JP2007020255A - Data communication system and communication terminal apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To sense an occurrence and a recovery of a power interruption in a communication terminal apparatus and a center apparatus. <P>SOLUTION: The communication terminal apparatus 2 is connected to a router 4 connected to an uninterruptible power supply 9 through a network cable 3. The router 4 supplies defined power to the communication terminal apparatus 2 through the network cable 3 during a normal operation, and supplies predetermined power during the interruption. When the predetermined power is supplied, the communication terminal apparatus 2 determines the power interruption. When the defined power is supplied after that, the communication terminal apparatus 2 determines that the power interruption is recovered. The communication terminal apparatus 2 informs the center apparatus 6 of the occurrence of the power interruption through a network, and informs the center apparatus 6 of the recovery of the power interruption thereafter. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a data communication system that performs data transmission between a center device and a communication terminal device through a network such as a LAN or a WAN.

  For example, there is a data communication system that transmits information on security devices such as meter readings and intrusion sensors such as gas meters and water meters via the Internet. As shown in FIG. 5, a terminal device 1 such as a gas meter, a water meter, and a sensor is connected to a communication terminal device 2 having an IP address, and the communication terminal device 2 is connected to a router 4 by a network cable 3. Then, the communication terminal apparatus 2 communicates with the center apparatus 6 using the Internet from the router 4 through the communication line 5. Data such as a meter reading value from the terminal device 1 is converted into a predetermined data format according to, for example, the TCP / IP protocol by the communication terminal device 2 and transmitted to the center device 6. Conversely, the center device 6 communicates with the communication terminal device 2 according to the TCP / IP protocol and acquires data from the terminal device 1. In the figure, 7 is a router on the center side.

  Such a communication terminal device 2 is generally installed outdoors or on a wall, and a battery is used as a power source. However, since the battery has a lifetime, a commercial power source is used so that the battery can be used stably for a long period of time.

  As described in Non-Patent Document 1, PoE (Power over Ethernet) technology for supplying power to a network via a network cable such as a LAN cable has become widespread.

  If PoE technology is used, network power can be supplied to the communication terminal device 2 from the router 4 via the network cable 3 regardless of the installation location of the communication terminal device 2.

  The router 4 is supplied with power from the commercial power supply 8. However, communication is not possible during a power outage. Therefore, if an uninterruptible power supply (UPS) 9 is connected to the router 4 via the power cable 10, a data communication system that can communicate even when a power failure occurs can be obtained.

  However, since the UPS 9 is a device that uses a secondary battery, if the power outage extends beyond the specifications of the UPS 9, backup becomes impossible and the communication terminal device 2 cannot communicate.

Patent Document 1 proposes that when the UPS detects the occurrence of a power failure, it transmits a power failure notification command to the communication terminal device, and when the communication terminal device receives the power failure notification command, it is proposed to execute a power failure process.
Nikkei NETWORK June 2004, pages 88-92 JP-A-7-225721

  In the case of a data communication system using the PoE technology using the UPS as described above, even if a power failure occurs, the communication terminal device is backed up by the UPS via the router. Operate. Therefore, the occurrence of a power failure cannot be detected as a data communication system. Similarly, even if the power failure is recovered, this cannot be detected.

  On the other hand, the center device continues to operate without knowing that a power failure has occurred on the terminal side. For this reason, when the power failure is prolonged and the UPS power supply is interrupted, the communication is suddenly interrupted and an error occurs. Similarly, the center device does not know that the power failure on the terminal side has recovered, and cannot perform operations such as retransmission after recovery.

  In the method of performing a power failure notification using the power failure notification command in Patent Document 1, when a communication failure occurs, the communication terminal device cannot receive the power failure notification command and cannot perform power failure processing. The same applies when a power failure recovery notification is issued by a power failure recovery command, and power failure recovery processing cannot be performed. Then, it is necessary to newly set a protocol for transmitting and receiving the above command in the communication terminal devices on the power supply side and the power reception side. In addition, since it is not a network power supply, a power cable and a communication cable are required, and the wiring becomes complicated.

  In view of the above, an object of the present invention is to provide a data communication system capable of recognizing a power failure and recovery not only in a communication terminal device but also in a center device.

  The present invention is a data communication system in which a communication terminal device and a center device transmit data through a network, and includes a power supply device that supplies power to the communication terminal device and has a backup power source during a power failure. The device notifies the communication terminal device of the occurrence of a power failure by supplying the communication terminal device with a predetermined power different from the normal power at the time of a power failure. The communication terminal device can operate at a predetermined power during a power failure, and notifies the center device that a power failure has occurred.

  Since the power supply device supplies different power to the communication terminal device depending on the presence or absence of the power failure, the communication terminal device can determine that the power failure has occurred or that the power failure has been recovered by the supplied power. Therefore, the communication terminal apparatus can recognize this even if the power supply apparatus does not notify the occurrence or recovery of the power failure. The center device can also recognize the occurrence or recovery of a power failure by the notification from the communication terminal device.

