JP2020003307A - Water level detection system - Google Patents

Abstract

To provide a water level detection system with which it is possible to suppress the consumption of battery capacity and suppress the frequency of maintenance work for changing batteries.SOLUTION: A water level detection system 1 pertaining the present invention comprises: a water level detection electrode pair 110 with the longitudinal direction arranged in the vertical direction; a first reference electrode pair 111 having a lower end at the same height as the lower end of the water detection electrode pair 110 and shorter than the length of the detection electrode pair 110; an electrode drive circuit 185 for selectively amplifying a drive signal after application to the detection electrode pair 110 and first reference electrode pair 111; a data storage unit 186 for storing static capacitance value between each of the detection electrode pair 110 and first reference electrode pair 111; and a main control unit 180 for outputting an on/off command to the electrode drive circuit 185. The main control unit 180 determines whether to apply a drive signal to the detection electrode pair 110 on the basis of the static capacitance value of the first reference electrode pair 111 stored in the data storage unit 186 and outputs an on/off command to the electrode drive circuit 185.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a water level detection system used for grasping a water level at the time of rainfall on a road that is easily flooded.

  For example, roads such as underpasses are likely to be flooded structurally due to typhoons and rainwater from rainfall.Therefore, in each municipality, there is a need to grasp the water level during rainfall on roads that are easily flooded as described above. Exists.

In order to meet such needs, for example, Patent Document 1 (Japanese Patent Application Laid-Open No. 2017-181504) discloses a water level measurement device for measuring the water level of a road, which is provided on a road whose upper side is open. A unit and a communication aggregation unit to which information is wirelessly transmitted from the water level measurement unit, wherein the water level measurement unit is surrounded by a tubular body and detects a water level of a road flowing from an intake port of the tubular body. A capacitance-type water level meter having an electrode section for performing the operation and an output section for outputting water level information detected by the electrode section, and transmitting the water level information output from the output section of the water level meter to the communication aggregation unit. A water level information transmitting unit, a battery for supplying power to the water level meter and the water level information transmitting unit via a cable, the output unit of the water level meter, and the water level information transmitting unit. Means and a battery housed therein, and a waterproof case disposed above the electrode section of the water level gauge, wherein the communication aggregation unit transmits the water level information transmitted from the water level information transmitting means. There has been proposed a water level measuring device having a water level information receiving means for receiving and a communication means for transmitting the water level information received by the water level information receiving means to a server via a public telecommunication network.
JP, 2017-181054, A

  The water level measurement device described in Patent Literature 1 has a battery 50 that supplies power to the water level gauge 20 and the water level information transmission unit 40, and thereby directly connects a commercial power supply or the like that supplies power to the water level meter 20 and the water level information transmission unit 40. It is configured such that the connection operation can be omitted.

  As in the above-described water level measuring device, it is preferable to adopt a configuration in which a battery is used, water level information is acquired by this power source, and the water level information is transferred. However, in the water level measurement device described in Patent Literature 1, the battery constantly supplies power to the water level gauge and the water level information transmitting unit, so that the battery is greatly consumed and maintenance work for battery replacement is required. There have been problems such as the need to perform the operation frequently and the fact that the battery capacity is exhausted at the time of rainfall, which is important for grasping the water level of the rainwater, and the water level information cannot be obtained.

The present invention has been made to solve the above problems, and a water level detection system according to the present invention has a water level detection electrode pair whose longitudinal direction is arranged in a vertical direction, and the same height as the lower end of the water level detection electrode pair. A first reference electrode pair having a lower end and being shorter than the length of the water level detection electrode pair, and an electrode for selectively applying and amplifying a drive signal to the water level detection electrode pair and the first reference electrode pair. A drive circuit, a data storage unit that stores a capacitance value between the electrode pair of each of the water level detection electrode pair and the first reference electrode pair, and a main control unit that outputs an on / off command to the electrode drive circuit. The main control unit determines whether to apply a drive signal to the water level detection electrode pair based on the capacitance value of the first reference electrode pair stored in the data storage unit. Output an on / off command to the electrode drive circuit. The features.

