JPH0432353B2 - - Google Patents

Description

[Detailed description of the invention]

(Technical Field) The present invention relates to an ultrasonic snow detection device. (Background technology) A snow detection device using ultrasonic waves transmits ultrasonic waves to the snow surface on the roof, receives the reflected waves, and
The snow height is measured from the time required from wave transmission to wave reception, and a detection operation is performed when the snow height exceeds a predetermined value. Figure 17 shows a conceptual diagram of the installation state of this type of snow detection device, where 1 is the sensor section, ROOF
is the roof. Therefore, ultrasonic waves are transmitted by the sensor microphone M of the sensor section 1, and reflected waves are received.If the distance _L0 of the sensor microphone M from the roof surface is constant, The shorter the distance L to the snow surface S, the greater the amount of snow on the roof surface, and conversely, the longer the distance L, the less the amount of snow on the roof surface. Now, if L ₀ -L=H (H: snow height on the roof surface), then when L ₀ = L, H=0, and the snow height H is 0.
It means that. Here, the relationship between the snow height H of the snow detection device and the detection error δ is as follows. δ=L・α (α; error constant) L=L ₀ −H ∴δ=(L ₀ −H)・α Therefore, as the snow height H becomes smaller, the detection error δ of the snow detection device becomes larger. In the detection of the snow height by the conventional snow detection device, due to the above-mentioned detection error δ, the judgment as to the presence or absence of snowfall when the snow height H is several centimeters or less is unstable and ambiguous. That is, the minimum snow height H at which it could be determined whether there was snow was 5 to 6 cm. Although it is theoretically possible to detect minute snow heights with a very precise configuration, it would be too expensive to use as a snow detection device for this type of snow melting, making it impossible to implement. be. By the way, some kind of snow melting equipment, such as underground water,
With snow melting equipment that pumps up seawater, etc. and releases it through a snow melting pipe to melt snow on roofs and roads, when snow has piled up evenly on the roof (several millimeters of snow)
It is necessary to activate the snow removal pump and melt the snow before it accumulates on the roof. Therefore, the above-mentioned detection of a snow height of 5 to 6 cm has the disadvantage that the timing of snow melting is delayed, making it difficult to melt the snow. (Object of the Invention) The present invention has been proposed in view of the above points, and its purpose is to perform a normal operation of outputting a signal when a predetermined snow height is exceeded, as well as to prevent the snow from falling evenly. An object of the present invention is to provide an ultrasonic snow detection device that can detect even accumulated snow (5 to 10 mm) and is compatible with two types of snow melting means. (Disclosure of the Invention) The present invention will be described in detail below with reference to the drawings showing embodiments. Fig. 1 is a block configuration diagram showing an embodiment of the ultrasonic snow detection device of the present invention, Figs. 2 to 12 are time charts showing its operation, and Figs. 13 and 14 are It is a figure showing an attached state. Hereinafter, the principle of operation of the present invention will be explained before explaining the embodiments. The operation of the present invention can be broadly divided into the following two modes: Mode A; Snow accumulation detection mode; Mode B; Minute snow accumulation (snow covering state) detection mode, and each mode is further divided into finer modes. Note that modes A and B can be switched by a snow detection mode changeover switch, which will be described later. FIG. 15 is a diagram showing each detection area in mode A, where 1 is the sensor section and ROOF is the roof. Therefore, L _TH is the snow detection level,
Snow level at which you want to turn on snow melting equipment, etc. (snow height)
shows. Note that this setting is performed by the user operating a switch or the like (for example, selecting from three levels of setting values). Further, each region shown in the figure is as follows. Area: Area from the roof surface to snow detection level L _TH (length is x) Area: Area from snow detection level L _TH to the end of the non-detection area (length is L) Area: Sensor Non-detection area below part 1 (length is l) Area: Non-detection area above sensor part 1 Therefore, sensor part 1 transmits ultrasonic waves to the roof ROOF, and the reflected waves are It receives the wave and detects from which area the reflection is coming from based on the time from sending the wave to receiving the wave, and depending on the state, it is possible to classify the mode as shown in the table below. By the way, the case where the roof heater is operated by the output of the snow detection device is shown.

