Communication system, communication method, and communication program

Abstract

To provide a communication system, a communication method, and a communication program capable of installing a large number of slave stations while ensuring high-speed responsiveness of communication between a master station and a slave station.SOLUTION: In a communication system, each of a plurality of slave stations includes an allocation processing unit that is associated with any one of a plurality of master stations and respectively assigns the plurality of master stations to a plurality of time segments obtained by time-dividing the predetermined cycle in a predetermined channel, and a communication processing unit that causes the master station and the plurality of slave stations associated with the master station to communicate in each of the plurality of time segments within the time segment.SELECTED DRAWING: Figure 8

Description

Technical Field

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[0001] The present invention relates to a communication system, a communication method, and a communication program.

Background Art

[0002] Conventionally, a communication method (TDMA; Time Division Multiple Access) is known in which one master station (also referred to as a controller, host, etc.) occupies one channel and sequentially communicates with a plurality of slave stations (also referred to as slaves) assigned to the master station in a time division manner. For each slave station, a certain period immediately after receiving communication (transmission data) from the master station is assigned as the time during which communication with the host is possible.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The object of the present invention is to provide a communication system, a communication method, and a communication program that enable the installation of a large number of slave stations while ensuring high-speed response of communication between the master station and slave stations. [Means for solving the problem]

[0007] A communication system according to an embodiment of the present invention is a communication system in which a plurality of master stations and a plurality of slave stations perform wireless communication at a predetermined period, wherein each of the plurality of slave stations is associated with one of the plurality of master stations, and comprises an assignment processing unit that assigns each of the plurality of master stations to each of a plurality of time divisions obtained by dividing the predetermined period into time segments on a predetermined channel, and a communication processing unit that causes the master station and the plurality of slave stations associated with the master station to communicate within each of the plurality of time segments.

[0008] A communication method according to an embodiment of the present invention is a communication method in which a plurality of master stations and a plurality of slave stations perform wireless communication at a predetermined period, wherein each of the plurality of slave stations is associated with one of the plurality of master stations, and one or more processors perform an assignment step of assigning each of the plurality of master stations to each of a plurality of time divisions obtained by dividing the predetermined period in a predetermined channel, and a communication step of causing the master station and the plurality of slave stations associated with the master station to communicate within each of the plurality of time divisions.

[0009] A communication program according to an embodiment of the present invention is a communication program in which a plurality of master stations and a plurality of slave stations perform wireless communication at a predetermined period, wherein each of the plurality of slave stations is associated with one of the plurality of master stations, and the program causes one or more processors to execute an assignment step of assigning each of the plurality of master stations to each of a plurality of time divisions obtained by dividing the predetermined period in a predetermined channel, and a communication step of causing the master station and the plurality of slave stations associated with the master station to communicate within each of the plurality of time divisions. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a communication system, a communication method, and a communication program that enable the installation of a large number of slave stations while ensuring high-speed response of communication between the master station and slave stations. [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 is a functional block diagram showing a schematic configuration of a communication system according to an embodiment of the present invention. [Figure 2] Figure 2 is an external view of a storage shelf according to an embodiment of the present invention. [Figure 3] Figure 3 shows the configuration of tags installed in a storage shelf according to an embodiment of the present invention. [Figure 4] Figure 4 shows an example of tag information stored in the storage unit of a communication system according to an embodiment of the present invention. [Figure 5] Figure 5 shows an example of related information stored in the storage unit of a communication system according to an embodiment of the present invention. [Figure 6] Figure 6 is a diagram showing the correspondence between the controller and the tag according to an embodiment of the present invention. [Figure 7] Figure 7 shows an example of a time division to which a controller according to an embodiment of the present invention is assigned. [Figure 8] Figure 8 shows a specific example of a communication method according to an embodiment of the present invention. [Figure 9] FIG. 9 is a diagram showing a specific example of a communication method according to an embodiment of the present invention. [Figure 10] FIG. 10 is a flowchart for explaining an example of the procedure of communication processing executed in a communication system according to an embodiment of the present invention. [Figure 11] FIG. 11 is a diagram showing the correspondence relationship between a controller and a communication area according to an embodiment of the present invention. [Figure 12] FIG. 12 is a diagram showing a state in which each of a plurality of controllers according to an embodiment of the present invention is assigned to a channel and a time slot.

Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Note that the following embodiments are an example of embodying the present invention and do not have the character of limiting the technical scope of the present invention.

[0013] FIG. 1 is a functional block diagram showing a schematic configuration of a communication system 10 according to an embodiment of the present invention.

[0014] The communication system 10 includes a management server 1, a controller 2, and a tag Tg. The communication system 10 is introduced, for example, into a work site (such as a factory or a warehouse) where an operator picks a target article from a storage shelf 3 (see FIG. 2) that stores articles. The articles are not particularly limited and include articles in various fields such as parts, retail products, drugs, books, documents, sundries, etc. In the present embodiment, as an example of the articles, parts used in the assembly work of a predetermined product (such as a vehicle or an electric appliance) are taken as an example. That is, the communication system 10 in the present embodiment is introduced into a facility F1 (such as a factory) where an operator picks a target part from a storage shelf 3 that stores parts.