  Further, the water level detection system according to the present invention further includes a data communication unit that transmits a capacitance value between the electrode pair of the water level detection electrode pair and the first reference electrode pair, and the main control unit includes: An on / off command is output to the data communication unit based on a capacitance value of the first reference electrode pair stored in the data storage unit.

  Further, the water level detection system according to the present invention further includes a second reference electrode pair having a lower end at the same height as an upper end of the water level detection electrode pair and having the same length as the first reference electrode pair. Wherein the electrode drive circuit selectively amplifies the drive signal also applied to the second reference electrode pair, and the data storage unit stores the capacitance value between the electrode pair of the second reference electrode pair. The main control unit determines whether to apply a drive signal to the second reference electrode pair based on the capacitance value of the first reference electrode pair stored in the data storage unit. And outputting an on / off command to the electrode drive circuit.

  In addition, the water level detection system according to the present invention further includes a data communication unit that transmits a capacitance value between each of the water level detection electrode pair, the first reference electrode pair, and the second reference electrode pair. The main control unit outputs an on / off command to the data communication unit based on a capacitance value of the first reference electrode pair stored in the data storage unit.

  Although the embodiment of the present invention has shown the configuration having the first reference electrode pair and the second reference electrode pair respectively, it has only the first reference electrode pair, and based on the capacitance value of the first reference electrode pair, A configuration in which the electrode drive circuit is turned on and off and an on / off command is output to the data communication unit is also possible.

  The water level detection system according to the present invention determines whether a drive signal is applied to the water level detection electrode pair and the second reference electrode pair and then amplified based on the capacitance value of the first reference electrode pair. Then, since the on / off command is output to the electrode drive circuit, according to such a water level detection system according to the present invention, when the water level is 0 during non-rainfall, power is supplied to the electrode pairs that need not be detected. Without doing so, it is possible to suppress the consumption of battery capacity, it is possible to reduce the frequency of maintenance work for battery replacement, and it is not possible to acquire water level information because the battery capacity is exhausted during rainfall It is also possible to suppress the probability.

  Furthermore, according to the water level detection system according to the present invention, the driving of the data communication unit that consumes a large amount of battery capacity can be limited to only during rainfall, and further reduction in battery capacity consumption can be realized.

FIG. 1 is a diagram illustrating a schematic configuration of a water level detection system 1 according to an embodiment of the present invention. It is a block diagram of water level detection system 1 concerning an embodiment of the present invention. It is a figure explaining arrangement of an electrode of water level sensor 100 concerning an embodiment of the present invention. FIG. 2 is a diagram showing a cross-sectional structure of a water level sensor 100. It is a figure showing an example of utilization of surface side resin layer 132 of water level sensor 100 concerning an embodiment of the present invention. It is a figure explaining an example of installation of water level detection system 1 concerning an embodiment of the present invention. It is a figure explaining water level detection by water level sensor 100 concerning an embodiment of the present invention. It is a figure explaining water level detection by water level sensor 100 concerning an embodiment of the present invention. It is a figure showing an example of transition of the 1st reference electrode capacitance value ( _Cr1 ). It is a figure showing an example of transition of the 1st reference electrode capacitance value ( _Cr1 ). It is a figure showing a flow chart of a data processing algorithm of water level detection system 1 concerning an embodiment of the present invention. It is a figure explaining water level detection by water level sensor 100 concerning an embodiment of the present invention. FIG. 9 is a diagram illustrating a configuration example of data transmitted from a data communication unit 187. It is a figure showing an example of transition of the 1st reference electrode capacitance value ( _Cr1 ). FIG. 5 is a diagram showing water level detection using the water level sensor 100 in multiple stages. FIG. 3 is a diagram illustrating an equivalent circuit of a water level detection electrode pair 110.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a schematic configuration of a water level detection system 1 according to the embodiment of the present invention, and FIG. 2 is a block diagram of the water level detection system 1 according to the embodiment of the present invention.

  The water level detection system 1 according to the present invention includes a water level sensor 100, which is a sensor part that contacts rainwater or the like and detects the water level, a flat cable 160 connected to the water level sensor 100 via a first connector 151, It has a flat cable 160 and a control box 170 connected via the second connector 172. The flat cable 160 is a cable having a predetermined length for electrically stably connecting the water level sensor 100 and the control box 170. The control box 170 includes components other than those surrounded by the dotted line indicated by 100 in FIG.