〔mode〕

This mode is the case where there is no reflected wave in both the area and the area. This indicates, for example, that the region or regions are covered with snow and that the reflected waves are completely hidden within the transmission time or reverberation time of the vibrator. Therefore, it may be determined that the snowfall is equal to or higher than the snowfall detection level _LTH , and the roof heater may be turned on. [Mode] This mode is a case where reflected waves exist only in a region. This means, for example, that a roof with zero snowfall
This occurs when there is a reflected wave from the ROOF, or when there is snow below the snow detection level _LTH .
Therefore, in this state, the snowfall is at the snowfall detection level L _TH
It may be determined that the following conditions are met and the roof heater may be turned off. [Mode] This mode is when reflected waves exist in the area. This occurs when there is snow in the area that exceeds the set snow detection level _LTH , or when there is snow in the area and its multiple reflections appear in the area. Therefore, it may be determined that the snowfall is at or above the snowfall detection level _LTH , and the roof heater may be turned on. [Mode] This mode is when there are reflected waves in both the area and the area. This is a case where there is snow in the area exceeding the set snow detection level L _TH and multiple reflections of it are also appearing in the area. Therefore, it may be determined that the snowfall is at or above the snowfall detection level _LTH , and the roof heater may be turned on. By dividing into modes in this way and sending snow detection signals according to each mode, a detection operation can be performed even when there is snow that reaches a non-detection area. Next, FIG. 16 is a diagram showing each detection area of mode B. Mode A sets a detailed mode based on the reflection time of the reflected ultrasonic wave, but in addition to that, mode B determines the snow cover condition of a small amount of snow based on the reflection level of the reflected wave, and sets a detailed mode. stipulates. In FIG. 16, each area is as follows. Area: Area from the roof surface to snow detection level L _TH ′ (length is x′) Area: Area from snow detection level L _TH ′ to snow detection level L _TH in mode A (length is x− x′) Area: Same as mode A area. Area: Same as mode A area. Area: Same as mode A area. Thus, the sensor section 1 transmits ultrasonic waves to the roof ROOF and receives the reflected waves. here,
If there is no snow at all and the received wave level is E _R1 when an ultrasonic wave hits the roof ROOF directly, then if there is snow, the ultrasonic wave will be absorbed or reflected diffusely by the snow.
The received level of the reflected wave becomes smaller than E _R1 . Therefore, if the received wave level is E _R2 when the snow starts to accumulate on the roof and reaches the snow detection level L _TH ′ at which you want to turn on the snow melting device, then consider whether the received wave level is smaller than E _R2 when making a judgment. This makes it possible to detect minute amounts of snow. In addition, snow detection level
L _TH ′ is extremely small compared to the mode A snow detection level L _TH . In addition, even if the snowfall height increases further, at least the snowfall detection level of mode A will be maintained.
It has been confirmed that the received wave level does not increase more than at the snow detection level L _TH ′ until it exceeds L _TH . On the other hand, the received wave level E _R2 when the snow height reaches the snow detection level L _TH ′ and the received wave level E _R1 when there is no snow cover.
When compared, E _R1 ≫ _{E R2} , and the received wave level of the two differs by several times or more. Therefore, the received wave amplification factor and the constant of the subsequent integrating circuit are set so that the received wave level E _R2 when the snow detection level L _TH ' is reached becomes the threshold level. As a result, it was found that mode B can be divided into modes as shown in the table below. Note that a case is shown in which the roof heater is operated based on the output of the snow detection device. In addition, in the table below, "0" means that reflected waves reaching the threshold level are not detected at the set received wave amplification factor, and "1" means that reflected waves reaching the threshold level are detected. It shows.

