JP2001027679A - Snowfall-detecting apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a snowfall-detecting apparatus which can surely grasp a snowfall intensity and can also reduce costs of a signal line. SOLUTION: A snowfall intensity is judged on the basis of signals of each electrode pair 2 set to a plurality of points of a snow-receiving plate 1a, so that the snowfall intensity can be surely grasped. In this case, each rectifying smoothing circuit 6 set for each electrode pair 2 is arranged to the side of a detector body 1. Signals of the electrode pairs 2 are sequentially changed over by a signal switch circuit 7 to be outputted to a control circuit 11 of a control part body 10. Therefore, the need of setting a signal line 12b of a cable 12 for connecting the detector body 1 with the control part body 10 for each electrode pair 2 is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a snowfall detecting device for a snowmelting device used on a road in a snowfall zone.

[0002]

2. Description of the Related Art Conventionally, as this type of snowfall detection device,
For example, as described in Japanese Utility Model Publication No. Sho 62-37183, a snow receiving plate having a pair of electrodes on its surface and an outside air temperature sensor for detecting an outside air temperature are provided. When the temperature drops below the temperature and it is detected that the snow falls on the snow receiving plate and the electrodes are electrically connected to each other due to the water content of the snow particles, a snow melting device installed on a road or the like is operated. Have been.

By the way, the snowfall detecting device can detect the intensity of snowfall by measuring the evaporation time of the snowdrops attached to the snowplate, but the snowdrops on the snowplate completely evaporate. If there is a large amount of snowfall before the next snow particle adheres, the electrodes of the snow receiving plate will be in a continuous conduction state, so the intensity of snowfall cannot be detected, and the operation of the snow melting device will not be possible. There is a disadvantage that it cannot be properly controlled according to the snowfall intensity.

Accordingly, the applicant has proposed a plurality of electrode pairs each having a pair of electrodes arranged at predetermined positions on the surface of a snow plate, a signal switching circuit for sequentially switching signals of each electrode pair, and a signal switching circuit. (Japanese Patent Application No. 10-327772) has already proposed a snowfall detection device including control means for determining the snowfall intensity based on the signal of each electrode pair switched by the above and the temperature detected by the outside air temperature sensor.

According to this snowfall detection device, the snowfall intensity is determined based on the signals of the respective electrode pairs provided at a plurality of locations on the snow-receiving plate, so that the snowfall intensity can be accurately grasped.

[0006]

However, as described above, the snowfall detecting device in which a plurality of electrode pairs are provided on the snow receiving plate has the advantage that the snowfall intensity can be grasped based on the signal of each electrode pair. A signal line for connecting each electrode pair of the snow plate and the control unit main body arranged at a remote position of the snow plate is required for each electrode pair, and a problem with the cost of the signal line remains. In addition, since the signal line from the snow plate has a high impedance and is easily affected by noise, there is a possibility that the signal line may become an obstacle when the signal line is lengthened.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a snowfall detection device capable of accurately grasping the snowfall intensity and reducing the cost of signal lines. It is to provide a device. Also,
Another object of the present invention is to reduce the influence of noise in addition to the above objects.

[0008]

In order to achieve the above object, according to the present invention, in the first aspect, a detector main body installed at a snowfall detection location and a surface of the detector main body are provided with the surface facing upward. A snow plate, a plurality of electrode pairs each having a pair of electrodes disposed at predetermined positions on the surface of the snow plate, a signal switching circuit for sequentially switching signals of each electrode pair, and an outside air temperature for detecting an outside air temperature A sensor and control means for determining a snowfall intensity based on a signal of each electrode pair switched by a signal switching circuit and a temperature detected by an outside air temperature sensor, wherein the signal switching circuit is connected to a detector body side And the control means is disposed in a control unit main body located remote from the detector main body, and the signal switching circuit and the control means are connected by a signal line. As a result, the signal of each electrode pair is sequentially switched by the signal switching circuit on the detector main body side and output to the control means on the control unit main body side, so that the signal for connecting the detector main body side and the control unit main body side is output. There is no need to provide a line for each electrode pair.

