JP6413260B2 - Wireless communication apparatus and wireless communication system - Google Patents

Description

  The present invention relates to a wireless communication device and a wireless communication system, and for example, relates to a wireless communication system that wirelessly performs a part of communication between a data collection device and a sensor terminal.

  Conventionally, as an energy management system (BEMS: Building Environment and Energy Management System), there is one constructed by a sensor network having a group of sensor terminals for acquiring various data.

  Conventionally, a sensor terminal used in BEMS or the like is usually connected to a higher-level data collection device (hereinafter also referred to as “data logger”) using a wired cable (for example, a wired cable such as an RS485 cable), and data Sensor data is acquired by transmitting a control instruction (command) instructing data collection or the like from the logger.

  However, since the wired cable has problems such as the wiring cost and the installation work period, in the conventional BEMS, it may be necessary to make the wired cable part wireless in order to reduce the construction cost.

  In a conventional network used for BEMS, in order to wirelessly connect a wired cable connection between a data logger and a sensor terminal, a wireless base unit for relay is connected to the data logger with a wired cable, and the sensor terminal and the wireless terminal are connected. Wireless connection between the data logger and sensor terminal is realized by connecting the machine with a wired cable. However, in this method, the cable portion is simply made wireless, and if the wireless master unit fails, communication is cut off as in the case of cable disconnection, and sensor data cannot be collected.

  Therefore, as a redundancy method in a conventional wireless communication network, for example, there is a technique described in Patent Document 1. Japanese Patent Application Laid-Open No. 2004-151561 describes a method of duplexing a multi-hop transfer path without causing a radio collision in a wireless multi-hop network.

JP 2005-354626 A

  However, even when the conventional wireless communication redundancy method is applied, as described above, a part of the data logger and the sensor terminal group are wirelessly used by using the wireless master unit and the wireless slave unit for wireless relay. In some sensor networks, efficient communication may not be possible.

  For example, even when data of a control instruction (hereinafter also referred to as “command”) is transmitted from a data logger to a specific sensor terminal, a wired cable (for example, an RS485 cable or the like) based on a multipoint serial connection type interface specification is used. In communication using a wired cable, the data logger transmits all of the wireless slave units at the same time, so unnecessary radio wave transmission occurs (from the wireless master unit unrelated to the command transmission destination to the wireless slave unit). There was a problem of radio wave transmission to the machine. This is because when the above-mentioned wireless master unit and wireless slave unit are inserted where the data logger and the sensor terminal are directly connected by a wired cable, data transmission from the data logger is not simultaneous transmission. This is unavoidable.

  In particular, when wireless communication using the 920 Mhz band is performed between the wireless master device and the wireless slave device, there is a limitation on the transmission of radio waves (for example, limitation on the radio wave transmission time per hour). By repeating the above, if the radio wave transmission time limit is exceeded, there is a possibility that the radio wave cannot be used when originally communicating, which is a serious problem.

  Therefore, a wireless communication apparatus and a wireless communication system that can perform efficient radio wave transmission are desired in a wireless communication system in which a part of communication between the data collection device and the sensor terminal is wireless.

The wireless communication device according to the first aspect of the present invention includes: (1) data collection device connection means for wired connection with the data collection device; and (2) one or more children based on a connection request from a child node connected to the sensor terminal. A child node connection means for wirelessly connecting to a node; (3) a management means for acquiring and managing a sensor terminal identifier of a corresponding sensor terminal for each child node connected by the child node connection means; and (4) Instruction data acquisition means for acquiring instruction data for the center terminal sent from the data collection device; and (5) a sensor terminal as a destination of the instruction data set in the instruction data acquired by the instruction data acquisition means. If the sensor terminal identifier is a sensor terminal corresponding to the child node connected by the child node connecting means, the instruction data transmitting means for transmitting the instruction data to the child node Have a, (6) the management means, for each child node connected with said child node connection means, holds a management table registering the terminal identifier of the corresponding sensor terminal edits the management table that (7) Each of the one or more child nodes has a child node identifier for identifying the child node, and (8) the management means further includes: A sensor terminal management table in which correspondence relationships between all the child node identifiers of the one or more child nodes and the sensor terminal identifiers are registered. (9) The management unit includes the child node connection unit and the child node connection unit. If the node is wirelessly connected, the sensor terminal identifier corresponding to the child node identifier of the child node wirelessly connected is obtained by referring to the sensor terminal management table, and the node is acquired. Characterized by editing said management table by using the sensor terminal identifier.