〔mode'〕

In this mode, the reflected waves are
This is a case where the This is because, for example, there is snow in the area, so the received wave level is low.
This is because there is no reflected wave because it does not become larger than E _R2 . Therefore, it may be determined that the snowfall is equal to or higher than the snowfall detection levels L _TH ′, L _TH and the roof heater may be turned on. That is, by sharing the determination logic with mode A, a state similar to mode A is achieved. Note that the difference from mode A is that the reflected wave is not hidden within the reverberation time and does not exist anywhere. [Mode'] This mode is a case where reflected waves exist only in a region. For example, if there is no snow on the roof
This is the case when there is a reflected wave from the ROOF, or when the snowfall is below the snowfall detection level L _TH '. That is, if the snowfall is below the snowfall detection level L _TH ', the received wave level will always be higher than E _R2 , and therefore will be above the threshold level, and there will be a reflected wave. Therefore, in this state, it may be determined that the snowfall is below the snowfall detection level L _TH ', and the roof heater may be turned off. [Mode'] This mode is when a reflected wave exists in the area. This is because there is residual snow with extremely high reflectance in the area, or there is snow remaining in the area.
This is a case where multiple reflections appear in the area. Therefore, it may be determined that the snowfall is equal to or higher than the snowfall detection levels L _TH ′, L _TH and the roof heater may be turned on. [Mode'] This mode is a case where reflected waves do not exist over the entire area from area to area. this is,
For example, if there is snow covering the area and it is leftover snow, this occurs when the reflected wave is completely hidden within the reverberation time of the vibrator. Furthermore, in the case of fresh snow, etc., this occurs when there is no reflected wave over the entire area from area to area due to absorption.
Therefore, it may be determined that the snowfall is equal to or higher than the snowfall detection levels L _TH ′, L _TH and the roof heater may be turned on. [Mode'] This mode is when there are reflected waves in both regions. This means that there is snow in the area exceeding the snow detection level L _TH in mode A,
This is a case where the multiple reflections also appear in the mode A region. Therefore, the snowfall is at the snowfall detection level.
L _TH ′, It is determined that the temperature is higher than L _TH and the roof heater can be turned on. In this way, by sharing the logic with mode A, mode B can be divided into modes in the same way as mode A, and by sending snow detection signals according to each mode, it can be used to detect reflected waves only in areas. It is possible to perform a detection operation such as turning off the roof heater in any other state, and turning on the roof heater in any other state. Next, referring back to FIG. 1, an embodiment of the present invention will be described. In Fig. 1, 1 is a sensor unit that transmits and receives ultrasonic waves, 2 is a distribution board, and 3 is connected to the sensor unit 1 and distribution board 2 to detect snow accumulation and control snow melting operations. This is the detection circuit section. Well, H is the roof heater installed on the roof ROOF, and AC is the commercial power supply. Furthermore, in a snow melting device that pumps up groundwater, seawater, etc. and discharges it through a snow melting pipe to melt snow on roofs and roads, a snow melting pump is used in place of the roof heater H. FIGS. 13 and 14 show examples of installation in a house; FIG. 13 shows the case where a roof heater is used, and FIG. 14 shows the case where a snow removal pump is used. In the figure, 4 is a support for attaching the sensor part 1 to a predetermined position on the roof ROOF, 5 and 7 are wiring cords, 6 is a detection circuit box, P is a snow removal pump, SP is a snow removal pipe, and S is a snow removal pipe. be. Returning to FIG. 1 and explaining the other configuration, the wave transmission circuit of the sensor unit 1 is connected to the wave transmission cycle setting circuit 11, the wave transmission width setting circuit 12, the reference oscillation circuit 13, and the wave transmission circuit 14 in the detection circuit unit 3. An intermittently generated ultrasonic signal is applied to the transmitter circuit 15, and the output of the wave transmitter circuit 15 drives a vibrator 16 provided in the sensor section 1. Furthermore, the vibrator 16 is used for both transmitting and receiving purposes, and the signal generated at both ends of the vibrator passes through the receiving head amplifier 17 in the sensor section 1 and then is switched by the snow detection mode changeover switch 29 in the detection circuit section 3. It is switched to either mode A detection circuit 32 or mode B detection circuit 33, and the output signals of mode A detection circuit 32 and mode B detection circuit 33 are connected to AND gates AND ₁ , AND ₂
It is designed to be commonly applied to one input terminal of the . Here, mode A detection circuit 32 and mode B
The detection circuit 33 will be explained. First, mode A