According to a second aspect of the present invention, in the snowfall detecting device according to the first aspect, the outside air temperature sensor is disposed on the detector main body side, and the outside air temperature sensor is connected to the signal switching circuit. The signals of each electrode pair and the outside air temperature sensor are sequentially switched. Thus, in addition to the function of claim 1, the detection signal of the outside air temperature sensor is input to the signal switching circuit, is switched to the signal of each electrode pair, and is output to the control means side. Need not be provided separately.

According to a third aspect of the present invention, in the snowfall detecting device according to the first or second aspect, a snow plate temperature sensor for detecting a temperature of the snow plate, a heating means for heating the snow plate,
Control means for controlling the heating means so that the temperature of the snow plate becomes a predetermined set temperature, a snow plate temperature sensor is connected to the signal switching circuit, and each of the electrode pairs and the snow plate is connected by the signal switching circuit. The signals of the temperature sensors are sequentially switched. Thereby, in addition to the function of claim 1 or 2, the detection signal of the snow plate temperature sensor is input to the signal switching circuit,
Since the signal is switched to the signal of each electrode pair and output to the control means side, it is not necessary to separately provide a signal line of the snow plate temperature sensor.

According to a fourth aspect, in the snowfall detecting device according to the first, second or third aspect, an amplifier circuit for amplifying an output signal of the signal switching circuit is provided on the detector main body side. Thereby, in addition to the effect of claim 1, 2 or 3,
Since the output signal of the signal switching circuit is amplified, the impedance of the signal line connecting the detector main body side and the control unit main body side is reduced, and the influence of noise is reduced.

[0012]

1 to 5 show an embodiment of the present invention. FIG. 1 is a schematic structural view of a snowfall detecting device, FIG. 2 is an exploded perspective view of a detector main body, and FIG. Side sectional view,
FIG. 4 is a side sectional view of a main part of a snow plate, and FIG. 5 is a circuit diagram of an electrode.

This snowfall detection device includes a detector body 1 installed at an arbitrary snowfall detection location, a snow plate 1a provided on the detector body 1 with its surface facing upward, and a surface of the snow plate 1a. A plurality of electrode pairs 2, a heater 3 for heating the snow plate 1a, a snow plate temperature sensor 4 for detecting the temperature of the snow plate 1a, an outside air temperature sensor 5 for detecting the outside air temperature, A plurality of rectifying / smoothing circuits 6 for rectifying / smoothing the signals from each electrode pair 2, each electrode pair 2 and each temperature sensor 4, 5
Signal switching circuit 7 for sequentially switching and outputting the signals, an amplifying circuit 8 for amplifying the output signal of the signal switching circuit 7, a circuit board 9 arranged on the detector main body 1 side, and a detector main body 1. It comprises a control unit main body 10 installed remotely, a control circuit 11 arranged on the control unit main body 10 side, and a cable 12 connecting the detector main unit 1 and the control unit main body 10.

The detector main body 1 has a case 1c having an opening 1b on the upper surface side, and the case 1c is fixed at one end to a column 1d. A sensor housing 1e for housing the outside air temperature sensor 5 is integrally provided on the lower surface side of the case 1c, and a plurality of ventilation holes 1f for inflow of outside air are provided in the sensor housing 1e and a part of the case 1b. .

The snow plate 1a is formed of an insulating material, and is attached to the opening 1b of the detector main body 1 with its surface facing outward.

Each electrode pair 2 has a pair of electrodes 2a.
The electrodes 2a are formed in a comb shape so as to be close to each other. As shown in FIG. 4, each electrode 2a extends through the snow receiving plate 1a from the front surface to the back surface of the snow receiving plate 1a.
b and the carbon coating 2c. In this case, one electrode 2a of each electrode pair 2 is
On the back surface of a, they are formed in an integrated pattern with each other, and are connected to one end of a power supply 2d via a common wiring. The other electrode 2a of each electrode pair 2 is connected to each rectifying / smoothing circuit 6 by an individual wiring.