  A wireless communication system according to a second aspect of the present invention is a wireless communication system including a plurality of parent nodes connected in a wired manner to a data collection device and a child node connected to a sensor terminal. A wireless communication device is applied.

  ADVANTAGE OF THE INVENTION According to this invention, efficient radio wave transmission can be performed in the radio | wireless communications system which makes a part of communication between a data collection device and a sensor terminal wireless.

It is the block diagram shown about the functional structure of the wireless main | base station (wireless communication apparatus) which concerns on embodiment. It is explanatory drawing shown about the structure of the data collection system using the radio | wireless communications system which concerns on embodiment. It is explanatory drawing shown about the structural example of the connection handset information table hold | maintained at the wireless main | base station which concerns on embodiment. It is explanatory drawing shown about the example of a frame structure of the command sent from the data logger which concerns on embodiment. It is explanatory drawing shown about the structural example of the sensor table hold | maintained at the wireless main | base station which concerns on embodiment. It is the block diagram shown about the functional structure of the radio | wireless subunit | mobile_unit (wireless communication apparatus) which concerns on embodiment. It is an example of a structure of the connection destination information table hold | maintained with the wireless subunit | mobile_unit which concerns on embodiment. It is the sequence diagram shown about the example of the operation | movement which a radio | wireless subunit | mobile_unit connects to a radio | wireless parent | base station in the radio | wireless communications system which concerns on embodiment. It is the sequence diagram shown about the operation example when the command is transmitted from the data logger in the radio | wireless communications system which concerns on embodiment.

(A) Main Embodiment Hereinafter, an embodiment of a wireless communication apparatus and a wireless communication system according to the present invention will be described in detail with reference to the drawings. In the following, an example will be described in which a wireless communication device operating as a parent node of the present invention is applied to a wireless master device, and a wireless communication device operating as a child node is applied to a wireless slave device.

(A-1) Configuration of Embodiment FIG. 2 is a block diagram showing an overall configuration of a sensor data collection system to which the wireless communication system 1 of this embodiment is applied.

  In the sensor data collection system 1000, a part of communication between the data logger 10 as a data collection device and the plurality of sensor terminals 40 (40-1 to 40-4) is made wireless by the wireless communication system 1. . The number of devices constituting the wireless communication system 1 is not limited, but here, one data logger 10, two wireless master devices 20 (20-1, 20-2), four wireless devices. The subunit | mobile_unit 30 (30-1 to 30-4) and the four sensor terminals 40 (40-1 to 40-4) shall be arrange | positioned.

  In the wireless communication system 1, the wireless slave devices 30 (30-1 to 30-4) respectively corresponding to the four sensor terminals 40 (40-1 to 40-4) are arranged. Note that the wireless slave units 30-1 to 30-4 and the sensor terminals 40-1 to 40-4 are connected by a wired cable C2. The specification of the wired cable C2 between the wireless slave units 30-1 to 30-4 and the sensor terminals 40-1 to 40-4 is not limited. For example, a serial connection type cable such as an RS485 cable is applied. can do.

  The sensor mounted on each sensor terminal 40 is not limited. For example, sensors such as electric power, temperature, humidity, gas concentration, and illuminance can be applied. The sensor terminal 40 is assumed to operate based on a command (data including control instruction data) sent from the data logger 10. For example, when a command instructing output of data (hereinafter referred to as “sensor data”) based on a detection result of sensor means (not shown) is supplied, the sensor terminal 40 acquires and outputs sensor data according to the command. Process. Here, the sensor data output from the sensor terminal 40 is supplied to the data logger 10 via the wireless section (wireless communication system 1).

