KR20210045794A - Water level detecting apparautus and system - Google Patents

Abstract

A water level sensing device according to an embodiment of the present invention comprises: a power supply unit; a control unit that generates a control signal of pulse power to be applied to the water and determines the water level based on a water level sensing signal; a pulse power generation unit generating the pulse power according to a control signal of the control unit; and a water level sensing unit that applies the pulse power to the water, generates a level sensing signal for the water and transmits the same to the control unit. The pulse power generation unit may include only a plurality of switching elements and a plurality of resistors, and may generate the pulse power through on/off control of the plurality of switching elements according to a control signal of the control unit.

Description

Water level detection device and system {WATER LEVEL DETECTING APPARAUTUS AND SYSTEM}

The present invention relates to a water level sensing device and system, in particular to a device and system for sensing the water level in a water tank of a boiler.

Conventionally, depressurized AC power is applied to detect the water level of the boiler water tank, and when the water level is high, the reduced AC power is conducted by water, and a photo coupler, a sensing circuit, is turned ON. ), and when the water level drops, the reduced AC power is not conducted by water, and the photo coupler is turned off.

However, this method always consumes a certain level of power because the power is always used for detecting the water level, and thus there is a problem that power is wasted.

In addition, conventionally, as a method of detecting the water level of a boiler water tank using a direct current (DC) power source, power is applied only when the direct current power is turned on/off and detected, and a pulse signal is generated in the current amplifying circuit. I did. In this case, in order to prevent corrosion of the electrode, a DC component was removed using a capacitor and a pulsed current was allowed to flow through the water.

However, this method has a problem in that it is difficult to detect immediately because the frequency of the applied pulse must be increased due to the capacitor for removing the DC component, and the capacitor must be charged for stabilization. In addition, since the water level in the water tank is sensed using the water level rod, standby power is generally consumed to some extent, it is difficult to react immediately to changes in the water level, and it is composed of a complex structure, so that the material cost is increased, and the reliability is low.

An object of the present invention is to provide a water level sensing device and system capable of quickly detecting the water level of a boiler water tank and minimizing standby power with only a simple configuration without limiting the frequency.

The water level detection device according to an embodiment of the present invention includes a power supply supplying power, a control unit that generates a control signal of pulse power to be applied to water, and determines the level of water based on the water level detection signal, and the control of the control unit. A pulse power generator for generating the pulsed power by a signal, and a water level detector for applying the pulsed power to the water, generating a water level detection signal for the water and transmitting it to the control unit, and generating the pulsed power The unit is composed of only a plurality of switching elements and a plurality of resistors, and the pulsed power may be generated through on/off control of the plurality of switching elements by a control signal from the control unit.

A method for detecting a water level according to an embodiment of the present invention, comprising: supplying, by a control unit of a water level detection device, to a pulse power generation circuit, which is provided separately from power applied to the control unit, during a detection period, and provided separately The pulsed power generation circuit may include generating a pulsed power based on the generated power, applying the pulsed power to water, and detecting a water level detection signal based on the pulsed power applied to the water. .

The water level detection circuit according to an embodiment of the present invention includes a power circuit provided separately from power supplied to the control unit, first to fourth resistors sequentially connected in series between one end and the other end of the power circuit, and the first resistor. A first switching element connected between a node between and a second resistor and a second switching element, a node between the third resistor and a fourth resistor, and the second switching element connected between the first switching element, And a detection circuit connected between a node between the first switching element and the second switching element and a node between the second resistor and the third resistor, wherein the detection circuit comprises the first switching element and the first switching element. 2 When pulse power generated through on/off control of a switching element is applied to water, a water level detection signal may be transmitted to the controller.

A water level detection system according to an embodiment of the present invention includes a water tank of a boiler storing water to be supplied to the boiler, a water level detection device for detecting a level of water contained in the water tank of the boiler, and sensing the water level. The apparatus includes: a power supply supplying power, a control unit for generating a control signal of a pulsed power applied to the water tank of the boiler, and determining the water level based on a water level detection signal, and the pulse by the control signal of the control unit. A pulse power generator for generating power, and a water level detector for applying the pulsed power to the water tank of the boiler and generating a water level detection signal for the water tank of the boiler and transmitting it to the control unit, and the pulse power The generator is composed of only a plurality of switching elements and a plurality of resistors, and may generate the pulsed power through on/off control of the plurality of switching elements by a control signal from the controller.

