RFID communication system, reader / writer, and RFID communication method

Abstract

To shorten a time required for communication between a reader / writer and an RF tag.SOLUTION: In an RFID communication system (100), a first reader / writer (10) comprises: an adjustment unit (13) which adjusts a communication parameter using for communication with an RF tag (30); and a first communication unit (12) which communicates with the RF tag (30), by using the communication parameter. A second reader / writer (20) comprises: an acquisition unit (23) which acquires the communication parameter when the RF tag (30) and the first reader / writer (10) perform communication success; and a second communication unit (22) which communicates with the RF tag (30), by using the acquired communication parameter.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an RFID communication system, a reader / writer, and an RFID communication method. [Background technology]

[0002] Information management systems using RFID (Radio Frequency Identification) technology are used in various fields. In RFID technology, communication parameters that enable communication with RF tags differ depending on the type of RF tag (e.g., RF tag model, etc.). Therefore, when a reader / writer performs initial communication (inventory) with an RF tag (also called an RFID tag), it adjusts the communication parameters to optimal parameters. By using communication parameters appropriate for the RF tag, the reader / writer can communicate with the RF tag.

[0003] For example, in Patent Document 1, optimal communication parameters that have previously resulted in successful communication between a reader / writer and an RF tag are stored in a storage device. A user operates the reader / writer to select an RF tag. The reader / writer communicates with the RF tag by using the optimal communication parameters for the RF tag stored in the storage device. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-122751 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, the amount of information managed by RFID has been increasing. As a result, it is expected that the time required for communication between a reader / writer and an RF tag will increase. For example, when multiple reader / writers are installed on a production line in a factory, each reader / writer adjusts communication parameters and communicates with the RF tags attached to the workpieces being transported. Therefore, the increase in the time required for communication raises concerns about a decrease in production efficiency. In order to improve production efficiency, it is necessary to shorten the time required for communication.

[0006] However, when using the configuration described in the cited document 1, the user must select the RF tag that will communicate with each reader / writer, making it difficult to use the configuration described in the cited document 1 on a production line where workpieces are transported continuously.

[0007] An object of one embodiment of the present invention is to reduce the time required for communication between a reader / writer and an RF tag. [Means for solving the problem]

[0008] In order to solve the above problems, an RFID communication system according to one example of the present disclosure is an RFID communication system including a first reader / writer and a second reader / writer, wherein the first reader / writer has an adjustment unit that adjusts communication parameters used for communication with an RF tag, and a first communication unit that communicates with the RF tag using the communication parameters, and the second reader / writer has an acquisition unit that acquires the communication parameters when communication between the RF tag and the first reader / writer is successful, and a second communication unit that communicates with the RF tag using the acquired communication parameters.

[0009] According to the above configuration, the time required for adjusting communication parameters in the second reader / writer, which is located downstream of the first reader / writer in the production line, can be reduced, thereby shortening the time required for communication between the reader / writer and the RF tag.

[0010] The acquisition unit may acquire a plurality of communication parameters when the first reader / writer successfully communicates with each of a plurality of RF tags, and information indicating the order in which the plurality of communication parameters were used in the first reader / writer, and the second communication unit may communicate with the plurality of RF tags by sequentially using the plurality of communication parameters in accordance with the order.

[0011] According to the above configuration, even when a larger number of works are transported between the first reader / writer and the second reader / writer, the communication parameters can be appropriately applied, thereby improving production efficiency.

[0012] The first reader / writer may further include a transmitter that transmits a tag ID indicating the RF tag and the communication parameters when communication between the RF tag and the first reader / writer is successful, in association with each other.

[0013] The first reader / writer may further include a transmitting unit that transmits a tag ID indicating the RF tag and the communication parameters used when the first reader / writer successfully communicated with the RF tag, in association with each other; the acquiring unit acquires the tag ID indicating the RF tag, a plurality of communication parameters used when the first reader / writer successfully communicated with each of a plurality of RF tags, and information indicating the order in which the plurality of communication parameters were used in the first reader / writer; and the second communication unit may determine the communication parameters to be used next based on the order and the tag ID of the RF tag with which the second communication unit communicated.