[0015] The management server 1 and controller 2 are connected to each other via network N1. Network N1 is a communication network such as the Internet, LAN, WAN, or public telephone line. Controller 2 and tag Tg are connected by this communication method using radio waves. Tag Tg is installed in each storage shelf 31 of storage shelf 3 (see Figure 2). As shown in Figure 3, tag Tg includes a display unit (LCD) that displays the part name, etc., a lamp button B1 that lights up, blinks, and turns off in multiple colors, and a communication unit (not shown) that communicates with controller 2. Lamp button B1 also has a button function as a user interface. Tag Tg can display predetermined information on the display unit or light up or turn off lamp button B1 according to commands (transmitted data) from controller 2. For example, an operator picks a part from storage shelf 31 where a tag Tg with the lamp button B1 lit is installed. Tag Tg notifies controller 2 that lamp button B1 has been pressed using this communication method, and controller 2 notifies management server 1 of this. If the management server 1 confirms that tag Tg corresponds to the correct part, it uses this communication method to notify the controller 2 of a signal to the tag Tg corresponding to the next part to be picked, causing lamp button B1 to blink at a predetermined interval. Figure 3 shows the state where tag 1 is lit. The management server 1 controls each controller 2 collectively and outputs a transmission instruction (such as a command to light up tag Tg) to the designated controller 2 based on the information of the picking target.

[0016] Multiple storage shelves 3 are arranged within facility F1. Multiple controllers 2 are installed distributed throughout facility F1, and these multiple controllers 2 communicate with the tags Tg on the multiple storage shelves 3 located within facility F1. In this way, the communication system 10 constructs the picking system for facility F1 by controlling the multiple tags Tg located within facility F1 using multiple controllers 2. Specifically, the communication system 10 is a system that manages radio communication between the multiple controllers 2 and the multiple tags Tg to occur at predetermined intervals.

[0017] The management server 1 functions as a mediation station that manages and controls the controller 2. The controller 2 functions as a host device, and the tag Tg functions as a slave device. The controller 2 is an example of the master station of the present invention, and the tag Tg is an example of the slave station of the present invention.

[0018] [Management Server 1] As shown in FIG. 1, the management server 1 includes a control unit 11, a storage unit 12, an operation display unit 13, a communication unit 14, and the like. The management server 1 may be an information processing device such as a personal computer. Further, the management server 1 may be composed of a cloud server.

[0019] The communication unit 14 connects the management server 1 to the network N1 by wire or wirelessly, and executes data communication with the controller 2 via the network N1 according to a predetermined communication protocol.

[0020] The operation display unit 13 is a user interface including a display unit such as a liquid crystal display or an organic EL display for displaying various information, and an operation unit such as a touch panel, a mouse, or a keyboard for receiving operations.

[0021] The storage unit 12 is a non-volatile storage unit such as an HDD (Hard Disk Drive), an SSD (Solid State Drive), or a flash memory for storing various information. Data such as tag information D1 and related information D2 is stored in the storage unit 12.

[0022] Figure 4 shows an example of tag information D1. Tag information D1 registers information about all tags Tg placed in facility F1. Specifically, tag information D1 includes information such as tag ID, location information, and part name. The tag ID is the identification information of tag Tg. The location information is the location information of the place where tag Tg is installed, such as the location of storage shelf 3, the shelf number of storage shelf 3 (storage shelf 31), and the coordinates of facility F1 on a map. The part name is the name of the part stored in storage shelf 31 where tag Tg is installed.

[0023] Tag information D1 is registered, for example, by the administrator of facility F1. Tag information D1 may also be stored on a server different from management server 1.

[0024] Figure 5 shows an example of related information D2. Related information D2 is information that identifies the tag Tg associated with each of the multiple controllers 2. Specifically, related information D2 includes information such as controller ID and tag ID. The controller ID is the identification information of controller 2, and the tag ID is the identification information of tag Tg. In reality, each controller 2 is associated with the tag Tg that provides the most stable communication, so the IDs of tag Tg are random and have no regularity.

[0025] As shown in Figure 6, multiple tags Tg are associated with one controller 2. Each controller 2 can communicate with multiple tags Tg, and each tag Tg can communicate with one controller 2. For example, controller A can communicate with tags Tg in communication area AR1, and controller B can communicate with tags Tg in communication area AR2. In practice, to ensure sufficient communication stability, a single tag Tg is often located within the communication area AR of multiple controllers 2, as shown in Figure 11. Each tag Tg is associated with the controller 2 that provides the most stable communication among the multiple controllers 2, but this area experiences radio interference from the multiple controllers 2, as shown in Figure 11. In this embodiment, five controllers 2 (controllers A to E) are configured to cover the entire work area of ​​facility F1 and enable communication with all tags Tg within facility F1. Related information D2 is registered by the processing of the control unit 11 (described later).