  The water level sensor 100 is of a capacitance type, and detects a water level of rainwater or the like that comes into contact with the water level sensor 100. However, the water level sensor 100 does not directly detect the water level. The water level sensor 100 includes a water level detection electrode pair 110 that detects a capacitance value used for calculating a water level, and a first reference that detects a capacitance value that is referred to for calibration when calculating the water level. The electrode pair 111 and the second reference electrode pair 112 have a structure sealed between two resin layers.

  FIG. 3 is a diagram illustrating the arrangement of the electrodes of the water level sensor 100 according to the embodiment of the present invention. This figure is a diagram in which electrodes are arranged on an outer shape of a resin layer used for sealing. Each of the following electrode pairs is parallel to each other and has the same width (length in a direction orthogonal to the longitudinal direction in the plane of the paper). In addition, a capacitor is formed between the pair of electrodes. One electrode of the electrode pair is used as a capacitance measurement electrode, and the other electrode is used as a drive electrode.

  The capacitance of the capacitance element formed between the electrode pair is determined by the surface area of the measurement electrode and the drive electrode (electrode pair), the distance between the electrodes, and the dielectric constant. The permittivity of the liquid (water) is sufficiently larger than the permittivity of air. Therefore, the capacitance between the measurement electrode and the drive electrode is substantially proportional to the surface area immersed in the liquid surface, that is, the length from the lower end of each electrode pair to the liquid surface level.

  The water level detection electrode pair 110 of the water level sensor 100 according to the present invention has a longitudinal direction, and it is assumed that the water level sensor 100 uses this longitudinal direction parallel to the vertical direction. Thereby, the capacitance value based on the water level rising from the lower end portion 102 to the upper end portion 103 of the water level sensor 100 is obtained.

Assuming the z coordinate along this longitudinal direction, the lower end of the water level detection electrode pair 110 is set to z = 0 cm. In the present embodiment, the upper end of the water level detection electrode pair 110 is z = 25 cm. That is, the length of the water level detection electrode pair 110 is set to 25 cm. The length of the water level detection electrode pair 110 is not limited to this, but is a practically suitable length for measuring the water level due to flooding of the road.

  The first reference electrode pair 111 has a lower end at the same height as the lower end of the water level detection electrode pair 110, and has a configuration shorter than the length of the water level detection electrode pair 110. In the present embodiment, the lower end of the first reference electrode pair 111 is z = 0 cm, and the upper end is z = 1 cm. That is, the length of the first reference electrode pair 111 is set to 1 cm.

  However, the length of the first reference electrode pair 111 is not limited to this. Setting the width of the water level detection electrode pair 110 and the width of the first reference electrode pair 111 to be equal is more preferable because the calculation of the water level based on the capacitance value is simpler, but is not essential.

  The second reference electrode pair 112 has a lower end at the same height as the upper end of the water level detection electrode pair 110. In the present embodiment, the lower end of the second reference electrode pair 112 is z = 25 cm, and the upper end is z = 26 cm. That is, the length of the second reference electrode pair 112 is set to 1 cm. The length of the second reference electrode pair 112 is set equal to the length of the first reference electrode pair 111.

  Further, since the width of the first reference electrode pair 111 is equal to the width of the second reference electrode pair 112, the capacitance value detected by the first reference electrode pair 111 and the capacitance value detected by the second reference electrode pair 112 are detected. The capacitance value can be treated in the same manner. The length of the second reference electrode pair 112 is not limited to 1 cm.

  The conductive line 115 is provided for each of the water level detection electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112. These conductive lines 115 guide the conductive portion from each electrode pair to the conductive line leading end 105. At the conductive line leading end 105, each conductive line 115 is electrically connected to a conductive part (not shown) of the first connector 151.

  Each electrode pair and the conductive line 115 can be formed by, for example, partially etching a conductive material in a resin layer to which a conductive material such as copper is attached.

  FIG. 4 is a diagram showing a cross-sectional structure of the water level sensor 100. More specifically, FIG. 4 is a diagram showing a cross section of a portion corresponding to X-X ′ in FIG. 3 in the water level sensor 100.