[0014] According to the above configuration, even if there is a discrepancy between the RF tags for which the first reader / writer and the second reader / writer use communication parameters, it is possible to appropriately determine the communication parameters to be used for the next RF tag to be transported, thereby preventing an increase in the time required for communication between the reader / writer and the RF tag.

[0015] The communication parameters may be parameters indicating modulation depth, modulation width, transmission power, reception gain, antenna channel, and / or polarization plane.

[0016] The system may further include a transport device for transporting the RF tag, and the RF tag may be transported by the transport device from a position where it can communicate with the first reader / writer to a position where it can communicate with the second reader / writer.

[0017] According to the above configuration, the second reader / writer can use communication parameters adjusted by the first reader / writer, thereby reducing the time required for communication between the reader / writer and the RF tag.

[0018] The communication device may further include a control device that controls the first reader / writer and the second reader / writer, and the acquisition unit may acquire the communication parameters from the first reader / writer via the control device.

[0019] A reader / writer according to one example of the present disclosure includes an acquisition unit that acquires communication parameters when an RF tag successfully communicates with another reader / writer, and a second communication unit that communicates with the RF tag using the acquired communication parameters.

[0020] A reader / writer according to one example of the present disclosure includes an adjustment unit that adjusts communication parameters used to communicate with an RF tag, a first communication unit that communicates with the RF tag using the communication parameters, and a transmission unit that transmits the communication parameters to another reader / writer when communication with the RF tag is successful.

[0021] An RFID communication method according to one example of the present disclosure includes a first communication process in which a first reader / writer communicates with an RF tag using communication parameters adjusted for communicating with the RF tag, an acquisition process in which a second reader / writer acquires the communication parameters when communication is successful in the first communication process, and a second communication process in which the second reader / writer communicates with the RF tag using the communication parameters acquired in the acquisition process. [Effects of the Invention]

[0022] According to one aspect of the present invention, it is possible to reduce the time required for communication between a reader / writer and an RF tag. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing an RFID communication system according to a first embodiment of the present invention. [Figure 2] 2 is a functional block diagram showing an example of a configuration of a main part of the RFID communication system shown in FIG. 1. FIG. [Figure 3] 2 is a diagram showing a sequence of communication between the first reader / writer shown in FIG. 1 and an RF tag. FIG. [Figure 4] 2 is a flowchart illustrating a method of communication between the first reader / writer shown in FIG. 1 and an RF tag. [Figure 5] 10 is a flowchart illustrating a method of communication between the second reader / writer shown in FIG. 1 and an RF tag. [Figure 6] 10 is a flowchart illustrating a method of communication between a first reader / writer and an RF tag according to a modified example of the first embodiment. [Figure 7] 10 is a flowchart illustrating a method of communication between a second reader / writer and an RF tag according to a modified example of the first embodiment. [Figure 8] FIG. 10 is a functional block diagram showing an example of a configuration of a main part of an RFID communication system according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0024] Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described with reference to the drawings.

[0025] (Embodiment 1) §1 Application Examples An example of a situation in which the present invention is applied will be described with reference to Fig. 1. Fig. 1 is a schematic diagram showing an RFID communication system 100 according to the present embodiment 1. The RFID communication system 100 is used to manage information on RF tags attached to workpieces W transported by a transport device, for example, on a production line in a factory or the like.

[0026] 1, the RFID communication system 100 includes a first reader / writer 10 and a plurality of second reader / writers 20. Although three second reader / writers 20 are provided in FIG. 1, the number is not limited to this. It is sufficient that at least one second reader / writer 20 is provided.

[0027] In the RFID communication system 100, a plurality of workpieces W are transported by a transport device (not shown). The workpieces W move on a transport path (not shown). In FIG. 1, the transport direction L of the workpieces W transported by the transport device is indicated by an arrow. An RF tag is attached to the transported workpieces W. Information about the workpieces W is managed by the RF tag. The plurality of RF tags may be of multiple types. Different types of RF tags may require different appropriate communication parameters. Furthermore, even if the type of RF tag is the same, the appropriate communication parameters may differ due to individual differences between RF tags, etc.

[0028] The first reader / writer 10 and the multiple second reader / writers 20 each have an antenna 11, 21. The antennas 11, 21 transmit and receive information (communicate) with the RF tag using electromagnetic waves or AC magnetic fields. The first reader / writer 10 and the multiple second reader / writers 20 communicate with the RF tag attached to the workpiece W via the antennas 11, 21, and read and write information from and to the RF tag.