  The data logger 10 is connected to a wired cable C1 which is a bus connection type transmission path. Each wireless master device 20 is also connected to the wired cable C1.

  In the wireless communication system 1, each wireless slave device 30 is arranged to be wirelessly communicable with both of the plurality of wireless master devices 20. Accordingly, each wireless slave device 30 is configured to select and connect any one of the communicable wireless master devices 20. As described above, in the wireless communication system 1, the wireless slave device 30 selects one of the plurality of wireless master devices 20 to be in a connectable state, so that communication in the wireless section is made redundant. .

  Although the specification (interface specification) of the wired cable C1 is not limited, for example, a cable conforming to a multipoint serial connection type interface such as RS-485 can be applied. Note that the wired cable C1 and the wired cable C2 are cables based on the same specifications and based on the interface. One end of the wired cable C1 is connected to the data logger 10, and a plurality of branches are possible. The wired cable C1 is branched for each wireless master device 20, and the wireless master device 20 is connected to each end of the branched wired cable C1.

  Although the format of the command sent from the data logger 10 is not limited, it is assumed here that the frame is configured as shown in FIG.

  FIG. 4 is a block diagram illustrating a data configuration example of a command distributed in the wireless communication system 1.

  As shown in FIG. 4, the command includes an identifier (hereinafter referred to as “unique ID”) related to the sensor terminal 40 that is the destination of the command, and data indicating the instruction content of the command (hereinafter “control instruction data”). Called).

  It is assumed that IP packets (Ethernet packets) using Ethernet (registered trademark) frames are transmitted and received in the wireless section in the wireless communication system 1. That is, it is assumed that a command transmitted from the data logger 10 is inserted (encapsulated) into an IP packet and transmitted / received in a wireless section (between the wireless master device 20 and the wireless slave device 30). Further, data such as sensor data transmitted from the sensor terminal 40 is inserted (encapsulated) into an IP packet and transmitted / received in a wireless section (between the wireless master device 20 and the wireless slave device 30). In the wireless communication system 1, a virtual IP address is also assigned to the data logger 10, and when the wireless slave unit 30 transmits data addressed to the data logger 10, an IP packet in which the IP address is set. Shall be sent. In the wireless communication system 1, for IP packets (Ethernet packets) obtained by encapsulating commands sent from the data logger 10 or sensor data sent from the sensor terminal 40, a predetermined value is set in the header information (for example, port It is assumed that a predetermined value is set in the number or protocol number), and an IP packet (Ethernet packet) in which a command or sensor data is encapsulated can be identified on the receiving side.

  As described above, the data logger 10 is wire-connected to the wireless master device 20, the wireless master device 20 is wirelessly connected to the wireless slave device 30, and the wireless slave device 30 is wired to the sensor terminal 40.

  Next, the internal configuration of the wireless master device 20 will be described with reference to FIG.

  Here, description will be given assuming that all the wireless master devices 20 have the same configuration.

  As shown in FIG. 1, the wireless master device 20 includes a command receiving unit 201, a destination analyzing unit 202, a command transmitting unit 203, a slave device connection control unit 204, a connected slave device information table 205, a wired IF unit 206, and a wireless IF unit. 207, a transmission / reception processing unit 208, and a sensor management table 209.

  The wired IF unit 206 is a network interface for connecting to the transmission path of the wired cable C1.

  The wireless IF unit 207 is a network interface for wireless connection with the wireless slave device 30. As the wireless IF unit 207, for example, various wireless LAN interfaces can be applied.