  The water level detection electrode pair 110 and the conductive line 115 are provided on one main surface of the base resin layer 134. The ground electrode 120 is provided on the other main surface of the base resin layer 134. This ground electrode 120 is shown by a dotted line in FIG. Since such a ground electrode 120 is provided, in the water level sensor 100, only the capacitance based on water contacting one main surface needs to be considered.

  As described above, the base resin layer 134 in which the water level detection electrode pair 110 and the conductive line 115 are provided on one main surface and the ground electrode 120 is provided on the other main surface is a back side resin layer provided with a hot melt layer. Each electrode pair and the conductive line 115 are sealed by being sandwiched by the 131 and the surface side resin layer 132 and heated and pressed. The layer formed by melting the hot melt layer is referred to as a fusion resin layer 135.

  For the back side resin layer 131, the front side resin layer 132, and the base resin layer 134, for example, an insulating member having a low water absorption such as polyethylene terephthalate (PET), polyester, nylon, or liquid crystal polymer can be used.

  The surface side resin layer 132 functions as a sensing surface for measuring a water level in the water level sensor 100 according to the present invention, but may have other functions. FIG. 5 is a diagram illustrating an example of use of the surface-side resin layer 132 of the water level sensor 100 according to the embodiment of the present invention. FIG. 5 shows an example in which public information is used by printing “evacuation site at disaster ○ △ □ elementary school” on the front side resin layer 132. For example, it is assumed that the water level sensor 100 is used by being attached to a utility pole or the like. In such a case, the space of the surface-side resin layer 132 can be effectively used for publicity.

  As described above, it is assumed that the water level sensor 100 according to the present invention is mounted on an existing pillar-shaped structure such as a utility pole in a city. To this end, an adhesive layer 140 is provided on the back side resin layer 131 side. FIG. 6 is a diagram illustrating an installation example of the water level detection system 1 according to the embodiment of the present invention. The water level sensor 100 is attached to the lower side of a structure such as a utility pole using the adhesive layer 140. On the other hand, the control box 170 connected to the water level sensor 100 via the flat cable 160 is attached to the upper side of a structure such as a telephone pole by, for example, a fastening band 175 or the like.

  According to the water level sensor 100 according to the present invention as described above, it is possible to manufacture the sensor at low cost. Further, the water level detection system 1 using such an inexpensive water level sensor 100 can be installed and operated on a plurality of roads where flooding is likely to occur.

  Further, according to the water level sensor 100 according to the present invention, it is possible to easily install the water level sensor 100 by simply attaching the water level sensor 100 to a utility pole or the like with the adhesive layer 140.

  Further, according to the water level sensor 100 according to the present invention, the front side resin layer 132 can be used for publicity and the like.

  The details of the control box 170 connected to the water level sensor 100 according to the present invention configured as described above will be described with reference to the block diagram of FIG.

  In FIG. 2, a main control unit 180 is, for example, a microcomputer or the like, and transmits a control command, receives data, and executes arithmetic processing to each connected component. The main control unit 180 can transmit a control signal of an on / off command to at least the electrode drive circuit 185 and the data communication unit 187.

  The electrode drive circuit 185 applies a predetermined voltage (also referred to as a “drive signal”) to one of the drive electrodes of the water level detection electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112. It is. The electrode drive circuit 185 can selectively apply such a drive signal to each electrode pair. That is, the electrode drive circuit 185 applies a drive signal only to the first reference electrode pair 111, for example, and stops applying drive signals to the water level detection electrode pair 110 and the second reference electrode pair 112, or detects the water level. A drive signal can be applied to all of the electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112.

  The main control unit 180 detects capacitance data detected by the water level detection electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112 and digitized by an AD conversion circuit (not shown) (each of which is “water level electrode static Capacitance value, "first reference electrode capacitance value," and "second reference electrode capacitance value." The main control unit 180 stores the received capacitance data in the data storage unit 186 which is a nonvolatile storage element.

The data communication section 187 can transmit and receive data wirelessly, and is controlled by the main control section 180. The data communication unit 187 can use WWAN. In the water level detection system 1 according to the present invention, it is assumed that the data communication unit 187 mainly transmits the capacitance data detected by the electrode pair to information collection means such as a server (not shown). The server calculates the water level at each location where the water level detection system 1 is installed, based on the received capacitance data.