According to the water level sensing device and system of the present invention, it is possible to quickly detect the water level of a boiler water tank with only a simple configuration without limiting the frequency, and to minimize standby power.

1 is a block diagram of a water level sensing device according to an embodiment of the present invention.
2 is a circuit diagram of a water level sensing device according to an embodiment of the present invention.
3 is a simplified diagram illustrating the circuit diagram of FIG. 2.
FIG. 4A is a diagram illustrating switching control so that a (+) pulse power is applied to water, and FIG. 4B is a diagram illustrating switching control so that a (-) pulse power is applied to water.
5 is a diagram showing a voltage waveform according to a conventional water level detection method.
6A is a diagram illustrating a voltage waveform and a water level detection waveform applied to water in a water level detection device according to an embodiment of the present invention.
6B is a diagram illustrating a control waveform of an MCU of a water level sensing device according to an embodiment of the present invention.
7 is a diagram showing an average power (top) and a power waveform (bottom) of the water level sensing device according to an embodiment of the present invention.
8 is a flowchart illustrating a method of detecting a water level according to an embodiment of the present invention.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In this document, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

For the various embodiments of the present invention disclosed in this document, specific structural or functional descriptions have been exemplified only for the purpose of describing the embodiments of the present invention, and various embodiments of the present invention may be implemented in various forms. And should not be construed as being limited to the embodiments described in this document.

Expressions such as "first", "second", "first", or "second" used in various embodiments may modify various elements regardless of their order and/or importance, and the corresponding elements Not limited. For example, without departing from the scope of the present invention, a first component may be referred to as a second component, and similarly, a second component may be renamed to a first component.

Terms used in this document are only used to describe a specific embodiment, and may not be intended to limit the scope of other embodiments. Singular expressions may include plural expressions unless the context clearly indicates otherwise.

All terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art. Terms defined in a commonly used dictionary may be interpreted as having the same or similar meaning as the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this document. . In some cases, even terms defined in this document cannot be interpreted to exclude embodiments of the present invention.

1 is a block diagram of a water level sensing device according to an embodiment of the present invention.

Referring to FIG. 1, a water level detection device 100 according to an embodiment of the present invention may include a power supply unit 110, a control unit 120, a pulse power generation unit 130, and a water level detection unit 140. For example, the water level sensing device 100 according to an embodiment of the present invention may be used to detect the water level of a water tank of a boiler.

The power supply unit 110 may supply power to the pulse power generation unit 130. The power supply unit 110 may be a power source provided separately from power supplied to the control unit 120.

The controller 120 may generate a control signal for generating a pulsed power applied to the water, and may determine the water level based on the water level detection signal received from the water level detection unit 140. That is, the controller 120 may generate a control waveform for causing the pulse power generator 130 to generate a pulse power, and the control waveform may be a plurality of pulse waveforms. For example, the control unit 120 may function as a main control unit (MCU) of a water level detection circuit.

That is, when pulse power is applied to water from the pulse power generation unit 130, the water level detection unit 140 generates a water level detection signal for the water level and transmits it to the control unit 120. Accordingly, the control unit 120 may determine the level of water based on the level detection signal.

The pulsed power generator 130 may generate pulsed power for applying to water by a control signal from the controller 120. In this case, the pulse power generation unit 130 includes a plurality of switching elements and resistors, and may generate pulse power through on/off control of the plurality of switching elements by a control signal from the controller 120. For example, the switching element may be a photo coupler. In other words, the pulse power generation unit 130 may not include a capacitor unlike the conventional one.

In the case of the conventional water level detection circuit, since a method of removing a direct current (DC) component of a pulse signal using a capacitor is used, a pulse signal having a high frequency is required, so there is a problem that noise is generated. In addition, since it was necessary to secure the charging time of the capacitor, immediate detection was inevitably difficult.