The detection circuit 32 has a receiving amplifier circuit 18, 19 and an integrating circuit 20 connected in cascade, whereas the mode B detecting circuit 33 has a receiving amplifier circuit 30 and an integrating circuit 31 connected in cascade. The difference between the two lies in the received wave amplification factor and the comparator level of the integrating circuit (A-D conversion circuit), and there is a difference in the appearance of the detection signal caused by this. That is, since the mode A detection circuit 32 has a high received wave amplification factor, it outputs all detection signals regardless of the snow quality of the snow that exists on the roof surface, the area, and a part of the area, and performs the AND gate AND ₁ , AND _However , since the Mode B detection circuit 33 has a low receiving amplification factor, the ultrasonic wave cannot be absorbed by the roof surface without snow, or within a few millimeters of snow starting to accumulate on the roof surface. A detection signal is output and applied to one input terminal of the AND gates AND ₁ and AND ₂ only when the snow is below the snow detection level L _TH ′ or when the snow quality is extremely high in reflectance. Note that since the received wave amplification factor is low in this area, no detection output is given regardless of the snow quality. To explain other configurations in FIG. 1, the output of the wave transmission cycle setting circuit 11 includes a non-detection area gate setting circuit 21, a snow detection area gate setting circuit 22,
The snow detection area gate setting circuits 24 are connected in sequence, the output of the snow detection area gate setting circuit 24 is given to the other input terminal of the AND gate AND ₁ , and the snow detection area gate setting circuit 24 is given to the other input terminal of the AND gate AND ₂ . The output of the gate setting circuit 22 is applied thereto. The snow detection area gate setting circuit 22 includes a plurality of snow detection area gate setting circuits 22-1 to 22-n provided in parallel, and the snow detection area gate setting circuit 22-n is set by operating the snow detection level setting switch 23. 1-2
Any one of 2-n is selected. Next, the output terminals of the AND gates AND ₁ and AND ₂ are connected to one input terminal of the flip-flops _{FF 1 and} FF ₂ , respectively _.
The output of the transmission cycle setting circuit 11 is commonly given to the other input terminal of the flip-flops FF ₁ ,
The output of FF ₂ is provided to a snow detection/judgment circuit 25. Next, the output of the snow detection and determination circuit 25 is sent to an output circuit 26, and the output of this output circuit 26 is provided to a roof heater control section 27 in the distribution board 2. Note that the roof heater control section 2
7 receives a signal indicating snowfall (snowfall detection signal) from the output circuit 26 and connects the commercial power AC to the roof heater H.
performs the operation of supplying the Further, 28 is a power supply circuit for supplying DC power to each part in the detection circuit section 3. The operation will be explained below according to the time charts shown in FIGS. 2 to 12. In addition, each signal shows the waveform of the point with the same symbol in Fig. 1, Fig. 2 shows the waveform common to modes A and B, and Figs. 3 to 6 show the waveform of each mode in mode A. , FIGS. 7 to 12 show waveforms of each mode in mode B. First, FIG. 2 shows the relationship between the timing of wave transmission and the signals of the non-detection area gate setting circuit 21, the snow detection area gate setting circuit 22, and the snow detection area gate setting circuit 24. That is, the non-detection area gate setting circuit 21 generates a signal G 1 having a width of T ₁ from the rising edge of the output of the transmission cycle setting circuit 11 , and the snow detection area gate setting circuit 22 generates a signal G ₁ having a width of T 1 from the rise of the output of the transmission cycle setting circuit 11 . Signals G ₂₁ to _{G 2o} having a width of T ₂₁ to T _2o are generated from the falling edge of the signal G 1 . The snow detection area gate setting circuit 24 also outputs the output signal of the snow detection area gate setting circuit 22.
From the falling edge of the selected one among G ₂₁ ~ _{G 2o}
Signals G ₃₁ to G _3o with a width of T ₃₁ to T _3o are generated. Note that the output signal of the non-detection area gate setting circuit 21
_The width T ₁ of _{G 1} corresponds to _the distance l _{of the} area in _FIG . Corresponding to the area distance L, the width T ₃ (T ₃₁ - G _3o ) of the output signal G ₃ (G 31 - G _3o ) of the snow detection area gate setting circuit 24 is
T _3o ) corresponds to the distance x of the region. Next, FIGS. 3 to 6 show the waveforms of each mode in mode A, and FIGS. 7 to 12 show the waveforms of each mode in mode B. Thus, the transmission cycle setting circuit 11 sends out the signal S ₁ at a predetermined transmission cycle, and the transmission width setting circuit 12 processes the signal S ₂ into a signal S ₂ having a predetermined transmission width T 2 . Next, the reference oscillation circuit 13 generates a signal (ultrasonic signal) _S3 of frequency f during the period when the high-level signal is given from the transmission width setting circuit 12, and the signal is adjusted to a predetermined level by the transmission circuits 14 and 15. It is amplified and given to the vibrator 16. Note that the signal S ₅ on the output side of the wave transmitting circuit 15 has reverberation as shown in a, and if there is reflection, reflected waves b and c appear. Further, the signal _S5 appearing at both ends of the vibrator 16 is sent to the receiving head amplifier 17, the receiving amplifying circuits 18, 19, or the receiving head amplifier 17, the receiving amplifying circuit 30.
are respectively amplified to a predetermined level via R ₃