The heater 3 is composed of a plurality of heating elements, and is attached to the heat transfer plate 3a which is in surface contact with the back surface of the snow plate 1a and the inner side surface of the case 1c.
Is to be heated.

The snow plate temperature sensor 4 comprises a temperature detecting element for detecting a temperature as an electric signal, and is mounted in the detector main body 1 (not shown) so as to be in contact with the snow plate 1a. The snow plate temperature sensor 4 is connected to a signal switching circuit 7 via a resistance voltage dividing circuit 4a.

The outside air temperature sensor 5 comprises a temperature detecting element for detecting a temperature as an electric signal, and is arranged in the sensor housing 1e of the detector main body 1. Further, the outside air temperature sensor 5 is connected to the signal switching circuit 7 via the resistance voltage dividing circuit 5a.

Each of the rectifying / smoothing circuits 6, the signal switching circuit 7, the amplifying circuit 8, and each of the resistance voltage dividing circuits 4a and 5a are provided on a circuit board 9, and the circuit board 9 is accommodated in a case 1c of the detector main body 1. I have.

The control unit main body 10 includes various operation switches, a power supply and the like, and stores a control circuit 11.

The control circuit 11 is constituted by a microcomputer, and is connected to the signal switching circuit 7, the amplifier circuit 8, and the heater 3. Further, the control circuit 11 includes a relay 11
a is connected to a boiler A of the snow melting apparatus. The control circuit 11 sends a pulse signal of a predetermined frequency to the signal switching circuit 7, and amplifies the signals of the electrode pairs 2, the snow plate temperature sensor 4 and the outside air temperature sensor 5, which are sequentially switched in synchronization with the pulse signal. Input through a circuit 8,
The boiler A and the heater 3 are respectively controlled based on these signals.

The cable 12 has a signal line 12 connected at one end to the signal switching circuit 7 and the amplifying circuit 8 on the detector body 1 side.
a, 12b, and a power line 12c, 1 having one end connected to the heater 3, the power supply terminal, and the ground on the detector main body 1 side.
2d and 12e. These signal lines 12a and 12e
b and the other ends of the conductors 12c, 12d, and 12e are connected to the control circuit 11.

In the snowfall detecting device configured as described above, first, the signal of each electrode pair 2 is input to each rectifying / smoothing circuit 6, and the signal of each electrode pair 2 is input to each rectifying / smoothing circuit 6.
And then input to the signal switching circuit 7. The detection signals from the snow plate temperature sensor 4 and the outside air temperature sensor 5 are input to the signal switching circuit 7 via the resistance voltage dividing circuits 4a and 5a, respectively. Next, the signal switching circuit 7
Are synchronized with the pulse signal from the control circuit 11 for each electrode pair 2
The signals of the temperature sensors 4 and 5 are sequentially switched, and the signals are output to the control circuit 11 via the amplifier circuit 8. Here, when each electrode 2a of each electrode pair 2 becomes electrically conductive due to the moisture of the snow particles attached to the snow plate 1a, a change in the signal of each electrode pair 2 is detected by the control circuit 11, and the detection result is obtained. The opening / closing of the relay 11a, that is, the operation and stop of the boiler A are performed based on the operation. The control circuit 11 detects, for example, a change in the voltage of the signal of each electrode pair 2 and, when the signal of each electrode pair 2 exceeds a predetermined reference voltage, counts the number of times that the signal exceeds the reference voltage per unit time. Counting is performed, and the snowfall intensity is determined based on the counting result. In this case, if the detected temperature of the outside air temperature sensor 5 is not lower than the snowfall temperature (for example, 0 ° C.), the counting process is not performed even if the signal of each electrode pair 2 exceeds a predetermined reference voltage. When the unit time elapses, the count data is reset to zero. Furthermore,
The control circuit 11 controls the driving power of the heater 3 so that the temperature detected by the snow plate temperature sensor 4 becomes a predetermined set temperature.

