JP2009302612A - Observation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable always unfailingly transmitting observation data to a center device while preventing erroneous operation because of line switching caused by crosstalk in an observation device for transmitting and receiving data with the center device selectively using a wired line and a wireless line. <P>SOLUTION: The observation device includes: a squelch detection section 17 for detecting a squelch signal generated during transmission reception operation by a wireless line 4; a timer section 18 for counting the continuous time of the squelch signal detected by the squelch detection section 17; a discriminating means 11 for discriminating whether or not the continuous time of the squelch signal counted by the timer section 18 is not less than a predetermined value previously set; and a branch input output section 15 for switching between transmission/reception by the wired line 3 and the wireless line 4 based on a result of discrimination of the discriminating means 11. Only when the continuing time of the squelch signal exceeds the predetermined value, the wireless line 4 is selected. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an observation apparatus that is applied to transmission / reception of observation data such as river level and rainfall in a discharge warning system, for example.

  For example, in a discharge alarm system, observation devices such as water level and rainfall of rivers obtained by water level meters and water meters are collected by installing observation devices at multiple locations along the river, while the center device provided in the monitoring center In Japan, the observation data obtained by each observation device is collected to monitor rivers and control sluices, etc., and when the river water level exceeds the dangerous water level, disaster prevention alerts to the surroundings of rivers and to specified institutions, etc. Is coming out.

  Conventionally, in such a system, the observation data such as the river level and rainfall collected by each observation device is transmitted to the center device, or a data transmission request for collecting observation data from the center device to the observation device is made. For this purpose, there is a configuration in which each observation apparatus and the center apparatus are connected to each other via a wireless line and a wired line. The reason why the two lines of the wireless line and the wired line are always provided is that it is necessary to sufficiently ensure safety and reliability in system operation.

  In the prior art, when a problem such as disconnection of a wired line or poor communication of a wireless line occurs, observation data is lost by switching from the wired line to the wireless line or from the wireless line to the wired line. This is prevented (for example, see Patent Document 1 below).

  In this case, in the prior art, the observation apparatus performs line switching by detecting a squelch signal generated in association with a radio signal transmission / reception operation. That is, conventionally, when the observation device wirelessly receives an observation data transmission request from the center device, or when the observation device wirelessly transmits observation data to the center device, for example, an AF signal (tone) is used as the wireless signal. Therefore, a squelch signal is generated from the transmitter / receiver along with such a transmission / reception operation. Then, on the observation device side, when this quelch signal is detected, the wired line is switched to the wireless line to perform wireless transmission / reception, and when no squelch signal is detected, transmission / reception is continued using the wired line.

JP 2002-320285 A

  By the way, a squelch signal may be generated even when an external radio wave (hereinafter referred to as noise) other than a radio signal used for transmission / reception with the center apparatus is mixed and received. Conventionally, line switching is simply performed by detecting the presence or absence of a squelch signal, so that even if a squelch signal is generated due to noise reception, a malfunction occurs in which line switching is performed. In some cases, transmission to the center device could not be performed normally. That is, if line switching is performed due to noise reception, the center apparatus is switched to a wireless line even though it does not send a request to the observation apparatus to transmit observation data wirelessly. Therefore, the center device cannot receive the observation data normally.

  The present invention has been made to solve the above-described problems, and prevents malfunctions such as unconditional line switching when receiving noise, and ensures that observation data is always transmitted to the center device. An object of the present invention is to provide an observation device that can be used.

  In order to achieve the above object, the present invention employs the following configuration in an observation apparatus that transmits and receives data selectively with a center apparatus using a wired line and a wireless line.

  That is, in the present invention, a squelch detection unit that detects a squelch signal generated by a transmission / reception operation of the wireless device, a clocking unit that clocks a duration of the squelch signal detected by the squelch detection unit, and a clocking unit A discriminating means for discriminating whether or not the time duration of the timed squelch signal is greater than or equal to a predetermined value set in advance, and switching for switching between transmission and reception by the wired line and the radio line based on the discrimination result of the discriminating means Means.