  Here, the power supply device is a network device that is interposed between the network and the communication terminal device and relays communication between the communication terminal device and the center device, that is, has a backup power supply at the time of a power failure and has a communication relay function. . The power supply apparatus includes an uninterruptible power supply apparatus as a backup power supply, and the power supply apparatus supplies power by switching from specified power to predetermined power in accordance with a power failure detection signal from the uninterruptible power supply apparatus. When there is no power failure detection signal, the specified power is supplied.

  The communication terminal device is connected to the power supply device via a network cable, and the specified power is supplied from the power supply device through the network cable at a normal time, and the predetermined power different from the specified power is supplied at the time of a power failure. A control unit that operates with the power supplied from the power supply device is provided. The control unit determines whether or not a power failure has occurred based on the supplied power, and notifies the center device of the occurrence of the power failure or the recovery from the power failure. A detector for detecting the supplied power is provided, and when the specified power is detected, it is determined that the power source is normal, and when a predetermined power smaller than the specified power is detected, a power failure is determined.

  In addition, when the communication terminal device detects the occurrence or recovery of a power failure during communication with the center device, the communication terminal device notifies the center device after terminating the communication. As a result, communication is not interrupted and no communication error occurs. In other words, unnecessary communication errors can be prevented when the battery capacity of the uninterruptible power supply has a sufficient margin for the power consumption of the communication terminal device or when there is a momentary power failure.

  Alternatively, when the communication terminal device detects the occurrence or recovery of a power failure during communication with the center device, the communication terminal device stops communication and notifies the center device. That is, when the power consumption of the communication terminal device is large, there are multiple communication terminal devices, the load of the uninterruptible power supply is large, the capacity of the uninterruptible power supply is small, etc., the backup power supply cannot withstand a long time However, by notifying the center device immediately, it is possible to prevent communication from becoming impossible and impossible notification.

  When the communication terminal apparatus detects the occurrence or recovery of a power failure during the initial activation, the communication terminal apparatus notifies the center apparatus after the initial activation is completed. If the initial activation is not completed, the communication terminal device cannot communicate with the center device. Therefore, if communication is performed after the initial activation is completed, the notification can be reliably made.

  According to the present invention, by supplying power different from the normal time to a communication terminal device at the time of a power failure, it can be used instead of a signal for notifying a power failure, and there is no need to provide a separate communication circuit or the like. Moreover, the communication terminal device can operate stably even during a power failure and can recognize the power failure. The center device can also recognize the power failure by the notification from the communication terminal device, and can cope with the power failure.

  A data communication system of this embodiment is shown in FIG. In the data communication system, a center device 6 and a communication terminal device 2 on the terminal side are connected via a communication line 5, and a terminal device 1 such as a meter or a sensor connected to the communication terminal device 2 and the center device 6 are connected. A network is formed, and two-way communication is performed through this network, and automatic meter reading and data communication of security information are performed.

  The communication terminal device 2 is connected to the router 4 by a network cable 3 such as a LAN cable. The router 4 is connected to a communication line 5 such as a public telephone line or an optical fiber, and is connected to the Internet network. A router 7 on the center side is connected to the Internet network, and a center device 6 is connected to the router 7. As a result, the center apparatus 6 and the communication terminal apparatus 2 perform data communication using the Internet network through the routers 4 and 7. The communication terminal device 2 transmits data from the terminal device 1 to the center device 6 and receives data from the center device 6 to communicate with the terminal device 1. Note that the number of communication terminal devices 2 connected to the router 4 is not limited to one and may be plural.

  An uninterruptible power supply (UPS) 9 is connected to the router 4. The uninterruptible power supply 9 normally supplies power from the commercial AC power supply 8 to the router 4 through the power cable 10 and charges a built-in battery. On the other hand, when the commercial AC power supply 8 fails, power is supplied from the battery and a power failure detection signal is output to the router 4 through the communication cable 11. When no power failure occurs, the power failure detection signal is not output.

  The router 4 supplies power to the communication terminal device 2 via the network cable 3. That is, the router 4 serves as a power supply device that supplies power to the communication terminal device 2 and has a backup power source during a power failure.