Alternatively, it is a signal having a rectangular envelope like _R5 . Next, this signal R ₃ or R ₅ is converted into a signal R ₄ or R 5 by the integrating circuit 20 or 31.
The high frequency component is removed and the signal rises slowly like R ₆ , and the AND gate AND ₁ , AND ₂
is applied to one input terminal of Note that by providing the integrating circuits 20 and 31 in this manner, malfunctions due to noise can be prevented. Therefore, in the AND gate AND ₁ , the integration circuit ₂₀ or
When the output signal R ₄ or R ₆ of 1 becomes high level, the ANDed signal becomes high level, indicating that there is reflection from the region or regions. However, in mode B, no reflection from the area can occur. Furthermore, in the AND gate AND _2, if the output signal R ₄ or R ₆ of the integrating circuit 20 or 31 is at a high level during the period when the output signal G ₂ of the snow detection area gate setting circuit 22 is at a high level, the AND gate is processed. The signal with a high level indicates that there is a reflection from the area or area. Note that since these signals can only be obtained for a short period of time, they are held by flip-flops FF ₁ and FF ₂ and output as signals P ₁₁ and P ₁₂ . Next, the snow detection/judgment circuit 25 performs the logical operations shown in the above table as turning on/off the roof heater, and sends out a snow detection signal. As a result, the roof heater control section 27 of the distribution board 2 operates via the output circuit 26, and the roof heater H is connected to the commercial power AC.
The snow melting operation is performed by supplying more power. (Effects of the Invention) As described above, according to the present invention, ultrasonic waves are emitted, the snow height is measured from the reflection time, and when the snow height exceeds a predetermined value, the detection operation is performed. The detection device includes a transducer that emits ultrasonic waves and receives the reflected waves, a detection circuit section in snow detection mode that highly amplifies the reflected waves from the reflective surface facing the transducer, and the transducer and receiver. A detection circuit for a minute snow detection mode that low-amplifies reflected waves within a certain range from a reflecting surface when the snow height facing the transducer is small, and multiple sensors set according to the distance from the transducer. An area gate setting circuit corresponding to each area is provided, and in the case of normal snow height measurement, the snow area is detected by the output from the detection circuit section in the snow detection mode and the output from the area gate setting circuit, and minute snow accumulation is detected. When detecting the presence or absence of snow, it is done by the output from the detection circuit section of the minute snow accumulation detection mode and the output from the area gate setting circuit. In addition to this operation, it can also detect the state of evenly piled-up snow (5 to 10 mm), making it compatible with a variety of snow melting methods. (b) Since the two detection modes can be performed by sharing most of the circuit parts, no increase in cost is caused. (c) In the case of a snow melting device using a snow pipe, even if the user turns off the power to the snow detection device or snow melting device and goes on a trip, etc., and it snows heavily during that time,
By operating in mode B after returning home, the snow melting device can be operated until the roof surface is completely free of snow. There are other effects.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing one embodiment of the ultrasonic snow detection device of the present invention, and FIGS.
Figure 2 is a time chart showing its operation, Figures 13 and 14 are diagrams showing how it is installed in a house, Figures 15 and 16 are explanatory diagrams of the detection area, Figure 1
Figure 7 is a conceptual diagram of snow detection using ultrasonic waves. 1... Sensor section, 2... Distribution board, 3... Detection circuit section, 4... Support column, 5, 7... Wiring cord, 6...
...Detection circuit box, H...Roof heater, P...
... Snow removal pump, SP ... Snow removal pipe, 29 ... Snow accumulation detection mode changeover switch, 32 ... Mode A detection circuit, 33 ... Mode B detection circuit.

Claims (1)

[Claims] 1. An ultrasonic snow detection device that emits ultrasonic waves, measures snow height from the emission time, and detects when the snow height exceeds a predetermined value, comprising: , a transducer that receives this emitted wave, a detection circuit section in a snow detection mode that highly amplifies the reflected wave from a reflective surface facing this transducer, and when the snow height facing this transducer is small. A detection circuit for a micro-snow detection mode that low-amplifies reflected waves of a certain level from the reflecting surface of the transducer, and an area gate setting circuit corresponding to each of the multiple areas set according to the distance from the transducer. In the case of normal snow height measurement, the snow area is detected by the output from the detection circuit section in the snow detection mode and the output from the area gate setting circuit, and in the case of detecting the presence or absence of minute snow accumulation, the A snow detection device using ultrasonic waves, characterized in that the detection is performed using an output from a detection circuit section in a minute snow accumulation detection mode and an output from the area gate setting circuit.