  The transmission / reception processing unit 208 performs data transmission / reception processing using the wired IF unit 206 or the wireless IF unit 207. When the wired IF unit 206 receives a command sent from the data logger 10, the transmission / reception processing unit 208 supplies the command to the command receiving unit 201. Then, the sensor terminal 40 executes a command supplied from the wireless slave device 30. For example, when the command of the sensor data response (data logger 10) based on the currently detected value is set in the command at the sensor terminal 40, the sensor terminal 40 acquires the sensor data according to the command. Then, the sensor data is returned (response to the wireless slave unit 30).

  When the transmission / reception processing unit 208 receives a packet (IP packet) in which sensor data transmitted from the wireless slave unit 30 is inserted, the transmission / reception processing unit 208 extracts the sensor data from the packet and transmits the packet data from the wired IF unit 206 (data (Send to logger 10).

  When the transmission / reception processing unit 208 detects a command transmitted from the data logger 10, the command reception unit 201 performs processing for receiving the command.

  The destination analysis unit 202 analyzes the command received by the command reception unit 201 and identifies the sensor terminal 40 (unique ID) that is the target (destination) of the command.

  The connection slave device information table 205 is information for managing the wireless slave device 30 to which the own device is connected (accommodated).

  The command transmission unit 203 performs processing to send the received command to the destination sensor terminal 40 analyzed by the destination analysis unit 202 (transfer to the wireless slave device 30 to which the sensor terminal 40 is connected). is there. Specifically, the command transmission unit 203 transmits the packet into which the command is inserted to the corresponding wireless slave unit 30 via the transmission / reception processing unit 208.

  FIG. 3 is an explanatory diagram showing a configuration example of the connection child device information table 205.

  In the connected slave unit information table 205 shown in FIG. 3, for each wireless slave unit 30, a MAC address (hereinafter also referred to as “slave unit MAC address”), an IP address (hereinafter also referred to as “slave unit IP address”), and The unique ID of the sensor terminal 40 to which each wireless slave device 30 is connected is registered.

  The slave unit connection control unit 204 performs a communication control process with the wireless slave unit 30 via the transmission / reception processing unit 208. Further, the slave unit connection control unit 204 performs registration / deletion processing of the slave unit information table 205 based on a connection request from the wireless slave unit 30 and the like. In other words, the handset connection control unit 204 manages the wireless handset 30 connected by its own device by editing the contents of the connected handset information table 205.

  FIG. 5 is an explanatory diagram showing a configuration example of the sensor management table 209.

  The sensor management table 209 manages the correspondence relationship between each wireless slave device 30 and the sensor terminal 40 in the wireless communication system 1. In other words, the sensor management table 209 manages to which wireless slave unit 30 each sensor terminal 40 is connected. In the wireless communication system 1, it is assumed that a sensor management table 209 having common contents is registered in advance in each wireless master device 20.

  In the sensor management table 209 shown in FIG. 5, the IP address is applied as it is as a slave unit identifier for identifying each wireless slave unit 30. Note that as the slave unit identifier, all digits of the IP address of the wireless slave unit 30 may be applied, or a unique identifier in the wireless communication system 1 (a source can be specified when a packet is received). If it can be used as an identifier, a part of the IP address (for example, a short address such as the lower 16 bits) may be applied. In this embodiment, when the IP address of each wireless slave unit 30 is an IPv6 system, the lower 16 bits of the IPv6 address are applied as the wireless slave unit identifier (short address) of the sensor management table 209. May be.

  Next, the internal configuration of each wireless slave unit 30 will be described with reference to FIG.

  The wireless slave device 30 includes a parent device connection control unit 301, a connection destination information table 302, a wireless IF unit 303, a wired IF unit 304, and a transmission / reception processing unit 305.

  The wireless IF unit 303 is a network interface for wireless communication with the wireless master device 20.

  The wired IF unit 304 is an interface for connecting to the sensor terminal 40.