  An observation apparatus according to the present invention includes a squelch detection unit that detects a squelch signal generated by a transmission / reception operation of the wireless device, a time measuring unit that measures the duration of the squelch signal detected by the squelch detection unit, and the time measurement Determining means for determining whether or not the duration of the squelch signal timed by the means is equal to or greater than a predetermined value set in advance, and based on the determination result of the determining means, transmission and reception by the wired line and the wireless line are performed. Switching means for switching, so that malfunction of line switching due to noise reception can be prevented, and observation data can always be reliably transmitted to the monitoring center.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing the whole discharge alarm system having an observation device according to Embodiment 1 of the present invention, and FIG. 2 is a block diagram showing the configuration of the observation device applied to the system.

  This discharge warning system includes a wired line 3 and an observation device 1 installed at a plurality of locations along a river and a center device 2 provided in a monitoring center that monitors the state of the river and performs centralized management. They are connected to each other via a wireless line 4. The observation device 1 collects observation data such as river water level and rainfall obtained by a water gauge and rain gauge (not shown) and transmits the data to the center device 2 using the lines 3 and 4, while the center device 2 The transmission request for collecting the observation data obtained by each observation device 1 is transmitted to the observation device 1 using the lines 3 and 4.

  Therefore, when there is a data transmission request from the center apparatus 2, the observation apparatus 1 transmits observation data to the center apparatus 2 via the wired line 3 or the wireless line 4 in response to the request, and the center apparatus 2 receives the received observation. Based on the data, if the river water level exceeds the dangerous water level, a disaster prevention alarm is output to the river area or to a predetermined organization.

  Here, in the observation device 1, the observation data obtained by a water level gauge, a rain gauge, etc. is temporarily stored in a storage device (not shown) in the form of a digital signal in response to a control signal from the CPU 11. Then, when transmitting the observation data to the center device 2, the address setting unit 12 adds a unique address assigned to each observation device 1 to the observation data. The modem 14 converts the observation data to which the address is added into a predetermined frequency modulation signal (FM signal) via the transmission control unit 13.

  A branch input / output unit 15 is connected to the modem 14, and the branch input / output unit 15 is connected to a wired line 3 including a communication cable and a transmitter / receiver 16 for performing wireless communication. Thereby, the branch input / output unit 15 performs line switching for connecting to either the wired line 3 or the wireless line 4 by the transceiver 16 in accordance with a line switching command from the CPU 11. For example, when there is a request for transmission of observation data from the center device 2, the observation device 1 modulates the frequency of the observation data by the modem 14 and transmits it to the center device 2 via the wired line 3 or the wireless line 4. The line switching operation in this case will be described in detail later.

  The squelch detection unit 17 is connected to the transmitter / receiver 16 and detects a squelch signal generated in accordance with the transmission / reception operation of the transmitter / receiver 16. The timer unit 18 measures the duration of the squelch signal detected by the squelch detection unit 17 and sends timer information indicating the measured duration to the CPU 11. Then, the CPU 11 generates a line switching signal for switching between the wireless line 4 and the wired line 3 based on the timer information, and gives it to the branch input / output unit 15. The branch input / output unit 15 performs switching between the wired line 3 and the wireless line 4 by the transmitter / receiver 16 in accordance with the line switching signal.

  In the above configuration, the CPU 11 corresponds to the determination means in the claims, the CPU 11 and the branch input / output unit 15 correspond to the switching means in the claims, and the timer unit 18 corresponds to the time measurement means in the claims. ing.

  Next, the operation of the observation apparatus 1 configured as described above will be described with reference to the flowchart shown in FIG. In the following, the symbol S means each processing step.