On the other hand, the water level detection device 100 according to an embodiment of the present invention generates a pulse power by removing a direct current (DC) component from the pulse power generator 130 consisting of a resistor and a switching element, thereby detecting the water level without a capacitor. As a result, it is not limited by frequency and can quickly detect the water level without the need for charging time, so that power can be used efficiently.

In addition, a plurality of resistors of the pulse power generation unit 130 may be configured to be symmetric with respect to each of the plurality of switching elements. That is, a plurality of resistances based on the switching element of the pulse power generation unit 130 may be structurally symmetric and may be configured to have the same resistance value. This is to generate a voltage of the same magnitude in which the polarity is opposite in the pulse power generation unit 130, as described later.

The pulse power generator 130 may change the polarity of the pulse power through on/off control of a plurality of switching elements. Through this, the pulse power generator may generate a pulse power from which a direct current (DC) component is removed without a capacitor. For example, the pulse power generation unit 130 may be an H-bridge circuit.

Meanwhile, the pulse power generation unit 130 may adjust the pulse width and interval of the pulse power. For example, a user can generate pulse power by setting a desired pulse width and interval by a separate input unit (not shown). This is because the pulse power generation unit 130 of the water level sensing apparatus 100 according to an embodiment of the present invention does not include a capacitor unlike the prior art, and thus is not limited by the frequency of the applied pulse power.

The water level detection unit 140 may apply pulse power from the pulse power generation unit 130 to water, generate a water level detection signal for water, and transmit it to the control unit 120. For example, the water level detection unit 140 may include a plurality of detection sensors having different lengths. Therefore, it is possible to determine the water level according to whether an electric current passes through each sensor. However, the present invention is not limited thereto, and various types of sensors may be used, such as detecting the water level by disposing a plurality of sensors at regular intervals according to the height of the water tank.

As described above, according to the water level detection apparatus 100 according to an embodiment of the present invention, it is possible to quickly detect the water level with only a simple configuration without limiting the frequency, and to minimize standby power.

Meanwhile, although not shown in FIG. 1, the water level sensing device 100 according to an embodiment of the present invention may be connected to a water tank (not shown) of a boiler to detect the level of water contained in the water tank of the boiler. In this case, the water level detection unit 140 of the water level detection device 100 may be provided inside the boiler water tank.

2 is a circuit diagram of a water level sensing device according to an embodiment of the present invention.

Referring to FIG. 2, the water level detection device 200 according to an embodiment of the present invention includes a power supply unit 210, a power control unit 215, a control unit (MCU) 220, a pulse power generation unit 230, and a water level detection unit. It may include 240 and a water level sensor 250 and a plurality of resistors (R2 to R10).

The power supply unit 210 may supply power to the pulse power generation unit 230. Referring to FIG. 2, the power supply unit 210 may be a DC power supply of 24V. For example, the power supply unit 210 may correspond to the power supply unit 110 of FIG. 1.

The power control unit 215 includes a switching element U1 and is connected between the other components of the water level detection device 200 and the power supply unit 210 to control power on/off to control the power applied to the water level detection circuit. have.

The control unit (MCU) 220 may generate a control signal of pulsed power applied to water and determine the water level based on the level detection signal. Referring to FIG. 2, the control unit 220 may include signal generation units of V3, V4 and V5 that generate control signals for operating the pulse power generation unit 230. However, the present invention is not limited thereto, and the controller 220 may include any number of signal generators. For example, the control unit 220 may correspond to the control unit 120 of FIG. 1.

The pulse power generation unit 230 may generate pulse power based on a control signal generated by the signal generation units V3, V4, and V5 of the control unit 220. In this case, the pulse power generation unit 130 includes a plurality of switching elements and a plurality of resistors, and may generate pulse power through on/off control of the plurality of switching elements by a control signal from the control unit 120. . For example, the pulse power generation unit 230 may correspond to the pulse power generation unit 130 of FIG. 1.

2, the pulse power generation unit 230 includes a plurality of switching elements U2, U4, and resistors R7, R8, and a plurality of control signals from the signal generation units V3, V4 and V5 of the control unit 220 Pulse power can be generated through on/off control of the switching element of. As described above, since the pulse power generator according to an embodiment of the present invention is composed of only a plurality of switching elements U2 and U4 and resistors R7 and R8 without a capacitor, it is possible to immediately generate a pulse power without limitation of a pulse width or interval.