[0026] Furthermore, the storage unit 12 may store picking information, including the order in which parts are picked. For each part to be picked, the picking information is registered with associated information such as tag ID, location information, and picking status. The management server 1 registers the information to be picked in the picking information based on the picking instructions. The management server 1 may obtain the picking instructions from a server that manages the product manufacturing process, or it may generate the picking information based on the manufacturing process stored in the storage unit 12.

[0027] Furthermore, the storage unit 12 stores control programs, such as communication programs, that cause the control unit 11 to execute the communication processing described later (see Figure 10). For example, the communication program is non-temporarily recorded on a computer-readable recording medium such as a CD or DVD, and is read by a reading device (not shown), such as a CD drive or DVD drive, which is electrically connected to the management server 1, and stored in the storage unit 12.

[0028] The control unit 11 includes control equipment such as a CPU. The CPU is a processor that performs various arithmetic operations. The control unit 11 controls the management server 1 by executing various control programs pre-stored in the storage unit 12 using the CPU.

[0029] Specifically, the control unit 11 includes various processing units such as the related processing unit 111, the allocation processing unit 112, and the communication processing unit 113. The control unit 11 functions as these various processing units by executing various processes according to the communication program using the CPU. Some or all of the processing units included in the control unit 11 may be composed of electronic circuits. The communication program may be a program that causes multiple processors to function as these various processing units.

[0030] The association processing unit 111 associates each of the multiple tags Tg with one of the multiple controllers 2.

[0031] For example, as shown in Figure 5, the association processing unit 111 associates multiple tags Tg with tag IDs "tg0001 to tg0100" located in communication area AR1 with controller A, controller ID "c0001", located in communication area AR1. The association processing unit 111 also associates multiple tags Tg with tag IDs "tg0101 to tg0200" located in communication area AR2 with controller B, controller ID "c0002", located in communication area AR2. Furthermore, the association processing unit 111 associates multiple tags Tg with tag IDs "tg0201 to tg0300" located in communication area AR3 with controller C, controller ID "c0003", located in communication area AR3. Furthermore, the related processing unit 111 associates multiple tags Tg with tag IDs "tg0301 to tg0400" located in communication area AR4 with controller D with controller ID "c0004" located in communication area AR4. Also, the related processing unit 111 associates multiple tags Tg with tag IDs "tg0401 to tg0500" located in communication area AR5 with controller E with controller ID "c0005" located in communication area AR5.

[0032] The above association is the result of associating each tag Tg with the controller 2 that provides the most stable communication, and then assigning numbers as appropriate. In this invention, each of the multiple slave stations may be pre-associated with one of the multiple master stations.

[0033] The association processing unit 111 registers information about the associated controller 2 and tag Tg in the association information D2 (see Figure 5).

[0034] The allocation processing unit 112 assigns each of the multiple controllers 2 to one of several time slots (time divisions) obtained by dividing a predetermined period within a predetermined channel. For example, as shown in Figure 7, if the period is "C1", the period C1 is divided into multiple time slots. Here, the period C1 is divided into five time slots t1 to t5. Also, here it is assumed that one predetermined channel CH1 is used. A number of controllers 2 capable of communicating with multiple tags Tg within a predetermined period are assigned to channel CH1. For example, the allocation processing unit 112 assigns controller A to the first time slot t1, controller B to the second time slot t2, controller C to the third time slot t3, controller D to the fourth time slot t4, and controller E to the fifth time slot t5.

[0035] The allocation processing unit 112 assigns controllers A to E to time segments t1 to t5 in order for each period C1.

[0036] The communication processing unit 113 causes the controller 2 and the multiple tags Tg associated with the controller 2 by the related processing unit 111 to communicate within each of the multiple time segments. A specific example of the communication method will be explained with reference to Figure 8.

[0037] In the example shown in Figure 8, the period C1 in channel CH1 is set to "200ms", and the time width of each time segment t1 to t5 is set to "40ms". The communication processing unit 113 outputs a transmission instruction to the controller A for transmission data in the first time segment t1 of period C1. The transmission data is, for example, a beacon.

[0038] Here, as shown in Figure 9, the transmitted data includes command information (command information) that causes a tag Tg to execute a predetermined process, and identification information (destination information) that identifies the tag Tg that will execute the command. Specifically, the transmitted data includes destination information for each of a predetermined number of tags Tg, and command information that causes each of the predetermined number of tags Tg to execute a predetermined command. For example, Figure 9 shows an example of transmitted data transmitted by controller A. The communication processing unit 113 identifies five tags Tg (see Figure 4) associated with the five parts to be picked from among a plurality of tags Tg (see Figure 5) associated with controller A, and outputs a transmission instruction to controller A for transmitted data that includes the identified five tags 1 to 5 as destinations.