  FIG. 2 shows configurations of the router 4 and the communication terminal device 2. In the router 4, the power supply circuit 12 converts the power from the uninterruptible power supply 9 into power necessary for the operation of the router 4 and also converts it into voltages necessary for the DC power supplies 13 and 14. The DC power supplies 13 and 14 generate power to be supplied to the communication terminal device 2. For example, the DC power supply 13 outputs a specified voltage of 48 V in accordance with the PoE specification, and the DC power supply 14 outputs a predetermined voltage of 35 V that is outside the PoE specification. Outputs of the DC power sources 13 and 14 are switched by the switch 15 and supplied to the power feeding circuit 17. The switch 15 is switch-controlled by the CPU 16 according to the presence or absence of a power failure. When there is no power failure detection signal from the uninterruptible power supply 9, 48V of the DC power source 13 is output. When there is a power failure detection signal, 35V of the DC power supply 14 is output. The power feeding circuit 17 supplies a specified voltage or a predetermined voltage to the communication terminal device 2 using an empty line or a data line of the network cable 3.

  A pulse transformer unit 18 and an Ethernet (registered trademark) transceiver 19 are connected to the network cable 3. The Ethernet transceiver 19 transmits / receives data to / from the network cable 3 by a controller (not shown).

  In the communication terminal device 2, 20 is a pulse transformer unit, and 21 is an Ethernet transceiver that performs data transmission / reception through the network cable 3. 22 is a network controller for controlling communication with the network, 23 is a CPU which is a control unit for controlling the entire communication terminal device, and 24 is a meter interface for communicating with a meter which is the terminal device 2. The network controller 22 converts the data transmitted from the meter in accordance with the TCP / IP protocol, and enables meter reading and control from the center device 6 through the network. A power receiving circuit 25 receives power supplied from an empty line or a data line of the network cable 3. A power supply circuit 26 converts the power received by the power receiving circuit 25 into a voltage necessary for the communication terminal device 2 and supplies the voltage to each member in the device. The communication terminal device 2 normally operates at a low voltage of 3.3V. Therefore, it can operate sufficiently even with 35V supplied during a power failure.

  Reference numeral 27 denotes a voltage detector that detects the voltage supplied to the power receiving circuit 25. When the detected voltage is a predetermined voltage, 35V here, the voltage detection unit 27 outputs a power failure detection signal to the CPU 23. When the voltage is the specified voltage, no signal is output to the CPU 23. The CPU 23 determines that a power failure has occurred based on the input of the power failure detection signal, and sends a power failure detection message to the center device 6 via the network controller 22. When the power failure detection signal is lost, a power failure recovery message is sent to the center device 6.

  With the configuration as described above, it is possible to detect the occurrence and recovery of a power failure in the communication terminal device 2 that receives power supply from the router 4 having a backup power source such as the uninterruptible power supply 9. Then, the detection result is notified to the center device 6. Further, since the communication terminal device 2 can detect a power failure and recovery using the network cable 3, no dedicated wiring for signal transmission is required.

  A specific operation of the power failure detection process in the communication terminal device 2 will be described with reference to FIG. First, when a power failure occurs, the router 4 switches the supplied voltage from a specified voltage to a predetermined voltage. The voltage detector 27 detects this voltage switching and outputs a power failure detection signal. When the power failure detection signal is input, the CPU 23 determines that a power failure has occurred (ST1). In ST2, it is confirmed whether or not a power failure detection message has been transmitted. When a power failure detection message is transmitted, the following processing is skipped and the power failure detection processing is exited. When the power failure detection message is not transmitted, the following processing is executed.

  The CPU 23 determines whether initialization communication is being performed. Since the communication with the center device 6 is still impossible when the initial setting communication is being performed, this process is exited to wait until the initial setting communication is completed (ST3). The initial setting is a setting of an IP address or the like for communicating with the center apparatus 6. The communication terminal apparatus 2 accesses the center apparatus 6 and obtains setting information from the center apparatus 6. If the initial setting is not completed, communication with the center device 6 cannot be performed. When the initial setting communication is not being performed, it is determined whether another communication with the center apparatus 6 is being performed (ST4). When not communicating, a power failure detection message is immediately transmitted to the center device 6 (ST7). Thereby, the center device 6 recognizes that a power failure has occurred on the terminal side, and performs processing corresponding to this.

  When the communication is in progress, the CPU 23 determines whether to interrupt the communication and transmit a power failure detection message (ST5). When disconnecting, the communication with the center apparatus 6 is immediately disconnected (ST6), and a power failure detection message is transmitted to the center apparatus 6 (ST7). Whether or not to disconnect during communication is preset as setting information from the center device 6 or the like, and is stored in, for example, a non-volatile memory. When disconnection is not performed during communication (ST5), the power failure detection process is temporarily exited and the process returns to the normal process (ST9). After executing the normal process, this power failure detection process is entered again, and after detecting that the communication has been completed (ST4), a power failure detection message is transmitted to the center device 6 (ST7). When a power failure detection message is transmitted, transmission of the power failure detection message is set by a flag or the like in ST8 so that the power failure detection message is not transmitted many times. In addition, you may make it the structure which resends a power failure detection message | telegram during a power failure.