When the pulse power is applied by the pulse power generator 230, the water level detection unit 240 may be turned on/off according to the presence or absence of water, thereby generating a water level detection signal (waveform). The water level detection signal generated by the water level detection unit 240 may be transmitted to the control unit 220 again to determine the water level. For example, the water level detection unit 240 may correspond to the water level detection unit 140 of FIG. 1.

A plurality of water level detection sensors 250 may be provided to measure the level of water contained in the water tank. In this case, the water level sensor 250 may be in the form of a plurality of sensing rods having different lengths or in the form of a plurality of sensors disposed at each height in the water tank, but is not limited thereto and may be configured in various forms. That is, the water level detection sensor 250 may be used in any configuration as long as it is a configuration capable of determining the water level according to whether a current passes through contact with water.

Referring to FIG. 2, water in the water tank may be represented by a resistance R11. That is, even in the case of water, since it generally exhibits a constant value of resistance, it is expressed as one resistance in the present invention.

Meanwhile, the plurality of resistors R2 to R10 may be arbitrarily set according to the operation of the water level sensing device 200 according to an embodiment of the present invention, and are not limited to the values shown in FIG. 2. However, in the water level sensing device 200 according to an embodiment of the present invention, it is preferable that the resistances R2 to R10 are symmetrical in size and arrangement with respect to the plurality of switching elements U1 to U4.

That is, since the water level sensing device 200 according to an embodiment of the present invention generates a voltage of the same magnitude with opposite polarities through switching of a plurality of switching elements U1 to U4, even if the flow of current is different, It is necessary to have a symmetrical structure so that voltages of the same magnitude of opposite polarity are applied.

For reference, “COM” between R4 and R6 in FIG. 2 and “COM” between D2 and U4 denote a common node. In addition, a node displayed between R5 and R6 and a node displayed between R10 and R11 also represent a common node. Accordingly, as will be described later in FIG. 3, an equivalent circuit to which a common node is connected may be represented.

3 is a simplified diagram illustrating the circuit diagram of FIG. 2.

Referring to FIG. 3, a circuit diagram of the water level sensing device 200 of FIG. 2 may be represented by a power supply V2, a plurality of switching elements U1 to U4, and a plurality of resistors R3 to R6 and R9. Specifically, the water level detection device circuit includes a power supply V2 provided separately from the power supply to the control unit, resistors R3 to R6 (first to fourth resistors) sequentially connected in series between one end and the other end of the power circuit V2, and resistor R3. The node between the (first resistor) and the resistor R5 (the second resistor), the switching element U2 (first switching element), the resistor R6 (third resistor) and the resistor connected between the switching element U4 (the second switching element) Switching element U4 (second switching element) and switching element U2 (first switching element) and switching element U4 (second switching element) connected between the node between R4 (fourth resistor) and switching element U2 (first switching element) Switching element) and a detection circuit U3 connected between the node between the resistor R2 (second resistor) and the resistor R6 (third resistor). In this case, the detection circuit U3 can transmit a water level detection signal to the control unit when the pulse power generated through the on/off control of the switching element U2 (first switching element) and the switching element U4 (second switching element) is applied to the water. have.

As described above, according to the on/off control of the plurality of switching elements U1, U2, and U4 (310, 320, 330), the water level sensing device according to an embodiment of the present invention generates a voltage signal of the same size with opposite polarities. Since it must be created, resistors R5 and R6 must have a symmetrical structure and have the same value.

Further, the resistors R3 and R4 are resistors for preventing the power supply V2 of 24V from being short-circuited due to malfunction of the switching elements U2 and U4. As described above, the detection circuit U3 340 may function as a detection circuit for measuring the level of the water 350 in the water tank.

일 때, 저항 R5 및 R6을 가변시키는 경우 감지 회로 U3(340)의 출력이 0.7V(즉, MCU의 인식 전압) 이하가 되는 가장 큰 값은 13k

이 된다.In general, the resistors R3 to R6 and R9 may be arbitrarily set according to the operation of the water level sensing device 200. For example, if we first examine the case of R3 and R4 = 0 to select the range of resistances R5 and R6, the resistance of the water 350 included in the water tank is 50k.