  The transmission / reception processing unit 305 performs data transmission / reception processing using the wireless IF unit 303 or the wired IF unit 304. When the wireless IF unit 303 receives a packet (IP packet) in which the command sent from the wireless master device 20 is received, the transmission / reception processing unit 305 extracts the command inserted in the packet, and the wired IF unit The data is supplied to the sensor terminal 40 via 304. Further, when the wired IF unit 304 detects data such as sensor data output from the sensor terminal 40, the transmission / reception processing unit 305 transmits a packet in which the data is inserted from the wired IF unit 304 (data logger 10). To send).

  The connection destination information table 302 is information for managing the wireless master device 20 to which the own device is connected (accommodated).

  FIG. 7 is an explanatory diagram showing a configuration example of the connection destination information table 302.

  In the connection destination information table 302 shown in FIG. 7, connection priority, MAC address (hereinafter referred to as “parent device MAC address”), and IP address for each wireless master device 20 to which the own device can be connected (direct wireless communication is possible). (Hereinafter referred to as “master IP address”) is managed. The connection destination information table 302 illustrated in FIG. 7 indicates that the wireless master device 20 having a smaller connection priority value has a higher priority. Note that the parent device may be identified using a PAN (Personal Area Network) ID formed by the parent device instead of the MAC address.

  The base unit connection control unit 301 performs processing for performing control so as to continue the connection state (a state in which packets can be transmitted and received) with any one of the wireless base units 20 according to the connection destination information table 302.

  Here, it is assumed that each wireless slave device 30 is arranged so as to be capable of direct wireless communication with a plurality of wireless master devices 20 at the same time in a normal state (a state where no failure has occurred). This is a configuration aiming at redundancy of a communication path from each wireless slave unit 30 to the data logger 10.

  In other words, one PAN (personal area network) is formed under the control of one wireless master device 20 (a node including the wireless master device 20, the wireless slave device 30, and the sensor terminal 40). That is, in the connection destination information table 302, the priority of the connection destination PAN is managed, and the parent device connection control unit 301 performs processing for determining the connection destination PAN based on the connection destination information table 302. become.

  Here, the base unit connection control unit 301 performs communication control to continue the connection with the radio base unit 20 having the highest connection priority among those connectable with the radio base unit 20 set in the connection destination information table 302. Assumed to be performed. Specifically, when activated, the base unit connection control unit 301 tries to connect in order from the radio base unit 20 with the highest priority based on the connection destination information table 302 and connects to the connectable radio base unit 20. Then, the base unit connection control unit 301 performs connection confirmation with a confirmation response to the connected wireless base unit 20 at regular or irregular intervals, and when there is no response, the wireless base unit 20 For the wireless master device 30, it is determined that communication is impossible, and connection to the wireless master device 20 having the next highest priority is attempted. At this time, the base unit connection control unit 301 may perform control so as to perform connection with the highest priority among the connectable wireless base units 20 in the same sequence as that at the time of activation. For example, as a connection confirmation method for the wireless master device 20 performed by the master device connection control unit 301, for example, a connection confirmation process (so-called Ping) using an ICMP (Internet Control Message Protocol) command or an arbitrary message is used. A sequence for transmitting / receiving a packet for connection confirmation accompanied by a confirmation response such as an ACK request or the like may be executed.

  The specific configuration of each sensor terminal 40 is not limited, and sensors and the like applied to various sensor networks can be applied. Here, the specific format of output data such as sensor data based on detection by the sensor terminal 40 is not limited.

(A-2) Operation | movement of embodiment Next, operation | movement of the radio | wireless communications system 1 of this embodiment which has the above structures is demonstrated.

  In the following, it is assumed that the IP addresses of the wireless masters 20-1 and 20-2 are 169.123.222.111 and 169.123.222.222, respectively. The MAC addresses of the wireless master devices 20-1 and 20-2 are A1-12-34-56-78-90 and A2-12-34-56-78-91, respectively. Further, it is assumed that the unique IDs of the sensor terminals 40-1 and 40-2 are 001 and 002, respectively. Furthermore, here, it is assumed that the content of the connection destination information table 302 of the wireless slave device 30-1 is the content of FIG.