  The battery 183 supplies power to the main control unit 180, the electrode drive circuit 185, the data storage unit 186, and the data communication unit 187. In the water level detection system 1 according to the present invention, by providing such a battery 183, it is possible to install the battery 183 in a place where a commercial power supply cannot be used. On the other hand, adoption of the battery 183 requires maintenance such as replacement work. Since it is preferable to reduce the frequency of such maintenance work as much as possible, the water level detection system 1 according to the present invention employs a control process that saves the capacity of the battery 183 as much as possible.

  Next, data processing of the water level detection system 1 configured as described above will be described. FIG. 7 and FIG. 8 are diagrams illustrating water level detection by the water level sensor 100 according to the embodiment of the present invention. The figure schematically shows a water level sensor 100 installed for measuring a water level due to rainwater.

  7 and 8, the water level detection electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112 in the water level sensor 100 are shown transparently.

  FIG. 7 shows a state in which no rainwater exists when there is no rainfall. In the water level detection system 1 according to the present invention, in order to save the capacity of the battery 183, only the first reference electrode pair 111 is driven during non-rainfall to monitor the capacitance. . That is, during a non-rainfall period, the water level detection electrode pair 110 and the second reference electrode pair 112 are not driven, and their capacitances are not acquired.

FIG. 9 shows an example of transition of the first reference electrode capacitance value in the state shown in FIG. In figures such as FIG. 9, the horizontal axis indicates time, and the vertical axis indicates the first reference electrode capacitance value in pF. Here, mark the first reference electrode capacitance value C _r1. As shown in FIG. 9, when no rainfall occurs, the first reference electrode capacitance value C _r1 takes a substantially constant value.

FIG. 8 shows a state where rainfall has started and rainwater has started to collect, and a predetermined water level is being formed. FIG. 10 shows an example of transition of the first reference electrode capacitance value (C _r1 ) in such a state.

When the water level approaches the lower end of the first reference electrode pair 111 at the timing (A) in the figure with the rise of the water level of the rainwater, the value of the first reference electrode capacitance value (C _r1 ) gradually increases. Go.

As the water level further rises, the water level passes through the upper end of the first reference electrode pair 111 and the first reference electrode pair 111 is completely submerged. The value of the capacitance value (C _r1 ) hardly fluctuates.

In the water level detection system 1 according to the present invention, the timing at which the first reference electrode pair 111 is completely submerged (B) is detected. Then, when this is detected, acquisition of capacitance data by the water level detection electrode pair 110 and the second reference electrode pair 112 is started, and data transmission from the data communication unit 187 is started accordingly. As described above, in the water level detection system 1 according to the present invention, since all the functions necessary for detecting and transmitting the water level are executed at the timing after the first reference electrode pair 111 is completely submerged, the battery 183 can be saved.

  In the water level detection system 1, the power consumption ratio of the data communication unit 187 is particularly high, and the capacity of the battery 183 is effectively reduced by basically stopping the data communication unit 187 during non-rainfall. Can be saved.

  Next, an example of data processing for detecting the timing (B) as described above will be described. FIG. 11 is a diagram illustrating a flowchart of a data processing algorithm of the water level detection system 1 according to the embodiment of the present invention. Such a flowchart is executed by the main control unit 180.

  Data processing is started in step S100. The start of such data processing is, for example, immediately after the replacement of the battery 183.

In step S101, the first reference electrode capacitance value (C _r1 ) is obtained from the first reference electrode pair 111, and in step S102, this is stored in the data storage unit 186.

Subsequently, in step S103, the data storage unit 186 based on the stored capacitance value into _{Avg1 (C r1), Avg2 (} C r1), and calculates the Avg3 (C _r1).

Avg1 (C _r1 ) is the average value of the first reference electrode capacitance value (C _r1 ) from the current time to T ₁ hours before, and Avg2 (C _r1 ) is Tg from the current time. The average value of the first reference electrode capacitance value (C _r1 ) up to _two hours before, and Avg3 (C _r1 ) is the first reference electrode capacitance value from the current time to before the T ₃ incident. This is the average value of the capacitance value (C _r1 ). Here, T ₁ <T ₂ <T ₃ . (Refer to FIG. 9 and FIG. 10 for approximate times of T ₁ , T ₂ , and T _3. )
Subsequently, in step S104,
_{| Avg1 (C r1) -Avg2 (} C r1) | <δ
And _{Avg1 (C r1) -Avg3 (C} r1)> ΔC
Is determined.