[0029] The antennas 11, 21 of the first reader / writer 10 and the multiple second reader / writers 20 are provided adjacent to the transport path of the transported work W. The antenna 11 of the first reader / writer 10 is provided at the most upstream position in the transport direction L. In other words, the antennas 21 of the multiple second reader / writers 20 are provided downstream of the first reader / writer 10 in the transport direction L.

[0030] The first reader / writer 10 can communicate with each of the multiple second reader / writers 20. When the first reader / writer 10 has successfully communicated with the RF tag of the transported workpiece W, it transmits communication parameters to each of the second reader / writers 20. In Fig. 1, the transmission direction P of the communication parameters when communication has been successful is indicated by an arrow.

[0031] The workpiece W transported in the transport direction L by the transport device is transported to a position where it can communicate with the first reader / writer 10. The first reader / writer 10 communicates with the RF tag of the workpiece W transported to the communication position. Thereafter, the workpiece W is transported from the position where it can communicate with the first reader / writer 10 to a position where it can communicate with each of the multiple second reader / writers 20. Each second reader / writer 20 communicates with the RF tag 30 of the workpiece W transported to the communication position.

[0032] According to the above configuration, the second reader / writers 20 can use communication parameters adjusted by the first reader / writer 10. Therefore, the second reader / writers 20 do not need to adjust communication parameters used for communication with RF tags. This reduces the time required for communication between the reader / writers and the RF tags.

[0033] §2 Configuration example The configuration of the RFID communication system 100 according to the first embodiment will be described in detail below with reference to Fig. 2. Fig. 2 is a functional block diagram showing an example of the configuration of the main parts of the RFID communication system 100 shown in Fig. 1.

[0034] [Configuration of the first reader / writer] The first reader / writer 10 communicates with the RF tag 30 using the communication parameters. After communicating with the RF tag 30, the first reader / writer 10 reads and / or writes information from and to the RF tag 30. In the example of FIG. 2 , the first reader / writer 10 includes a first communication unit 12, an adjustment unit 13, and a transmission unit 14.

[0035] The first communication unit 12 communicates with the RF tag 30 using communication parameters. The communication parameters may be, for example, parameters indicating the modulation depth or modulation width of the signal used in communication, transmission power, reception gain, antenna channel, and / or polarization plane (in the case of UHF), but are not limited to these. The communication parameters may include various parameters that can be adjusted on the first reader / writer 10 side to communicate with the RF tag 30. The first communication unit 12 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30. The first communication unit 12 attempts to communicate with the RF tag 30 using the communication parameters adjusted by the adjustment unit 13, which will be described later. If communication with the RF tag 30 is successful, the first communication unit 12 reads and / or writes information from and to the RF tag 30.

[0036] The first communication unit 12 stores information read from the RF tag 30 in a storage unit (not shown) of the first reader / writer 10. The first communication unit 12 also reads information to be written to the RF tag 30 from the storage unit of the first reader / writer 10. The first communication unit 12 also stores information related to communication with the RF tag 30 in the storage unit of the first reader / writer 10. For example, the first communication unit 12 stores tag IDs (identifiers) indicating one or more RF tags 30 with which communication has been successful, and communication parameters used to successfully communicate with each of the one or more RF tags 30, in the storage unit of the first reader / writer 10. For example, the first communication unit 12 may also store information indicating the order in which communication parameters were used when communication with each of the multiple RF tags 30 was successful (the order of multiple communication parameters corresponding to the multiple RF tags that communicated), in the storage unit of the first reader / writer 10.

[0037] The adjustment unit 13 adjusts the communication parameters used by the first communication unit 12 to communicate with the RF tag 30. The adjustment unit 13 sets the communication parameters used by the first communication unit 12 when performing an inventory (communication by an inventory command) to specific first communication parameters. If the RF tag 30 and the first communication unit 12 cannot communicate with each other using the set first communication parameters, the adjustment unit 13 changes the communication parameters. The adjustment unit 13 changes, for example, the modulation degree or modulation width of the signal used for communication, the transmission power, the reception gain, the antenna channel, and / or the polarization plane. The communication parameters to be adjusted may include one or more parameters. The adjustment unit 13 may change one or more of the communication parameters.