[0039] In other words, the communication processing unit 113 causes controller A to transmit data to a predetermined number of tags Tg among a plurality of tags Tg associated with controller A. Controller A also transmits the transmission data to a predetermined number of tags Tg that can communicate with controller A within a time interval.

[0040] When Controller A receives the transmission instruction from Management Server 1, it transmits the transmission data (see Figure 9) to all tags Tg (see Figure 5) associated with Controller A in the first time segment t1 (see Figure 8).

[0041] Each tag Tg associated with controller A, upon receiving the transmission data, checks the destination included in the transmission data and executes a predetermined process if it contains a command addressed to itself. For example, if tag 1 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3). Tag 1 also sends a response (acknowledgment) to controller A when it executes the command. Similarly, each of tags 2 to 5, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller A because it contains a command addressed to itself. Controller A receives responses from each of tags 1 to 5 (see Figure 9). At this time, tags 1 to 5 transmit appropriately at timings that do not conflict with each other, depending on the position of the command addressed to them in the transmission data. In this embodiment, each tag Tg sends an acknowledgment of the same size in the order in which the commands were found, and a time interval that takes into account the time required for each acknowledgment transmission and a predetermined margin is added to prevent the respective acknowledgment signals from colliding.

[0042] Furthermore, in this embodiment, the design ensures that after all five units have sent acknowledgments within the time segment, there is remaining tag data reception period R1 (Figure 9). When the button function of the lamp is pressed, the tag Tg transmits using the CSMA / CA method during the subsequent tag data reception period R1. The tag data reception period R1 shown in Figure 9 is the uplink period from tag Tg to controller 2 using the CSMA / CA method.

[0043] Furthermore, the aforementioned confirmation response is not limited to button press information; if other user interfaces are available, it may also be the content of those operations. Additionally, if the tag Tg has a sensor function, it may be configured to transmit a response spontaneously when the measured value meets predetermined conditions.

[0044] Controller A transmits the transmission data to tags 1-5 in the first time segment t1 (40ms) of period C1 (200ms). Once the execution of the commands for tags 1-5 is complete, the communication processing unit 113 outputs a transmission instruction to controller B for the transmission data in the next second time segment t2 of period C1 (200ms) (see Figure 8). The transmission data includes the destinations and commands for tags 6-10.

[0045] Each tag Tg associated with controller B, upon receiving the transmission data, checks the destination included in the transmission data and executes a predetermined process if it contains a command addressed to itself. For example, if tag 6 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3) because it contains a command addressed to itself. Tag 6 also sends a response (acknowledgment) to controller B when it executes the command. Similarly, each of tags 7 to 10, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller B because it contains a command addressed to itself. Controller B receives responses from each of tags 6 to 10.

[0046] When controller B transmits the transmission data to tags 6-10 in the second time segment t2 (40ms) of period C1 (200ms), and the execution of the commands for tags 6-10 is completed, the communication processing unit 113 outputs a transmission instruction to controller C in the next third time segment t3 of period C1 (200ms). The transmission data includes the destinations and commands for tags 11-15 (see Figure 8).

[0047] Each tag Tg associated with controller C, upon receiving the transmission data, checks the destination included in the transmission data and executes a predetermined process if it contains a command addressed to itself. For example, if tag 11 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3) because it contains a command addressed to itself. Tag 11 also sends a response (acknowledgment) to controller C when it executes the command. Similarly, each of tags 12 to 15, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller C because it contains a command addressed to itself. Controller C receives responses from each of tags 11 to 15 (see Figure 8).

[0048] Controller C transmits the transmission data to tags 11-15 in the third time segment t3 (40ms) of period C1 (200ms). Once the execution of the commands for tags 11-15 is complete, the communication processing unit 113 outputs a transmission instruction to controller D for the transmission data in the next fourth time segment t4 of period C1 (200ms). The transmission data includes the destinations and commands for tags 16-20.

[0049] Each tag Tg associated with controller D, upon receiving the transmission data, checks the destination included in the transmission data and executes a predetermined process if it contains a command addressed to itself. For example, if tag 16 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3) because it contains a command addressed to itself. Tag 16 also sends a response (acknowledgment) to controller D when it has executed the command. Similarly, each of tags 17 to 20, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller D because it contains a command addressed to itself. Controller D receives responses from each of tags 16 to 20 (see Figure 8).

[0050] When controller D transmits the transmission data to tags 16-20 in the fourth time segment t4 (40ms) of period C1 (200ms), and the execution of the commands on tags 16-20 is completed, communication processing unit 113 outputs a transmission instruction to controller E in the next fifth time segment t5 of period C1 (200ms). The transmission data includes the destinations and commands for tags 21-25.