  Next, when recovering from the power failure, the router 4 supplies a specified voltage, and the voltage detector 27 detects this change. As shown in FIG. 4, when the power failure detection signal from the voltage detector 27 is turned off, the CPU 23 determines that the power failure has been recovered (ST10). In ST11, it is confirmed whether or not a power recovery detection message has been transmitted. When the power recovery detection message is transmitted, the following processing is skipped and the power recovery detection processing is exited. When the power recovery detection message is not transmitted, the following processing is executed.

  The CPU 23 determines whether communication is in progress (ST12). When the communication is in progress, the power recovery detection process is temporarily exited and the process returns to the normal process (ST16). After executing the normal process, this power recovery detection process is entered again, and after the communication is completed, a power recovery detection message is transmitted to the center device 6 (ST13). When the power recovery detection message is transmitted, in ST14, the transmission completion of the power recovery detection message is set. Then, the power failure detection message is set to not transmitted (ST15), and the message can be transmitted to the center device 6 when the next power failure occurs.

  As described above, not only the communication terminal apparatus 2 but also the center apparatus 6 can recognize the occurrence of a power failure and its recovery. Therefore, by avoiding data communication during a power outage and performing data communication after recovery from the power outage, operation in an unstable communication environment can be avoided and communication can be performed efficiently. Also, when performing data communication during a power outage, the power supply from the uninterruptible power supply 9 is prolonged due to prolonged power outage, and even if communication is interrupted, it can be seen that the cause of the communication error is due to the power outage, There is no need to perform unnecessary operations such as retransmission.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention. Although a router is used as the power supply apparatus, network devices such as a LAN switch, a hub, and a modem for forming a network may be used, and network power supply is performed according to the PoE technology.

  In the above embodiment, the router having the uninterruptible power supply device is the power supply device. However, instead of this, the uninterruptible power supply device may be directly connected to the communication terminal device without using the network cable. In addition, when a network device such as a router without a power supply function and a communication terminal device are connected via a network cable and a network is already formed, a power supply device having a backup power source is installed in the network cable. Also good. As a result, the existing data communication system can be easily upgraded to cope with a power failure.

Schematic configuration diagram of a data communication system of the present invention Block diagram showing schematic configuration of communication terminal device and router Flow chart of power failure detection process Flow chart of power failure recovery processing Schematic configuration diagram of a conventional data communication system

Explanation of symbols

2 Communication terminal device 3 Network cable 4 Router 5 Communication line 6 Center device 8 Commercial power supply 9 Uninterruptible power supply device 10 Power cable 11 Communication cable

Claims (11)

A data communication system in which a communication terminal device and a center device transmit data through a network, the power supply device supplying power to the communication terminal device and having a backup power source at the time of a power failure. A data communication system characterized in that the communication terminal apparatus is notified of the occurrence of a power failure by supplying predetermined power different from normal power at times to the communication terminal apparatus. The data communication system according to claim 1, wherein the communication terminal device operates with a predetermined power during a power failure and notifies the center device of the occurrence of the power failure. The power supply device is interposed between the network and the communication terminal device to relay communication between the communication terminal device and the center device, and the communication terminal device is connected to the power supply device via a network cable, and the power supply device The data communication system according to claim 1, wherein power is supplied to the communication terminal device through the network cable. The power supply device includes an uninterruptible power supply device as a backup power supply, and the power supply device supplies electric power by switching from specified power to predetermined power according to a power failure detection signal from the uninterruptible power supply device. Item 4. The data communication system according to item 3. The data communication system according to any one of claims 1 to 4, wherein the communication terminal device includes a detector that detects the supplied power, and determines the presence or absence of a power failure based on the supplied power. 6. The data according to claim 5, wherein the power supply device supplies the specified power to the communication terminal device when the power failure is recovered, and the communication terminal device notifies the center device of the power failure recovery when it is determined that the power failure is recovered. Communications system. The data according to any one of claims 1 to 6, wherein when the communication terminal device detects occurrence or recovery of a power failure during communication with the center device, the communication terminal device notifies the center device after ending the communication. Communications system. 7. The data communication according to claim 1, wherein the communication terminal device stops communication and notifies the center device when it detects occurrence or recovery of a power failure during communication with the center device. system. 9. The data communication system according to claim 7, wherein the communication terminal device notifies the center device after completion of the initial startup when detecting the occurrence or recovery of a power failure during the initial startup. A communication terminal device of a data communication system for transmitting data through a network with a center device, which is connected to a power supply device having a backup power supply in the event of a power failure and having a communication relay function via a network cable, from the power supply device to the network A specified power is normally supplied through the cable, and a predetermined power different from the specified power is supplied in the event of a power failure, and includes a control unit that operates with the power supplied from the power supply device. A communication terminal device that determines whether or not a power failure has occurred. The communication terminal device according to claim 10, wherein the control unit notifies the center device of the occurrence of a power failure or the recovery of the power failure.

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