[0038] The transmitter 14 transmits information relating to communication between the first reader / writer 10 and the RF tag 30 to the second reader / writer 20. The transmitter 14 transmits to the second reader / writer 20 communication parameters used when the first communicator 12 successfully communicated with each of the multiple RF tags 30, and information indicating the order in which the communication parameters were used when communication was successful with each of the multiple RF tags 30. The transmitter 14 may also transmit to the second reader / writer 20 the tag ID of the RF tag 30 with which communication was successful and the communication parameters used when communication was successful with that RF tag 30, in association with each other.

[0039] [Configuration of the second reader / writer] The second reader / writer 20 communicates with the RF tag 30 using the communication parameters used when the first reader / writer 10 successfully communicated. The second reader / writer 20 communicates with the RF tag 30 with which the first reader / writer 10 communicated. After communicating with the RF tag 30, the second reader / writer 20 reads and / or writes information from and to the RF tag 30. In the example of FIG. 2, the second reader / writer 20 includes a second communication unit 22 and an acquisition unit 23.

[0040] The acquiring unit 23 acquires information relating to communication with the RF tag 30 transmitted from the transmitting unit 14 of the first reader / writer 10. The acquiring unit 23 acquires communication parameters transmitted from the transmitting unit 14 when the first reader / writer 10 successfully communicated with each of the multiple RF tags 30, and information indicating the order in which the communication parameters were used when the first reader / writer 10 successfully communicated with each of the multiple RF tags 30. The acquiring unit 23 receives, for example, from the first reader / writer 10, a list in which communication parameters are arranged corresponding to the order in which the first reader / writer 10 communicated with the RF tags 30. Alternatively, the acquiring unit 23 stores the transmission order of the communication parameters transmitted from the first reader / writer 10 in the storage unit of the second reader / writer 20. The order of the communication parameters in the list or the transmission order of the communication parameters indicates the order in which the communication parameters were used. Alternatively, the acquiring unit 23 receives, for example, from the first reader / writer 10, a list including communication parameters used when the first reader / writer 10 successfully communicated with each of the multiple RF tags 30. The list may include a number indicating the order of communication (the order in which the communication parameters were used) corresponding to each communication parameter. In this way, the acquiring unit 23 acquires information indicating the order in which the communication parameters were used.

[0041] The second communication unit 22 communicates with the RF tag 30 using the communication parameters. The second communication unit 22 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30. When performing inventory, the second communication unit 22 communicates with the RF tag 30 using the communication parameters acquired by the acquisition unit 23.

[0042] The second communication unit 22 communicates with the multiple RF tags 30 by sequentially using the acquired communication parameters according to the information indicating the order of acquisition by the acquisition unit 23. That is, the second communication unit 22 sequentially uses the acquired communication parameters in the same order as the order in which the first reader / writer 10 used the communication parameters in successful communication. Therefore, the second communication unit 22 can perform inventory communication for a transported RF tag 30 by using, from the beginning, the communication parameters used when the RF tag 30 and the first reader / writer 10 successfully communicated with each other.

[0043] According to the above configuration, the second reader / writer 20 can appropriately apply the communication parameters in accordance with the order in which the first reader / writer 10 used the communication parameters, even when a larger number of workpieces W are transported between the first reader / writer 10 and the second reader / writer 20. This can improve production efficiency.

[0044] When communication with the RF tag 30 is successful, the second communication unit 22 reads information from and / or writes information to the RF tag 30. The second communication unit 22 stores the information read from the RF tag 30 in a memory unit of the second reader / writer 20 (not shown). The second communication unit 22 also reads information to be written to the RF tag 30 from the memory unit of the second reader / writer 20.

[0045] It is assumed that the first communication unit 12 and the second communication unit 22 have similar communication performance (for example, they communicate using the same type of antenna). Therefore, the communication parameters adjusted in the first reader / writer 10 can also be suitably used in the second reader / writer 20.

[0046] [RF tag configuration] The RF tag 30 is attached to a workpiece W and stores information about the attached workpiece W. In the example of FIG. 2, the RF tag 30 includes a tag communication unit 31. The tag communication unit 31 communicates with the first communication unit 12 of the first reader / writer 10 and the second communication unit 22 of the second reader / writer 20.