  Therefore, the sensor terminal 40-1 (unique ID: 001) is connected under the wireless slave device 30-1. The wireless slave device 30-1 is connected to either the wireless master device 20-1 or 20-2 based on the contents of the connection destination information table 302. As shown in FIG. 7, in the connection destination information table 302 of the wireless slave device 30-1, the wireless master device 20-1 is set to the highest connection priority (1), and the wireless master device 20-2 is set to the connection priority (2) having the next highest priority.

(A-2-1) Configuration Operation of PAN First, the operation of the PAN formed under each wireless master device 20 will be described with reference to the sequence diagram of FIG.

  Here, the operation centering on the wireless slave device 30-1 will be described.

  Here, it is assumed that the wired IF unit 304 of the wireless slave device 30-1 is connected to the sensor terminal 40-1 and is in a connected state (S101). Although a detailed description of the connection sequence between the wireless slave device 30-1 and the sensor terminal 40-1 is omitted here, various serial interface connection sequences can be applied.

  Then, the parent device connection control unit 301 of the wireless slave device 30-1 makes a connection request to the wireless parent device 20-1 having the highest priority based on the connection destination information table 302 (see FIG. 7 described above) (S102). ).

  Next, the slave connection control unit 204 of the wireless master device 20-1 transmits an acknowledgment (ACK) in response to the connection request from the wireless slave device 30-1 (S103), and then with the wireless slave device 30-1. It is assumed that the connection state with the wireless master device 20-1 has been established (S104).

  Note that the connection sequence between the wireless slave device 30-1 and the wireless master device 20-1 is not limited to the example in FIG. 8, and includes other processing (for example, authentication processing, encryption processing, etc.). Of course, it may be possible to make it unclear.

  Next, the slave connection control unit 204 of the wireless master device 20-1 stores information on the newly connected wireless slave device 30-1 (slave device MAC address: A1-12-34-) in the connection slave device information table 205. 56-78-90, slave device IP address: 169.123.111.111, unique ID: 001) is additionally updated (S105).

  When receiving the connection request packet (IP packet) from the wireless slave device 30-1, the slave device connection control unit 204 of the wireless master device 20-1 confirms the transmission source of the header of the packet, The wireless slave device identifier (IP address) of the wireless slave device 30-1 as the connection request source is acquired. And the subunit | mobile_unit connection control part 204 of the radio | wireless main | base station 20-1 collates the acquired radio | wireless subunit | mobile_unit identifier with the sensor management table 209, and is connected to the radio | wireless subunit | mobile_unit 30-1 of a connection request origin. The unique ID of the terminal 40 can be acquired, and the connected handset information table 205 can be updated as described above.

  By the operation as described above, the wireless slave device 30-1 can be connected to the PAN managed by the wireless master device 20-1. After that, the wireless slave device 30-1 (master device connection control unit 301) performs connection confirmation with a confirmation response to the connected wireless master device 20-1 at regular or irregular intervals. When there is no response (for example, when there is no response for a predetermined time or a predetermined number of times), it is determined that communication is impossible for the wireless master device 20-1, and then the wireless master device 20-2 with the next highest priority is connected. The process (the process of the sequence similar to the above-mentioned FIG. 8) which tries is performed.

  On the other hand, the wireless master device 20-1 (slave device connection control unit 204) also performs connection confirmation processing with a confirmation response to the wireless slave device 30-1 at regular or irregular intervals. If there is no response (for example, when there is no response for a predetermined time or a predetermined number of times), it is assumed that the wireless master device 20-1 no longer exists under the management (from the connected slave device information table 205 to the wireless master device 20-1). The process of canceling the connection is performed by deleting the information.

  Next, a process in which a command requesting sensor data is transmitted from the data logger 10 to the sensor terminal 40 and the sensor terminal 40 responds with the sensor data in response thereto will be described with reference to the sequence diagram of FIG. .