  Now, there is a request for transmission of observation data from the center device 2 to the observation device 1 via the wired line 3, and in response to this, the observation device 1 performs frequency modulation of the observation data by the modem 14, It is assumed that the data is transmitted to the center apparatus 2 using the wired line 3 via the branch input / output unit 15 (S1).

  Here, when the transmitter / receiver 16 of the observation device 1 receives a request for transmission of observation data by radio from the center device 2, or when observation data is transmitted from the transmitter / receiver 16 to the center device 2 in response to the transmission request. A squelch signal is generated from the transceiver 16. When neither of these normal transmission / reception operations is performed, a squelch signal is not originally generated from the transmitter / receiver 16. However, a squelch signal is generated even when noise is received by the transceiver 16 due to interference.

  Here, the squelch signal is usually a signal whose H level continues for a certain period, and when a normal transmission / reception operation using the wireless line 4 is performed with the center apparatus 2, the H level period. Is longer than a predetermined value set in advance, and when noise is received, the H level period is shorter than the specified value.

  Therefore, in the first embodiment, when a squelch signal is output from the transceiver 16 and detected by the squelch detection unit 17 (S2), the timer unit 18 is activated in response to this, and the timer unit 181 The reception time during which the squelch signal is continuously received is counted. Then, the timer information of the timer unit 18 is transmitted to the CPU 11 (S3).

  When the timer unit 18 is activated, the CPU 11 sends a line switching signal to the branch input / output unit 15, so that the branch input / output unit 15 connects the modem 14 and the transceiver 16 accordingly. Thereby, the line is once switched from the wired line 3 to the wireless line 4 (S4). Subsequently, the CPU 11 determines whether or not the reception time of the squelch signal is equal to or more than a predetermined value set in advance based on the timer information of the timer unit 18 (step 5).

  Here, when the reception time of the squelch signal is less than a predetermined value set in advance, the CPU 11 receives noise from the transceiver 16 instead of the original squelch signal generated when wirelessly communicating with the center device 2. It is determined that the squelch signal is generated because of being performed (step 6). Then, since the CPU 11 sends a line switching signal to the branch input / output unit 15, the modem 14 and the wired line 3 are connected again, and the transmission returns to the transmission of observation data via the wired line 3 (step 7).

  On the other hand, when the reception time of the squelch signal is equal to or greater than a predetermined value set in advance in S5, the CPU 11 determines that the original squelch signal is generated due to a request for transmission of observation data by radio from the center device 2. (Step 8). In this case, the CPU 11 does not send a line switching signal to the branch input / output unit 15. Therefore, the observation data transmission operation using the wireless line 4 is continuously performed (step 9).

  Note that, after the observation data transmission operation by the transceiver 16 is completed, if no transmission request for observation data by radio is issued from the center device 2, the squelch signal is not detected for a time longer than the specified value, so that the CPU 11 performs branch input / output. A line switching signal is given to the unit 15 to switch from the wireless line 4 to the wired line 3. For this reason, transmission / reception of data using the wired line 3 is executed.

  As described above, according to the first embodiment, when a squelch signal is received, the line is not simply switched from the wired line 3 to the wireless line 4 when the squelch signal is received. Considering time, the line switching from the wired line 3 to the wireless line 4 is performed only when the duration for receiving the squelch signal is equal to or greater than a predetermined value set in advance, so that malfunction of line switching due to noise reception can be prevented. It is possible to transmit the observation data to the center device 2 with certainty at all times.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing the configuration of the observation apparatus according to the second embodiment, and components corresponding to or corresponding to those of the first embodiment shown in FIG.

The feature of the observation apparatus 1 in the second embodiment is that, in addition to the configuration of the first embodiment shown in FIGS. 1 and 2, a carrier signal detection unit 19 that detects a carrier signal included in a radio signal is provided. The CPU 11 uses both the carrier signal detected by the carrier signal detector 19 and the duration of the squelch signal to generate a squelch signal caused by noise reception or between the center device 2 and the squelch signal. In other words, it is determined whether the signal is an original squelch signal generated by wireless communication.
Since other configurations are the same as those of the first embodiment, detailed description thereof is omitted here.