[0051] Each tag Tg associated with controller E, upon receiving the transmission data, checks the destination included in the transmission data and performs a predetermined process if it contains a command addressed to itself. For example, if tag 21 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3) because it contains a command addressed to itself. Tag 21 also sends a response (acknowledgment) to controller E when it executes the command. Similarly, each of tags 22 to 25, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller E because it contains a command addressed to itself. Controller E receives responses from each of tags 21 to 25 (see Figure 8).

[0052] When controller E transmits the transmission data to tags 21-25 in the fifth time segment t5 (40ms) of period C1 (200ms), and the execution of the commands on tags 21-25 is completed, communication processing unit 113 outputs a transmission instruction to controller A again in the first time segment t1 of the next period C1 (200ms). The transmission data includes the destinations and commands for tags 1-5.

[0053] Each tag Tg associated with controller A, upon receiving the transmission data, checks the destination included in the transmission data and executes a predetermined process if it contains a command addressed to itself. For example, if tag 1 receives the transmission data containing a command addressed to itself to turn on lamp button B1 (see Figure 3), it turns on lamp button B1 (see Figure 3) because it contains a command addressed to itself. Tag 1 also sends a response (acknowledgment) to controller A when it executes the command. Similarly, each of tags 2 to 5, upon receiving the transmission data, turns on lamp button B1 (see Figure 3) and sends a response (acknowledgment) to controller A because it contains a command addressed to itself. Controller A receives responses from each of tags 1 to 5 (see Figure 8).

[0054] As described above, the communication processing unit 113 causes the controller 2 and the multiple tags Tg associated with the controller 2 to communicate within each of the multiple time segments. The communication processing unit 113 also outputs transmission instructions for the transmission data to each of the multiple controllers 2 in the order of the time segments. As a result, for example, each of the controllers A to E communicates with the tags Tg controlled by each controller in the order of time segments t1 to t5.

[0055] For example, after controller A transmits the transmission data to five tags 1 to 5 of the multiple tags Tg associated with controller A in the first time segment t1, controller B transmits the transmission data to five tags 6 to 10 of the multiple tags Tg associated with controller B in the second time segment t2 following the first time segment t1.

[0056] Furthermore, in the first time segment t1, controller A transmits the transmission data to tags 1 to 5, and after controller A receives responses from tags 1 to 5, controller B transmits the transmission data to tags 6 to 10 in the second time segment t2.

[0057] Here, the control unit 11 executes a process to synchronize (time synchronize) the management server 1 and each controller. Also, each controller 2 executes a process to synchronize (time synchronize) with the corresponding tag Tg. As a result, each controller 2 sends transmission data to the tag Tg at a predetermined period (e.g., 200ms), and each tag Tg receives the transmission data at a predetermined period (e.g., 200ms). For example, each tag Tg starts up in accordance with the time of reception of the transmission data and starts receiving the transmission data at that reception time. Also, each tag Tg completes the reception process at the time when the transmission of the transmission data is completed by the controller 2, and performs time synchronization after the completion of the reception process. Each tag Tg sets a timer and waits (power save) until the time of reception of the next transmission data.

[0058] Time synchronization between the controllers 2 may be performed autonomously, for example, using the IEEE 1588 Precision Time Protocol. Alternatively, the communication processing unit 113 may notify each controller 2 of the period C1 and time segments t1 to t5, and control each controller 2 to communicate at the timings shown in Figure 7.

[0059] [Communication Processing] The following describes an example of the communication processing procedure performed in the communication system 10, with reference to Figure 10.

[0060] Furthermore, the present invention can be understood as an invention of a communication method that performs one or more steps included in the communication process, and the one or more steps included in the communication process described herein may be omitted as appropriate. In addition, the execution order of each step in the communication process may differ to the extent that similar effects are produced. Moreover, although the case in which each step in the communication process is executed by the management server 1 and the controller 2 is described here as an example, a communication method in which multiple processors distribute and execute each step in the communication process can also be considered as another embodiment.

[0061] Here, we will explain using the communication method shown in Figures 8 and 9 above as an example. The control unit 11 of the management server 1 uses a predetermined channel CH1 to output transmission instructions for transmission data (see Figure 8) to each of the controllers A to E that are assigned to each of the five time divisions t1 to t5 (40ms each) obtained by time-dividing a predetermined period (200ms).

[0062] First, when the first cycle (N=1) begins (S1), in step S2, the control unit 11 determines whether or not the first time segment t1 has started. If the first time segment t1 has started (S2: Yes), in step S3, the control unit 11 outputs a transmission instruction for the transmission data to the controller A. When the controller A receives the transmission instruction, it sends the transmission data, which includes the tags Tg (e.g., tags 1 to 5) that will execute the command, to all tags Tg associated with the controller A (see Figure 5).

[0063] Next, in step S4, the control unit 11 determines whether or not it has received a response (acknowledgment) from tag Tg. For example, when tags 1 to 5 receive the transmission data, execute a command (lighting command), and send a response to controller A, controller A sends the received response to management server 1. As a result, the control unit 11 of management server 1 receives the response. When the control unit 11 receives the response (S4: Yes), the process moves to step S5.