  FIG. 9 shows an example where a command requesting sensor data is transmitted from the data logger 10 to the sensor terminal 40-1 as a destination.

  Here, the sensor terminal 40-1 will be described as belonging to the wireless slave device 30-1. The wireless slave device 30-1 will be described as belonging to the PAN under the control of the wireless master device 20-1. Furthermore, description will be made assuming that the contents of the connection slave device information table 205 of the wireless master device 20-1 are as shown in FIG.

  First, the data logger 10 generates a command (command requesting a response to sensor data) in which “001” that is the unique ID of the sensor terminal 40-1 is set as the unique ID of the destination, and the command signal ( Assume that the frame is sent onto the wired cable C1 (S201).

  In the wireless master device 20-1, the command reception unit 201 acquires the command, and the destination analysis unit 202 analyzes the unique ID of the destination of the command (S202).

  In the wireless master device 20-1, the command transmission unit 203 determines whether the destination (unique ID) of the analyzed command is the sensor terminal 40 under its own device based on the connection slave device information table 205. It is judged (S203).

  If the destination of the command is under its control, the command transmission unit 203 sends the data of the command to the wireless device that accommodates the sensor terminal 40 that is the destination of the command according to the connection device information table 205. To the machine 30. Here, since the unique ID of the destination of the command is “001”, the command transmission unit 203 generates a packet for transmitting the data of the command to the wireless slave device 30-1 according to the connection slave device information table 205. (S204).

  When it is determined in step S203 described above that the destination of the command is not under the control of the own device, the command transmission unit 203 discards the data of the command (S209) and ends the process.

  In the wireless slave device 30-1, when the wireless IF unit 303 receives the packet into which the command is inserted, the transmission / reception processing unit 305 extracts the command from the packet and sends the command to the sensor terminal 40-1. Supply (S205).

  When the command is supplied, the sensor terminal 40 starts executing the command (S206). Here, it is assumed that the sensor terminal 40 performs a process of acquiring sensor data based on the detection of the sensor according to the supplied command and returning it to the wireless slave device 30-1 (S207). The command that can be executed by the sensor terminal 40 is not limited to the response of the sensor data, and various sensor-related processes such as a process of simply holding the sensor data and a process of initializing the sensor can be applied. it can. At this time, the sensor terminal 40 adds a unique ID of its own device to the generated sensor data and responds.

  Then, the command transmission unit 304 of the wireless slave device 30-1 generates a packet in which the sensor data acquired from the sensor terminal 40 is inserted, and transmits the packet to the data logger 10 (the wireless slave device 30 serving as a master station). (S208).

  Then, the wireless master device 20-1 (transmission / reception processing unit 208) performs processing for transferring the received packet (packet in which sensor data is inserted) to the data logger 10 (S209).

  As described above, in the wireless communication system 1, the command from the data logger 10 is supplied to the sensor terminal 40-1, and the sensor data generated by the sensor terminal 40-1 is supplied to the data logger 10.

(A-3) Effects of Embodiment According to this embodiment, the following effects can be achieved.

  In the wireless communication system 1, even if a plurality of wireless master devices 20 are connected to the data logger 10 by wired connection (bus connection) and operated, radio waves are transmitted to the wireless slave device 30 serving as a specific destination in units of commands. Only one wireless master device 20 can be used to suppress wasteful radio wave transmission and realize efficient wireless communication. In addition, by suppressing the transmission of radio waves from the wireless master device 20, there is an effect of preventing problems such as radio wave interference and collision with wireless devices in the same frequency band used in the vicinity.

  In other words, since the data logger 10 and the sensor terminal 40 are originally connected by a serial interface using a wired cable such as RS485, the command originally transmitted from the data logger 10 is a broadcast transmission addressed to all the sensor terminals 40. Although it is data, by applying the wireless communication system 1, it is possible to suppress the wireless master device 20 from sending unnecessary radio waves to the wireless slave device 30.

