Therefore,
The area of the portions of the four electrodes 3, 4, 5.6 immersed in the liquid changes depending on the inclination of the bubble tube 22. 4
The processing circuit for the signals applied to the three electrodes 3, 4, 5.6 and the signal obtained from the electrode 7 can be exactly the same as that shown in FIG.

In addition, in FIG. 2, the electrode 31c sinwt, the electrode 4
coswt, electrode 5 K-alnwt, electrode 6
K -coswt'i was applied, but sinw was applied to electrode 5.
t and coswti may be applied to the electrode 6, in which case the inverting circuits 12 and 13 become unnecessary. Furthermore, electrode 3
, 4 need not be 90 degrees different from each other, and may have other phase relationships that are not close to zero.

Furthermore, as shown in Fig. 2, if the application of signals to the electrodes 3, 4 and 5, 6 can be done completely automatically, it can be used as an automatic leveling mechanism for surveying instruments, etc. In this case, Although leveling can be easily performed automatically, it is of course possible to manually switch the interlocking switch 11.

(Effects of the Invention) As described above, by implementing the present invention, it is possible to obtain a horizontal sensor 7 which is small in size and can detect the horizontal position with high precision.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the detection unit of the first embodiment of the present invention, Fig. 2 is a block diagram of the first embodiment of the invention using the detection unit of Fig. 1, and Fig. 3 is a diagram of the liquid level. Perspective view showing inclination t, Fig. 41
- is a developed diagram showing the relationship between the inclined liquid level and each electrode as shown in Fig. 3, Fig. 5 is a flowchart of the arithmetic circuit in the block diagram of Fig. 2, and Fig. 6 is a diagram of the second embodiment of the present invention. The plan view, FIG. 7, is a sectional view taken along line AA' in FIG. (Explanation of symbols of main parts) l... Container, 2... Conductive liquid, 3, 4, 5, 6,
... Electrode, 7... Common electrode, 8... Signal application circuit,
] 5... Phase measuring circuit, 16... Calculating means, 18.
...Pulse generator, 19...Switching circuit, 20...R
OM applicant Nippon Kogaku Kogyo Co., Ltd. Figure 2 7 Figure β

Claims (1)

[Claims] A conductive liquid is completely enclosed in the container, and a first . The second electrode is arranged in a second inclination direction different from the first inclination direction, and third and fourth electrodes are disposed in a second inclination direction different from the first inclination direction. 2nd, 3rd. A common electrode is disposed at a position equidistant from the fourth electrode and always immersed in the liquid regardless of the inclination of the container; the second electrode and the third
゜Signal applying means for applying sine waves having different phases to the selected electrodes is provided selectively to the fourth electrode, and a phase measuring means is connected to the common electrode. The phase measured by the phase measuring means when a sine wave is applied to the second electrode, and the phase measured by the third. A horizontal sensor, characterized in that a calculation means is connected to the phase measurement means for measuring the tilt direction and amount of the container from the phase measured by the phase measurement means when a sine wave is applied to the fourth electrode.