[0064] In step S5, the control unit 11 determines whether the second time segment t2 has started. If the second time segment t2 has started (S5: Yes), in step S6, the control unit 11 outputs a transmission instruction for the transmission data to the controller B. When the controller B receives the transmission instruction, it sends the transmission data, which includes the tags Tg (e.g., tags 6 to 10) that will execute the command, to all tags Tg associated with the controller B (see Figure 5).

[0065] Next, in step S7, the control unit 11 determines whether or not it has received a response from tag Tg. For example, when tags 6 to 10 receive the transmission data, execute a command (lighting command), and send a response to controller B, controller B sends the received response to management server 1. As a result, the control unit 11 of management server 1 receives the response. If the control unit 11 receives the response (S7: Yes), the process proceeds to step S8.

[0066] In step S8, the control unit 11 determines whether the third time segment t3 has started. If the third time segment t3 has started (S8: Yes), in step S9, the control unit 11 outputs a transmission instruction to the controller C for the transmission data. When the controller C receives the transmission instruction, it sends the transmission data, which includes the tags Tg (e.g., tags 11-15) that will execute the command, to all tags Tg associated with the controller C (see Figure 5).

[0067] Next, in step S10, the control unit 11 determines whether or not it has received a response from tag Tg. For example, when tags 11 to 15 receive the transmission data, execute a command (lighting command), and send a response to controller C, controller C sends the received response to management server 1. As a result, the control unit 11 of management server 1 receives the response. When the control unit 11 receives the response (S10: Yes), the process proceeds to step S11.

[0068] In step S11, the control unit 11 determines whether the fourth time segment t4 has started. If the fourth time segment t4 has started (S11: Yes), in step S12, the control unit 11 outputs a transmission instruction for the transmission data to the controller D. When the controller D receives the transmission instruction, it sends the transmission data, which includes the tag Tg (e.g., tags 16-20) that will execute the command, to all tags Tg associated with the controller D (see Figure 5).

[0069] Next, in step S13, the control unit 11 determines whether or not it has received a response from tag Tg. For example, when tags 16 to 20 receive the transmission data, execute a command (lighting command), and send a response to controller D, controller D sends the received response to management server 1. As a result, the control unit 11 of management server 1 receives the response. When the control unit 11 receives the response (S13: Yes), the process moves to step S14.

[0070] In step S14, the control unit 11 determines whether the fifth time period t5 has started. If the fifth time period t5 has started (S14: Yes), in step S15, the control unit 11 outputs a transmission instruction for the transmission data to the controller E. When the controller E receives the transmission instruction, it sends the transmission data, which includes the tags Tg (e.g., tags 21-25) that will execute the command, to all tags Tg associated with the controller E (see Figure 5).

[0071] Next, in step S16, the control unit 11 determines whether or not it has received a response from tag Tg. For example, when tags 21 to 25 receive the transmission data and execute a command (lighting command), and send a response to controller E, controller E sends the received response to management server 1. As a result, the control unit 11 of management server 1 receives the response. If the control unit 11 receives the response (S16: Yes), the process returns to step S1.

[0072] Returning to step S1, the second cycle (N=2) begins. In step S2, the control unit 11 determines whether the first time segment t1 has started. If the first time segment t1 has started (S2: Yes), in step S3, the control unit 11 outputs a transmission instruction for the transmission data to controller A. Upon receiving the transmission instruction, controller A sends the transmission data, which includes the tag Tg (e.g., tags 1-5) that will execute the command, to all tags Tg associated with controller A (see Figure 5). The process thereafter is the same as described above. In this manner, the communication system 10 executes the communication process.

[0073] As described above, the communication system 10 according to this embodiment is a communication system in which a plurality of controllers 2 (master stations) and a plurality of tags Tg (slave stations) perform wireless communication at a predetermined period. The communication system 10 associates each of the plurality of tags Tg with one of the plurality of controllers 2. The communication system 10 also assigns each of the plurality of controllers 2 to each of a plurality of time divisions (time slots) obtained by dividing the predetermined period into time segments on a predetermined channel. The communication system 10 also causes the controller 2 and the plurality of tags Tg associated with the controller 2 to communicate within each of the plurality of time segments.

[0074] In the above configuration, each controller 2 uses radio waves only during the time segment (40 ms) within the period (e.g., 200 ms). Furthermore, by allocating (adjusting) the radio wave usage times of the controllers 2 so that they do not overlap, one channel (CH1) can be shared by up to 5 controllers 2. This makes it possible to install a large number of controllers 2 even when their communication areas AR overlap, as shown in Figure 11. For example, if there are 20 frequency channels, it is possible to install 100 controllers 2, which is five times the number of channels, even in areas where they radio-interfere with each other.