When, when the resistors R5 and R6 are varied, the largest value at which the output of the sensing circuit U3 340 becomes 0.7V (i.e., the recognition voltage of the MCU) is 13k.

Becomes.

이하의 범위 중에서 작은 값을 선정하여도 되나, 그 값이 작을수록 전류가 커지므로 소비 전력이 증가하게 된다. 도 3에서와 같이, 저항 R5 및 R6을 2.5k

로 선정한 경우, 저항 R3 및 R4의 값에 따라 감지 회로 U3(340)의 출력이 달라지는데, 감지 회로 U3(340)의 출력이 0.7V 이하가 되어 수위 검출 신호를 인식하려면 저항 R3 및 R4는 610

이하의 값이어야 한다.At this time, the values of resistors R5 and R6 are 13k

A small value may be selected from among the following ranges, but the smaller the value, the greater the current, so the power consumption increases. As in Fig. 3, the resistors R5 and R6 are 2.5k

When selected as, the output of the sensing circuit U3 (340) varies according to the values of the resistors R3 and R4. To recognize the water level detection signal because the output of the sensing circuit U3 (340) is 0.7V or less, the resistors R3 and R4 are 610.

It should be the following value.

However, the values shown in FIG. 3 are merely exemplary, and any value may be selected as long as the values satisfy the above-described conditions.

FIG. 4A is a diagram illustrating switching control so that a (+) pulse power is applied to water, and FIG. 4B is a diagram illustrating switching control so that a (-) pulse power is applied to water.

In general, when the water level sensing device 200 is in a standby state, a plurality of switching elements U1, U2, and U4 are turned off so that the voltage applied to the water becomes 0V.

If the switching elements U1 and U2 (410a, 420a) are turned on and the switching elements U4 (430a) are turned off, a current flows as shown in FIG. 4A, and a (+) pulse power is applied to the water.

On the other hand, when the switching elements U1 and U4 (410a, 430a) are turned on and the switching element U2 (420a) is turned off, a current flows as shown in FIG. 4B, and a negative pulse power is applied to the water.

As described above, according to the water level sensing device according to an embodiment of the present invention, since it is possible to generate pulse voltages having the same polarity opposite to each other by using only the resistance and the switching element without having a capacitor, the limitation of the pulse width and the interval Since the water level can be detected immediately without receiving it, power can be used efficiently.

5 is a diagram showing a voltage waveform according to a conventional water level detection method.

5, the voltage waveform 510 of the upper graph represents the square wave voltage generated by the MCU, and the voltage waveform 520 of the lower graph indicates that the voltage waveform 510 is water by a voltage step-down circuit including a capacitor. It is converted into a bidirectional pulse signal applied to.

According to the conventional water level detection circuit, the pulse power is turned on/off and the power is applied only at the time of detection to generate a pulse signal in the current amplifying circuit, and a DC component is removed using a capacitor. As can be seen from FIG. 5, the standby power can be reduced to a certain level, but the pulse applied by the capacitor for removing the DC component must contain a high frequency, and the charging time of the capacitor (for example, , Since a stabilization period of 0 to 100 ms in the lower graph of FIG. 5) is required, immediate detection is inevitable.

6A is a diagram illustrating a voltage waveform and a water level detection waveform applied to water in a water level detection device according to an embodiment of the present invention.

Referring to FIG. 6A, a voltage waveform 610 is a pulsed power generated by a pulsed power generating unit. That is, as shown in FIGS. 4A and 4B, it is shown that voltage waveforms of the same size with opposite polarities are generated through on/off control using a plurality of switching elements.

In addition, the voltage waveform 620 of FIG. 6A represents a waveform in which the voltage waveform 610 is applied to water and a detection signal by the applied voltage waveform 610 is detected by the detection circuit U3 of FIGS. 4A and 4B. In this case, the detected waveform may be a signal applied to the control unit from the node between U3 and R9 of FIGS. 4A and 4B. The detected waveform is a detection signal when a non-zero value is applied to the voltage waveform 610, and a voltage change occurs.