  Next, the operation of the observation apparatus 1 configured as described above will be described with reference to the flowchart shown in FIG.

  In the second embodiment, the operations from S1 to S7 are the same as the operations from S1 to S7 in the first embodiment shown in FIG.

  In the second embodiment, even when it is determined in S5 that the reception time of the squelch signal is equal to or greater than a predetermined value set in advance, the wireless line 4 is not simply used, but from the transceiver 16 Based on the output, the carrier signal detector 19 detects the carrier signal and obtains information on the carrier frequency (S10). Then, it is determined whether the frequency of the carrier signal is the same as the frequency used for wireless communication with the center apparatus 2 (S11).

  At this time, when the frequency of the carrier signal detected by the carrier signal detection unit 19 is different from the frequency used for wireless communication with the center apparatus 2, the CPU 11 transmits and receives the generated squelch signal. The machine 16 determines that the signal is a squelch signal generated by receiving noise (S6), and returns to transmission of observation data via the wired line 3 (S7).

  On the other hand, when the frequency of the carrier signal detected by the carrier signal detection unit 19 in S11 is the same as the frequency used for wireless communication with the center device 2, the CPU 11 (S8), the observation data transmission operation using the wireless line 4 is continued (S9).

  As described above, in the second embodiment, by adding processing (S10, S11) for detecting a carrier signal to the conditions for line switching, noise is continued due to interference over a time exceeding a specified value. Even if the frequency of the carrier signal is not the same as the frequency of the carrier signal used for wireless communication with the center device 2, it can be determined that noise has been received. As a result, it is possible to more reliably prevent malfunction of line switching than in the case of the first embodiment, and normal transmission of observation data becomes possible.

Embodiment 3 FIG.
The configuration of the observation apparatus in the third embodiment is basically the same as that of the second embodiment shown in FIG.

  The third embodiment is different from the second embodiment in that the switching control between the wired line 3 and the wireless line 4 by the CPU 11 is slightly changed. That is, in the above-described second embodiment, after determining whether the reception time of the squelch signal is equal to or greater than the specified value (S5), the same frequency as that of the carrier signal used for wireless communication with the center apparatus 2 is determined. In the third embodiment, conversely, whether or not the frequency of the carrier signal used for wireless communication with the center apparatus 2 is the same is determined. The determination (S11) is executed first, and thereafter, it is determined (S5) whether or not the reception time of the squelch signal is equal to or greater than a specified value.

  The operation of the third embodiment will be described below with reference to the flowchart shown in FIG. In FIG. 6, the same reference numerals are assigned to the same processing steps as the processing contents of the flowchart shown in FIG.

  Also in the third embodiment, as in the second embodiment, the observation data is frequency-modulated by the modem 14 by the modem 14 and transmitted to the center device 2 using the wired line 3 (S1). When the squelch signal is detected by the detector 17 (S2), the carrier signal detector 19 detects a carrier signal in wireless communication and obtains information on the carrier frequency (S10).

  Next, since the CPU 11 sends a line switching signal to the branch input / output unit 15, the line can be temporarily switched from the wired line 3 to the wireless line 4 (S4). Subsequently, the CPU 11 determines whether or not the frequency of the carrier signal detected by the carrier signal detection unit 19 is the same as the frequency of the carrier signal used for wireless communication with the center device 2 (S11).

  At this time, if the frequency of the carrier signal is different from the frequency used for wireless communication with the center device 2, the CPU 11 indicates that the squelch signal generated this time is the quelch generated by the transmitter / receiver 16 receiving noise. It is determined that the signal is a signal (S6), and the process returns to the transmission of observation data via the wired line 3 (S7).