As described above, according to the snowfall detection device of this embodiment, the snowfall intensity is determined based on the signals of the electrode pairs 2 provided at a plurality of locations on the snow-receiving plate 1a. The operation of the boiler A can be properly controlled in accordance with the amount of snowfall. in this case,
Each rectifying / smoothing circuit 6 provided for each electrode pair 2 is arranged on the detector main body 1 side, and a signal of each electrode pair 2 is switched to a signal switching circuit 7.
Control circuit 11 of the control unit body 10
The signal line 12b of the cable 12 connecting the detector main body 1 side and the control unit main body 10 side does not need to be provided for each electrode pair 2, and the cost of the cable 12 can be reduced. Can be. In this case, the signal switching circuit 7
Is amplified by the amplifier circuit 8, the impedance of the signal line 12b of the cable 12 is reduced, and the influence of noise can be greatly reduced.
Also, the detection signals of the snow plate temperature sensor 4 and the outside air temperature sensor 5 are converted into signal switching circuits 7 through resistance voltage dividing circuits 4a and 5a.
To the control circuit 11 by switching to the signal of each electrode pair 2.
Since the signal is output to the side, there is no need to separately provide signal lines for the temperature sensors 4 and 5 on the cable 12, and the cost of the cable 12 can be further reduced.

In the above embodiment, the determination of the snowfall intensity is performed by a program stored in the control circuit 11. However, the snowfall intensity determination means is replaced by a voltage comparison circuit,
It is also possible to configure with hardware such as a gate circuit, a counting circuit, and a timing circuit.

[0027]

As described above, according to the snowfall detecting devices of the first, second and third aspects, the snowfall intensity can be accurately grasped, and the detector main body side and the control section main body side are connected. Since it is not necessary to provide a signal line for each of a plurality of electrode pairs, the cost of the signal line can be significantly reduced.

Further, according to the snowfall detecting device of the fourth aspect,
In addition to the effects of claims 1, 2 and 3, the impedance of the signal line connecting the detector main body side and the control unit main body side can be reduced, so that the influence of noise can be greatly reduced and the signal can be reduced. Very long lines are very advantageous.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a snowfall detection device according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of a detector main body.

FIG. 3 is a side sectional view of the detector main body.

FIG. 4 is a side sectional view of a main part of a snow plate.

FIG. 5 is a circuit diagram of an electrode.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Detector main body, 1a ... Snow plate, 2 ... Electrode pair, 2a ... Electrode, 3 ... Heater, 4 ... Snow plate temperature sensor, 5 ... Snow plate temperature sensor, 7 ... Signal switching circuit, 8 ... Amplification Circuit, 10: control unit body, 11: control circuit.

Claims (4)

[Claims] 1. A detector main body installed at a snowfall detection place, a snow receiving plate provided with the surface of the detector main body facing upward, and a pair of electrodes at predetermined locations on the surface of the snow receiving plate. A plurality of electrode pairs arranged, a signal switching circuit for sequentially switching signals of each electrode pair, an outside air temperature sensor for detecting an outside air temperature, and a signal of each electrode pair and an outside air temperature sensor switched by the signal switching circuit. Control means for determining snowfall intensity based on the detected temperature, wherein the signal switching circuit is arranged on the detector body side,
A snowfall detection device, wherein the control means is disposed in a control unit main body located remote from the detector main body, and a signal switching circuit and the control means are connected by a signal line. 2. The outside air temperature sensor is disposed on the detector main body side, and the outside air temperature sensor is connected to the signal switching circuit, and the signal switching circuit sequentially switches signals of each electrode pair and the outside air temperature sensor. The snowfall detection device according to claim 1, wherein: 3. A snow plate temperature sensor for detecting the temperature of the snow plate, a heating unit for heating the snow plate, and a heating unit for controlling the temperature of the snow plate to a predetermined temperature. And a control means, wherein a snow plate temperature sensor is connected to the signal switching circuit, and the signal switching circuit sequentially switches signals of each electrode pair and the snow plate temperature sensor. 2. The snowfall detection device according to 2. 4. The snowfall detection device according to claim 1, wherein an amplification circuit for amplifying an output signal of the signal switching circuit is provided on the detector body side.