For example, the voltage waveform 620 of FIG. 6A may be 0V when water is detected, and 5V when water is not detected. However, the present invention is not limited thereto, and the voltage value may vary depending on the operation method of the sensing circuit U3.

6B is a diagram illustrating a control waveform of an MCU of a water level sensing device according to an embodiment of the present invention.

6B, a plurality of control waveforms 630, 640, and 650 are shown. As described above, this causes the pulse power generator to generate the pulse power by the controller (MCU), and each of the waveforms in FIG. 6B may be generated by the control signal generators V3, V4, and V5 of FIG. 2. .

7 is a diagram showing an average power (top) and a power waveform (bottom) of the water level sensing device according to an embodiment of the present invention.

Referring to FIG. 7, the power waveform 720 of the water level sensing device according to an embodiment of the present invention is shown in a form including a pulse waveform and a peak, and in this case, the pulse width and interval can be arbitrarily adjusted. . According to this power waveform 720, the average power 710 increases and then gradually decreases.

In general, power consumption can be minimized as the width of the pulse to be applied is narrower and the interval for applying the pulse is increased. Since the water level sensing device according to an embodiment of the present invention is composed of a resistor and a switching element instead of a capacitor, the width and interval of the pulse applied to the water can be arbitrarily adjusted.

이고, 커패시터의 충전 시간이 150ms이며, 1초 간격으로 수위를 감지한다고 가정하면, 최소한 20mW의 전력을 소비하여야 한다. 또한, 방전 시간을 고려하고, 감지 속도를 더욱 빠르게 하려면 전력을 추가로 더 소비해야 한다.For example, in a conventional water level sensing circuit, the resistance of water is 1k.

And, assuming that the capacitor charging time is 150ms and the water level is sensed at 1 second intervals, at least 20mW of power should be consumed. In addition, additional power needs to be consumed to account for the discharge time and to speed up the detection.

, 저항 R3 및 R4을 500

으로 하고, 1μs를 1개 펄스로 하여 수위를 감지한다면 132nW(기존 전력의 약 15만 분의 1)만으로도 수위 감지가 가능해진다.On the other hand, the water level sensing device according to the present invention can freely set the pulse width (frequency) and does not require a separate charge/discharge time. If, as shown in Figs. 4a and 4b, the resistors R5 and R6 are 2.5k

, Resistors R3 and R4 500

And, if the water level is sensed with 1 μs as one pulse, the water level can be detected with only 132 nW (about 150,000th of the existing power).

8 is a flowchart illustrating a method of detecting a water level according to an embodiment of the present invention. The water level detection method of FIG. 8 may be performed by a pulse power generation circuit that does not include a capacitive element (eg, a capacitor) as described above.

First, the control unit (MCU) of the water level detection device supplies power separately provided to the control unit during the detection period to the pulse power generation circuit. Then, in step S810, a control signal of pulse power applied to water is generated. In this case, as described above, the signal generator of the control unit may generate at least one control signal. In addition, the control signal may be in the form of a pulse waveform as described above.

Further, in step S820, pulse power according to the control signal of the controller may be generated based on the separately provided power. As described above, the pulse power may be generated through switching control of a pulse generator including a plurality of switching elements and resistors. In this case, it is possible to generate a pulse waveform from which a direct current (DC) component is removed without a separate capacitor. In addition, the pulse power of step S820 may be a signal having the same voltage with opposite polarity.

In step S830, the generated pulsed power may be applied to the water in the water tank. In this case, the voltage waveform 610 of FIG. 6A described above may be applied to water. Next, in step S840, as pulse power is applied to the water, a water level detection signal for the water level may be generated and transmitted to the controller. In this case, the water level detection signal may be the voltage waveform S620 of FIG. 6A.

In step S850, the water level may be determined based on the water level detection signal received by the controller. That is, the water level detection signal detected by the water level detection unit is transmitted to the control unit again, and the control unit may determine the water level based on the signal.

As described above, according to the water level detection method according to an embodiment of the present invention, it is possible to quickly detect the water level with only a simple configuration without limiting the frequency, and to minimize standby power.