[0075] Furthermore, depending on the factory layout and the type of each line, it may be desirable to allocate channels while being mindful of the maximum number of channels that each controller 2 can share. In such cases, a display screen (UI) may be provided that allows the number of each controller (here, for example, "1" to "64") to be mapped to a table with axes representing time slots (slot numbers) and channels (frequency channels), as shown in Figure 12. In other words, the control unit 11 may visually display the predetermined channels and predetermined time divisions to which each of the multiple controllers 2 (master stations) has been assigned.

[0076] Furthermore, the transmitted data includes destination information for multiple tags Tg. With the above configuration, using a single channel, each controller 2 can communicate with multiple tags Tg in each time segment assigned to each controller 2 in each cycle. Therefore, a large number of tags Tg can be installed over a wide area. In addition, the amount of communication can be increased in the communication system 10. Thus, it is possible to install a large number of tags Tg while ensuring high-speed response of communication between the controller 2 and the tags Tg.

[0077] In the communication system 10 according to this embodiment, multiple controllers 2 (master stations) synchronize their time with each other and communicate within the time slots assigned by the allocation processing unit 112. Furthermore, the multiple controllers 2 may be connected to each other via wired communication.

[0078] Furthermore, when data to be transmitted is generated in the tag Tg (slave station), the communication processing unit 113 causes the controller 2 to which the tag Tg is associated to transmit the data within the time slot allocated to that controller 2.

[0079] Furthermore, the data to be transmitted by tag Tg is the data observed by that tag Tg. The data observed by tag Tg is data corresponding to the user interface operations performed on that tag Tg.

[0080] The present invention is not limited to the embodiments described above, and may also be provided in the following embodiments. For example, the communication system 10 may include multiple channels. In this case, the allocation processing unit 112 assigns each of the multiple controllers 2 to each of the multiple time divisions for each channel. As a result, for example, five controllers A to E share channel CH1, five controllers F to J share channel CH2, five controllers K to O share channel CH3, five controllers P to T share channel CH4, and five controllers U to Y share channel CH5. Each controller 2 communicates with multiple tags Tg in each of the multiple time divisions obtained by dividing a predetermined period into time divisions, as in the embodiments described above. With this configuration, the number of controllers 2 can be increased according to the number of available channels, making it possible to install more tags Tg.

[0081] Furthermore, the above embodiment shows an example where a 200ms period is divided into five 40ms slots, but this is just one example. The period, number of divisions, and slot time should be appropriately set considering the time response, power consumption, number of slave stations, number of available frequency channels, communication speed, etc., required for each application.

[0082] Furthermore, in the above-described embodiment, the management server 1 (arbitration station) controls the multiple controllers 2, but in another embodiment, a specific controller 2 among the multiple controllers 2 may also perform the functions of the management server 1. In this case, the specific controller 2 functions as the master controller, and the other controllers 2 function as slave controllers. The master controller performs an assignment process to assign each of the multiple slave controllers to each of a plurality of time divisions on a predetermined channel, and a communication process to cause the slave controllers to communicate with the plurality of tags Tg in each of the plurality of time divisions. The master controller transmits the transmission data to each slave controller in the order of the time divisions. Note that the controller 2 that functions as the master controller may be changed as appropriate depending on the communication status of the entire communication system 10.

[0083] As described above, the communication system of the present invention may consist of an entire communication system 10 (see Figure 1) including a management server 1, a controller 2, and a tag Tg, or it may consist of the management server 1 and the controller 2, or it may consist of the management server 1 alone or the controller 2 alone.

[0084] Furthermore, the communication system according to the present invention can also be constructed by freely combining the embodiments described above within the scope of the invention as described in each claim, or by appropriately modifying or omitting parts of each embodiment. [Explanation of Symbols]

[0085] 1: Management Server 2: Controller 10: Communication Systems 111: Related Processing Unit 112: Assignment Processing Unit 113: Communication Processing Unit C1 :Period Tg: Tag t1: 1st time segment t2: Second time interval t3: Third time interval t4: Fourth time interval t5: Fifth time interval

Claims

1. A communication system in which multiple master stations and multiple slave stations perform wireless communication at predetermined intervals, Each of the aforementioned child stations is associated with one of the aforementioned parent stations. An assignment processing unit that assigns each of the plurality of master stations to each of the plurality of time divisions obtained by dividing the predetermined period in a predetermined channel, A communication processing unit outputs a transmission instruction for transmission data, which includes command information for causing a first master station assigned to a first time segment among the multiple time segments to execute a predetermined process, and identification information for multiple first slave stations that execute the command information, with the identification information of the multiple first slave stations arranged in order, thereby causing the first master station to transmit the transmission data to multiple slave stations associated with the first master station within the first time segment. Equipped with, The first master station transmits the transmission data to the plurality of slave stations during the data transmission period of the first time division. Each of the plurality of first slave stations transmits an acknowledgment for the transmitted data to the first master station at different timings during the response reception period following the data transmission period. A communication system in which each of the plurality of first slave stations determines its own order in the transmission data from the order of the identification information of the plurality of first slave stations, and during the response reception period, transmits the acknowledgment to the first master station at the timing when the sum of the transmission time for the transmission of the acknowledgment by the first slave station that is in an order earlier than its own order and a predetermined margin time has elapsed from the end of the data transmission period.