Here, [delta] is a small value, the value of Avg1 (C _r1) is also a value used to confirm that almost no difference also values Avg2 (C _r1).

_{| Avg1 (C r1) -Avg2 (} C r1) | If <[delta] is satisfied, the value of Avg1 (C _r1), which means that almost no difference also values Avg2 (C _r1).

ΔC is a predetermined constant, and is a value for determining that the first reference electrode pair 111 is completely submerged in view of the value of the difference between Avg1 (C _r1 ) and Avg3 (C _r1 ). The value of ΔC can be changed by setting the time lengths of T ₁ , T ₂ and T ₃ , and an image of the value of ΔC is shown in FIG.
Avg1 If _{(C r1) -Avg3 (C r1} )> ΔC is satisfied, which means that there is more than a predetermined increase in the first reference electrode capacitance value (C _r1).

As shown in FIG. 9, when the first reference electrode capacitance value (C _r1 ) is changing, the determination in step S104 is NO. If the determination in step S104 is NO, the process returns to step S101.

On the other hand, when the first reference electrode capacitance value (C _r1 ) is changing as shown in FIG. 10, the determination in step S104 is YES. In this case, the process proceeds to step S105, where the electrode driving circuit 185 for the water level detection electrode pair 110 is turned on, and the detection by the water level detection electrode pair 110 is started. Further, the process proceeds to step S106, where the electrode drive circuit 185 for the second reference electrode pair 112 is turned on, and the detection by the second reference electrode pair 112 is started.

In the next step S107, the first reference electrode pair 111 to the first reference electrode capacitance value (C _r1 ), the water level detection electrode pair 110 to the water level detection electrode capacitance value (referred to as C ₀ ), and the second reference electrode The second reference electrode capacitance value (referred to as _Cr2 ) is acquired from the pair 112, and each of these data is transmitted to the server by the data communication unit 187 turned on.

The measurement of the capacitance value in step S107 assumes a situation as shown in FIG. 12 after the first reference electrode pair 111 is submerged. In such a situation, the water level detection electrode pair 110 has a submerged portion having a length (x) and a non-submerged portion having a length (25-x). ₀ ) is output. At this time, the server uses the first reference electrode capacitance value (C _r1 ) to calibrate x of the submerged portion, and uses the second reference electrode capacitance (C _r1 ) to calibrate (25-x) of the non-submerged portion. The reference electrode capacitance value (C _r2 ) is used to calculate x relating to the water level.

In addition, under rainfall, it is assumed that raindrops are attached to the non-submerged portion of the water level detection electrode pair 110, and the same applies to the second reference electrode pair 112. The second reference electrode capacitance value (C _r2 ) by the electrode pair 112 can be used for such a calibration.

Here, in the water level detection system 1 according to the present invention, the water level detection electrode capacitance value (C ₀ )
The principle of calculating x relating to the water level using the first reference electrode capacitance value (C _r1 ) and the second reference electrode capacitance value (C _r2 ) will be described. FIG. 16 is a diagram illustrating an equivalent circuit of the water level detection electrode pair 110.

The capacitance of the portion x where the water level detection electrode pair 110 is submerged is C ₁ , and the water level detection electrode pair 1 is
10 is not submerged portion capacitance of (25-x) When C _2, the water level detecting electrode capacitance value C _0, it regarded as the capacitance C ₁ and the capacitance C ₂ connected in parallel So you can
C ₀ = C ₁ + C ₂ (1)
The measured water level detection electrode capacitance value C ₀ is a function C ₀ = C ₀ (x) of x, and this C ₀ (x) is
ε ₁ : dielectric constant between electrodes per unit length [cm] of submerged part ε ₂ : dielectric constant between electrodes per unit length [cm] of non-submerged part
C ₀ (x) == ε ₁ x + ε ₂ (25−x) (2)
Holds.