  On the other hand, when the frequency of the carrier signal detected by the carrier signal detection unit 19 in S11 is the same as the frequency used for wireless communication with the center device 2, the timer unit 18 continues the squelch signal. The receiving time is counted, and the timer information is sent to the CPU 11. Therefore, the CPU 11 determines whether or not the reception time of the squelch signal is equal to or greater than a predetermined value set in advance based on the timer information of the timer unit 18 (S5).

  At this time, when the CPU 11 determines that the reception time of the squelch signal is less than a preset specified value, the CPU 11 determines that the squelch signal is a squelch signal generated due to reception of noise by the transceiver 16. The process proceeds to S6 and S7.

  On the other hand, when the reception time of the squelch signal is greater than or equal to a predetermined value set in advance in S5, the CPU 11 determines that the original squelch signal is generated when wireless communication is performed with the center device 2 ( S8), the observation data transmission operation using the wireless line 4 is continued (S9).

  As described above, according to the third embodiment, as in the case of the second embodiment, by adding the processing (S10, S11) for detecting the carrier signal to the condition for switching the line, Even if the noise is continuously received for a time longer than the specified value, the noise is received if it is not the same as the frequency of the carrier signal used for the radio signal transmitted to and received from the center apparatus 2. It can be judged. As a result, it is possible to more reliably prevent malfunction of line switching than in the case of the first embodiment, and it is possible to transmit observation data with certainty.

  In addition, this invention is not limited to the structure of said Embodiment 1-3, A various deformation | transformation can be added in the range which does not deviate from the meaning.

It is a block diagram which shows the whole discharge alarm system which has an observation apparatus in Embodiment 1 of this invention. It is a block diagram which shows the structure of the observation apparatus applied to the same system. It is a flowchart with which it uses for operation | movement description of the observation apparatus in Embodiment 1 of this invention. It is a block diagram which shows the structure of the observation apparatus in Embodiment 2 of this invention. It is a flowchart with which it uses for operation | movement description of the observation apparatus in Embodiment 2 of this invention. It is a flowchart with which it uses for operation | movement description of the observation apparatus in Embodiment 3 of this invention.

Explanation of symbols

1 Observation device, 2 Center device, 3 Wired line, 4 Wireless device,
11 CPU (discriminating means), 15 branch input / output section (switching means), 17 squelch detecting section, 18 timer section (time measuring means), 19 carrier signal detecting section.

Claims (4)

An observation device that selectively transmits and receives data with a center line using a wired line and a wireless line,
A squelch detection unit for detecting a squelch signal generated by a transmission / reception operation by the wireless line, a time measuring unit for measuring the duration of the squelch signal detected by the squelch detection unit, and the squelch signal timed by the time measuring unit Determining means for determining whether or not the duration time is equal to or greater than a predetermined value set in advance, and switching means for switching between transmission and reception by the wired line and the wireless line based on the determination result of the determining means An observation device characterized by When the determining means determines that the duration of the squelch signal is greater than or equal to a specified value, the switching means transmits and receives data via the wireless line, while the duration is less than the specified value. 2. The observation apparatus according to claim 1, wherein, when it is determined, data is transmitted and received through the wired line. Carrier signal detecting means for detecting presence / absence of a carrier signal used for transmission / reception with the center apparatus via a radio channel is provided, and the switching means is detected by the duration of the squelch signal and the carrier signal detecting means. 3. The observation apparatus according to claim 1, wherein transmission / reception by the wired line and the wireless line is switched based on presence / absence of a carrier signal. When the discriminating means determines that the duration of the squelch signal is equal to or longer than a specified value, and the carrier signal is detected by the carrier signal detecting means, the switching means transmits and receives data via the wireless line. On the other hand, if it is determined by the determining means that the duration of the squelch signal is less than a specified value, or if no carrier signal is detected by the carrier signal detecting means, data transmission / reception is performed via the wired line. The observation apparatus according to claim 3, wherein the observation apparatus is a thing.

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