In the above, even if all the constituent elements constituting the embodiments of the present invention have been described as being combined into one or operating in combination, the present invention is not necessarily limited to these embodiments. That is, within the scope of the object of the present invention, all the constituent elements may be selectively combined and operated in one or more.

In addition, terms such as "include", "consist of" or "have" described above mean that the corresponding component may be present unless otherwise stated, excluding other components. It should not be construed as being able to further include other components. All terms, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art, unless otherwise defined. Terms generally used, such as terms defined in the dictionary, should be interpreted as being consistent with the meaning of the context of the related technology, and are not interpreted as ideal or excessively formal meanings unless explicitly defined in the present invention.

The above description is merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains will be able to make various modifications and variations without departing from the essential characteristics of the present invention. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100, 200: water level detection device 110: power supply
120: control unit 130: pulse power generation unit
140: water level detection unit 210: power supply unit
215: power control unit 220: control unit
230: pulse power generation unit 240: water level detection unit
250: water level detection sensor
310, 410a, 410b: switching element U1
320, 420a, 420b: switching element U2
330, 430a, 430b: switching element U4
340, 440a, 440b: sensing circuit U3 350, 450a, 450b: water (resistance)

Claims (12)

A power supply for supplying power;
A control unit that generates a control signal of a pulse power applied to water and determines a level of the water based on the level detection signal;
A pulse power generation unit generating the pulse power according to a control signal of the control unit; And
And a water level detector for applying the pulsed power to the water, generating a water level detection signal for the water, and transmitting it to the control unit,
The pulse power generation unit is composed of only a plurality of switching elements and a plurality of resistors, the level sensing device for generating the pulsed power through on/off control of the plurality of switching elements by a control signal of the control unit. The method according to claim 1,
The water level sensing device configured so that the plurality of resistors are symmetric with respect to each of the plurality of switching elements. The method according to claim 1,
The pulse power generation unit is a water level sensing device for changing the polarity of the pulse power through on/off control of the plurality of switching elements. The method according to claim 1,
The pulse power generation unit is a water level sensing device capable of adjusting the pulse width and interval of the pulse power. The method according to claim 1,
The pulse power generation unit is a water level sensing device of an H-bridge circuit. The method according to claim 1,
The pulse power generation unit is a water level sensing device for generating a pulse power from which a direct current (DC) component is removed. The method according to claim 1,
The switching element is a water level sensing device that is a photo coupler. The method according to claim 1,
The water level detection unit includes a plurality of detection sensors having different lengths. As a water level detection method,
Supplying, by a control unit of the water level detection device, to a pulse power generation circuit, during a detection period, power provided separately from power applied to the control unit;
Generating a pulsed power by the pulsed power generating circuit based on the separately provided power;
Applying the pulsed power to water; And
And detecting a water level detection signal based on the pulsed power applied to the water. The method of claim 9,
Wherein the pulsed power generation circuit does not include a capacitive element. A power circuit provided separately from power supplied to the control unit;
First to fourth resistors sequentially connected in series between one end and the other end of the power circuit;
A first switching element connected between a node between the first resistor and the second resistor and a second switching element;
The second switching element connected between the node between the third resistor and the fourth resistor and the first switching element; And
And a detection circuit connected between a node between the first switching element and the second switching element and a node between the second resistor and the third resistor,
The detection circuit is a water level detection circuit for transmitting a water level detection signal to the control unit when the pulse power generated through on/off control of the first and second switching devices is applied to water. A water tank of the boiler storing water for supply to the boiler;
And a water level sensing device for sensing the level of water contained in the water tank of the boiler,
The water level detection device,
A power supply for supplying power;
A control unit for generating a control signal of pulse power applied to the water tank of the boiler and determining a level of the water based on the level detection signal;
A pulse power generation unit generating the pulse power according to a control signal of the control unit; And
And a water level detector for applying the pulsed power to the water tank of the boiler, generating a water level detection signal for the water tank of the boiler, and transmitting it to the control unit,
The pulse power generation unit comprises only a plurality of switching elements and a plurality of resistors, and generates the pulsed power through on/off control of the plurality of switching elements by a control signal from the control unit.

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