The permittivity _{1 1} can be obtained based on the first reference electrode capacitance value (C _r1 ), the permittivity _{2 2} can be obtained based on the second reference electrode capacitance value (C _r2 ), Furthermore, since C ₀ (x) can be measured, the length x of the submerged portion of the water level detection electrode pair 110 can be calculated by solving (2).

In the present embodiment, the second reference electrode pair 112 is provided to measure the second reference electrode capacitance value C _r2 , and the permittivity ε ₂ is calculated based on the measured value. It is considered that the pair 112 is basically only exposed in the air, and if the dielectric constant ε ₂ is constant, the second reference electrode pair 112 can be omitted. In the present invention, such an embodiment in which the second reference electrode pair 112 is omitted is also included in the category.

  The dielectric constant (relative dielectric constant) is a basic electrical constant of a medium irrespective of gas, liquid, or solid.

The dielectric constant ε in a vacuum state is 1.0. In the case of air, ε ₂ ≒ 1.0, and in the case of water, ε ₁ ≒ 80.4 (20 ° C.).

  Therefore, since the dielectric constant of the submerged part and the non-submerged part is different by about 80 times, it is possible to measure the water level by changing the dielectric constant through the capacitance measurement.

On the other hand, since the permittivity of water changes depending on the temperature, some corrective means is required to accurately measure the water level. In this embodiment, ε ₁ is corrected using the first reference electrode. However, the correction of the dielectric constant ε _{2 in} the case of air can be omitted because the temperature dependency is small.

  However, according to the embodiment in which the second reference electrode pair 112 is provided, there is an advantage that it is possible to acquire information on whether or not it is raining, in addition to information on the flooded water level.

In step S107, a process of transmitting the acquired capacitance value (capacitance data) from the data communication unit 187 to the server side is further executed. At this time, data to be transmitted will be described. Figure 13 is a diagram showing a structural example of the data D ₀ to be transmitted from the data communication unit 187.

Data D ₀ transmitted from data communication unit 187 includes data D ₁ “own device ID data (XXXXX)”. For each of the water level detection system 1, and only one ID has been shaken, the ID is described in the data D _1. This allows the server to know at which location the information is transmitted from the water level detection system 1 installed.

The data D ₀ transmitted from the data communication unit 187 includes data D ₂ “date data (yyyy / mm / dd)” and data D ₃ “time data (hh: mm: ss)”. . In step S107, the frequency of acquiring data from the water level detection electrode pair 110, the first reference electrode pair 111, and the second reference electrode pair 112 can be, for example, about once per minute. For this, the data transmitted from the data communication unit 187, includes such date data D ₂ h data D _3.

The data D ₀ transmitted from the data communication unit 187 includes data D ₄ “first reference electrode capacitance data (C _r1 )” and data D ₅ “water level detection electrode capacitance data (C ₀ )”. , Data D ₆ "second reference electrode capacitance data (C _r2 )". Based on these data, the server can calculate the water level at the place where the water level detection system 1 is installed.

In step _{S108, | Avg1 (C r1)} -Avg2 (C r1) | < whether [delta] ₁ is determined. Here, δ ₁ is a minute value, and the value of Avg1 (C _r1 ) is also Avg1 (C _r1 ).
The value of 2 (C _r1 ) is also a value used to confirm that there is almost no difference.

_{| Avg1 (C r1) -Avg2 (} C r1) | If <[delta] ₁ is satisfied, Avg1 (C _r1)
Means that there is almost no difference in the value of Avg2 (C _r1 ). In this step, it is determined whether the water level has decreased as shown in FIG. 14 and the first reference electrode pair 111 has not been submerged.

  If the decision result in the step S108 is NO, it means that the water level of the rainwater is not lowered, so the process returns to the step S107 and the measurement by all the electrode pairs is continued.

  On the other hand, if the decision result in the step S108 is YES, it means that the water level of the rainwater has dropped and the first reference electrode pair 111 has escaped from the submerged state. In this case, subsequently, the process proceeds to step S109, in which the detection by the water level detection electrode pair 110 and the second reference electrode pair 112 is stopped (that is, the drive voltage for the water level detection electrode pair 110 and the second reference electrode pair 112 by the electrode driving circuit 185). Is stopped), and the data transmission from the data communication unit 187 is also stopped.