(B) Other Embodiments The present invention is not limited to the above-described embodiments, and may include modified embodiments as exemplified below.

(B-1) In the wireless slave device 30 of the above-described embodiment, if any one of the plurality of wireless master devices 20 is selected to be connectable and a failure occurs in the connected wireless master device 20, communication is performed. The wireless master device 20 having the highest priority among the possible wireless master devices 20 is connected to make communication redundant. However, such a redundant configuration may be omitted. For example, in the wireless slave device 30, only one wireless master device 20 to be connected may be registered instead of the connection destination information table 302.

(B-2) In the above embodiment, in each wireless slave device 30, the wireless master device 20 to be connected is determined according to the preset connection destination information table 302, but the connection destination information table 302 is omitted. Then, the wireless master device 20 that can be connected may be selected and connected. For example, the wireless master device 20 to which the wireless slave device 30 can be connected is searched, and an arbitrary one is selected from the detected wireless master devices 20 (for example, randomly selected or one having the best communication state is selected. Or may be connected.

  DESCRIPTION OF SYMBOLS 1000 ... Sensor data collection system, 1 ... Wireless communication system, 10 ... Data logger, 20, 20-1, 20-2 ... Wireless main | base station, 201 ... Command receiving part, 202 ... Destination analysis part, 203 ... Command transmission part, 204 ... Slave device connection control unit, 205 ... Connection slave device information table, 206 ... Wired IF unit, 207 ... Wireless IF unit, 208 ... Transmission / reception processing unit, 209 ... Sensor management table, 30-1 to 30-4, 30 ... Wireless slave unit 301 ... Master unit connection control unit 302 ... Connection destination information table 303 ... Wireless IF unit 304 304 Wired IF unit 305 Transmission / reception processing unit 40, 40-1 to 40-4 Sensor terminal C1, C2 ... Wired cables.

Claims (4)

Data collection device connection means for wired connection with the data collection device;
A child node connection means for wirelessly connecting to one or more child nodes based on a connection request from a child node connected to the sensor terminal;
Management means for acquiring and managing the sensor terminal identifier of the corresponding sensor terminal for each child node connected by the child node connection means,
Instruction data acquisition means for acquiring instruction data for the sensor terminal sent from the data collection device;
When the sensor terminal identifier of the sensor terminal that is the destination of the instruction data set in the instruction data acquired by the instruction data acquisition unit is a sensor terminal corresponding to the child node connected by the child node connection unit, Instruction data transmission means for transmitting the instruction data to the child node ;
The management means maintains a management table in which terminal identifiers of corresponding sensor terminals are registered for each child node connected by the child node connection means, and supports each child node by editing the management table. Manage sensor terminals
Each of the one or more child nodes has a child node identifier identifying the child node;
The management means further includes a sensor terminal management table in which correspondence relationships between all the child node identifiers of the one or more child nodes and the sensor terminal identifier are registered,
If the child node connection means wirelessly connects the child node, the management means acquires the sensor terminal identifier corresponding to the child node identifier of the child node wirelessly connected with reference to the sensor terminal management table And editing the management table using the acquired sensor terminal identifier . The child node connection means confirms connection with the connected child node at regular or irregular intervals, and when it is determined that the connection cannot be confirmed, stops the connection with the child node,
The wireless communication apparatus according to claim 1 , wherein the management unit deletes information related to a child node whose connection has been canceled by the child node connection unit from the management table. In the instruction data transmission unit, the sensor terminal identifier of the sensor terminal that is the destination of the instruction data set in the instruction data acquired by the instruction data acquisition unit corresponds to the child node connected by the child node connection unit. The wireless communication apparatus according to claim 1 or 2 , wherein if the sensor terminal is not a sensor terminal, the instruction data is discarded without being transmitted. In a wireless communication system comprising a plurality of parent nodes connected in a wired manner to a data collection device and a child node connected to a sensor terminal,
A wireless communication system, wherein the wireless communication device according to claim 1 is applied as the parent node.

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