2. The aforementioned multiple master stations synchronize their time with each other and communicate within the time slots assigned by the allocation processing unit. The communication system according to claim 1.

3. The aforementioned multiple base stations are connected to each other by wired communication. The communication system according to claim 1 or claim 2.

4. The communication processing unit causes the first master station to transmit the transmission data to a predetermined number of slave stations among the plurality of slave stations associated with the first master station. A communication system according to any one of claims 1 to 3.

5. The plurality of first slave stations transmit the acknowledgment to the first master station on a time-exclusive basis during the response reception period. A communication system according to any one of claims 1 to 4.

6. The first master station transmits the transmission data to a predetermined number of slave stations that can communicate with the first master station within the time interval. The communication system according to claim 4.

7. The communication processing unit outputs a transmission instruction for the transmission data to each of the multiple base stations in the order of the time divisions. A communication system according to any one of claims 1 to 6.

8. After the first master station transmits the transmission data to a predetermined number of slave stations among a plurality of slave stations associated with the first master station in the first time period, a second master station, different from the first master station, transmits the transmission data to a predetermined number of slave stations among a plurality of slave stations associated with the second master station in the second time period following the first time period. The communication system according to claim 4.

9. The first master station transmits the transmission data to a predetermined number of slave stations in a first time segment, and after the first master station receives the acknowledgment from the predetermined number of slave stations, the second master station transmits the transmission data to the predetermined number of slave stations. The communication system according to claim 8.

10. For the predetermined channel, a number of master stations capable of communicating with the plurality of slave stations at the predetermined interval is assigned. A communication system according to any one of claims 1 to 9.

11. The aforementioned communication system uses multiple channels, The allocation processing unit assigns each of the multiple master stations to each of the multiple time segments for each channel. A communication system according to any one of claims 1 to 10.

12. Each of the aforementioned multiple master stations is visually displayed in a way that allows for the identification of the predetermined channels and predetermined time segments to which each is assigned. A communication system according to any one of claims 1 to 11.

13. A communication method in which multiple base stations and multiple slave stations perform wireless communication at predetermined intervals, Each of the aforementioned child stations is associated with one of the aforementioned parent stations. One or more processors An assignment step of assigning each of the plurality of master stations to each of the plurality of time divisions obtained by dividing the predetermined period in a predetermined channel, A communication step in which the first master station, which is assigned to the first time segment of the aforementioned plurality of time segments, is given a transmission instruction for transmission data which includes command information to cause a predetermined process to be executed by the first master station, and identification information of a plurality of first slave stations that will execute the command information, and the identification information of the plurality of first slave stations is arranged in order, thereby causing the first master station to transmit the transmission data to a plurality of slave stations associated with the first master station within the first time segment. Execute, The first master station transmits the transmission data to the plurality of slave stations during the data transmission period of the first time division. Each of the plurality of first slave stations transmits an acknowledgment for the transmitted data to the first master station at different timings during the response reception period following the data transmission period. A communication method comprising: each of the plurality of first slave stations determines its own order in the transmission data from the order of the identification information of the plurality of first slave stations; and during the response reception period, at the timing when a time has elapsed from the end of the data transmission period that is the sum of the transmission time for the acknowledgment sent by the first slave station with an order earlier than its own and a predetermined margin time, it transmits the acknowledgment to the first master station.

14. A communication program in which multiple master stations and multiple slave stations perform wireless communication at predetermined intervals, Each of the aforementioned child stations is associated with one of the aforementioned parent stations. An assignment step of assigning each of the plurality of master stations to each of the plurality of time divisions obtained by dividing the predetermined period in a predetermined channel, A communication step in which the first master station, which is assigned to the first time segment of the aforementioned plurality of time segments, is given a transmission instruction for transmission data which includes command information to cause a predetermined process to be executed by the first master station, and identification information of a plurality of first slave stations that will execute the command information, and the identification information of the plurality of first slave stations is arranged in order, thereby causing the first master station to transmit the transmission data to a plurality of slave stations associated with the first master station within the first time segment. To have one or more processors execute this, The first master station transmits the transmission data to the plurality of slave stations during the data transmission period of the first time division. Each of the plurality of first slave stations transmits an acknowledgment for the transmitted data to the first master station at different timings during the response reception period following the data transmission period. A communication program in which each of the plurality of first slave stations determines its own order in the transmission data from the order of the identification information of the plurality of first slave stations, and during the response reception period, transmits the acknowledgment to the first master station at the timing when the sum of the transmission time for the transmission of the acknowledgment by the first slave station with an order earlier than its own and a predetermined margin time has elapsed from the end of the data transmission period.

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