  As described above, according to the water level detection system 1 of the present invention, when the water level is 0 during non-rainfall, power is not supplied to the electrode pairs that do not need to be detected, and the consumption of the capacity of the battery 183 is suppressed. And the frequency of maintenance work for replacing the battery 183 can be suppressed, and the probability that the water level information cannot be acquired when the capacity of the battery 183 is exhausted during rainfall can be suppressed. Become.

  Furthermore, according to the water level detection system 1 according to the present invention, the driving of the data communication unit 187, which consumes a large amount of battery capacity, can be limited to only during rainfall, and further reduction in capacity consumption of the battery 183 can be realized. .

  Note that the flowchart shown in FIG. 11 does not assume that the water level detection electrode pair 110 and the second reference electrode pair 112 will be submerged. However, when there is a possibility that the water level detection electrode pair 110 and the second reference electrode pair 112 are submerged, the transition of the capacitance data as shown in FIG. It is possible to grasp each submergence.

  Further, in a case where a rise in the water level of 25 cm or more is expected at the installation location of the water level detection system 1, the water level sensor 100 can be used in multiple stages. FIG. 15 is a diagram showing water level detection using the water level sensor 100 in multiple stages. That is, the height of the upper end of the water level detection electrode pair 110 in the water level sensor 100 provided on the lower side is equal to the height of the lower end of the water level detection electrode pair 110 'in the water level sensor 100' provided on the upper side. By arranging, it is possible to measure the water level of 25 cm or more.

DESCRIPTION OF SYMBOLS 1 ... Water level detection system 100 ... Water level sensor 102 ... Lower end part 103 ... Upper end part 105 ... Conductive line drawing end part 110 ... Water level detection electrode pair 111 ... First reference electrode Pair 112: Second reference electrode pair 115: Conductive line 120: Ground electrode 131: Back side resin layer 132: Front side resin layer 134: Base resin layer 135 ... Fused resin layer 140 Adhesive layer 151 First connector 160 Flat cable 170 Control box 172 Second connector 175 Fastening band 180 Main controller 183 ... Battery 185 ... Electrode drive circuit 186 ... Data storage unit 187 ... Data communication unit

Claims (4)

A water level detection electrode pair whose longitudinal direction is arranged vertically,
A first reference electrode pair having a lower end at the same height as the lower end of the water level detection electrode pair, and having a shorter length than the length of the water level detection electrode pair,
An electrode drive circuit for selectively amplifying after applying a drive signal to the water level detection electrode pair and the first reference electrode pair,
A data storage unit for storing a capacitance value between the electrode pair of the water level detection electrode pair and each of the first reference electrode pair,
A main control unit that outputs an on / off command to the electrode drive circuit,
The main control unit determines whether to apply a drive signal to the water level detection electrode pair based on a capacitance value of the first reference electrode pair stored in the data storage unit, and A water level detection system which outputs an on / off command to a circuit. Further comprising a data communication unit for transmitting a capacitance value between the electrode pair of the water level detection electrode pair and the first reference electrode pair,
The said main control part outputs an on / off command to the said data communication part based on the electrostatic capacitance value of the said 1st reference electrode pair memorize | stored in the said data storage part, The claim of Claim 1 characterized by the above-mentioned. Water level detection system. A second reference electrode pair having a lower end at the same height as the upper end of the water level detection electrode pair and having the same length as the first reference electrode pair,
The electrode drive circuit selectively applies a drive signal to the second reference electrode pair,
The data storage unit stores a capacitance value between the electrode pair of the second reference electrode pair,
The main control unit determines whether to apply a drive signal also to the second reference electrode pair based on the capacitance value of the first reference electrode pair stored in the data storage unit, The water level detection system according to claim 1, wherein an on / off command is output to the electrode drive circuit. A data communication unit that transmits a capacitance value between the electrode pair of the water level detection electrode pair, the first reference electrode pair, and the second reference electrode pair,
The said main control part outputs an on / off command to the said data communication part based on the electrostatic capacitance value of the said 1st reference electrode pair memorize | stored in the said data storage part, The claim of Claim 3 characterized by the above-mentioned. Water level detection system.

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