[0047] The tag communication unit 31 transmits and receives information to and from the first reader / writer 10 and the second reader / writer 20. When communication with the first reader / writer 10 or the second reader / writer 20 is successful, the tag communication unit 31 transmits a response indicating successful communication to the first communication unit 12 or the second communication unit 22. The tag communication unit 31 transmits a tag ID indicating the RF tag 30 together with the response to the first communication unit 12 or the second communication unit 22. When communication is successful, the tag communication unit 31 receives information from and / or transmits information to the first communication unit 12 or the second communication unit 22.

[0048] The information read by the first reader / writer 10 or the second reader / writer 20 is stored in a memory unit (not shown) of the RF tag 30. In addition, the information received from the first reader / writer 10 or the second reader / writer 20 is written in the memory unit of the RF tag 30.

[0049] According to the above-described configuration of the first reader / writer 10 and the second reader / writer 20, it is possible to reduce the time required to adjust communication parameters in the second reader / writer 20, which is placed downstream in the production line from the first reader / writer 10. This reduces the time required for communication between the reader / writer and the RF tag.

[0050] (Embodiment 2) Another embodiment of the present invention will be described below with reference to Fig. 8. For ease of explanation, members having the same functions as those described in the above embodiment will be denoted by the same reference numerals, and their description will not be repeated.

[0051] 8 is a functional block diagram showing an example of a configuration of a main part of an RFID communication system 100A according to Embodiment 2 of the present invention. In the example of FIG. 8, the RFID communication system 100A includes a first reader / writer 10A, a second reader / writer 20A, and a control device 40.

[0052] In the example of FIG. 8, the first reader / writer 10A includes a first communication unit 12, an adjustment unit 13, and a first communication unit (transmission unit) 15.

[0053] The first communication unit 15 communicates information with the control device 40. The first communication unit 15 transmits information relating to communication between the first reader / writer 10A and the RF tag 30 to the control device 40. The first communication unit 15 is connected to the control device 40 so as to enable transmission and reception of information therebetween. The first communication unit 15 transmits to the control device 40, for example, communication parameters used to successfully communicate with the RF tag 30 and information indicating the order in which the communication parameters were used when communication with multiple RF tags 30 was successful.

[0054] In the example of FIG. 8, the second reader / writer 20A includes a second communication unit 22 and a second communication unit (acquisition unit) 24.

[0055] The second communication unit 24 communicates information with the control device 40. The second communication unit 24 is connected to the control device 40 so as to be able to send and receive information to and from the control device 40. The second communication unit 24 acquires information relating to communication between the first reader / writer 10A and the RF tag 30. The second communication unit 24 acquires, from the control device 40, for example, communication parameters used when the RF tag 30 and the first reader / writer 10A successfully communicated, and information indicating the order in which the communication parameters were used when the first reader / writer 10A successfully communicated with multiple RF tags 30.

[0056] The control device 40 is a device that controls the first reader / writer 10 A and the second reader / writer 20 A. The control device 40 includes a third communication unit 41.

[0057] The third communication unit 41 is connected to the first communication unit 15 of the first reader / writer 10A and the second communication unit 24 of the second reader / writer 20A so as to enable transmission and reception of information. The third communication unit 41 communicates information with the first communication unit 15 and the second communication unit 24.

[0058] The third communication unit 41 transmits information received from the first communication unit 15 of the first reader / writer 10A to the second communication unit 24 of the second reader / writer 20A. That is, the information from the first reader / writer 10A is transmitted to the second reader / writer 20A via the control device 40. For example, the communication parameters transmitted by the first communication unit 15 with which the first reader / writer 10A successfully communicated with the RF tag 30 and the information indicating the order in which the communication parameters were used when the first reader / writer 10A successfully communicated with multiple RF tags 30 are transmitted to the second communication unit 24 via the third communication unit 41.

[0059] §3 Example of operation An example of processing by the RFID communication system 100 will be described below.

[0060] [Sequence of communication between the first reader / writer and RF tag] The sequence during communication between the first reader / writer 10 and the RF tag 30 will be described using Fig. 3. Fig. 3 is a diagram showing the sequence during communication between the first reader / writer 10 and the RF tag 30. Reference numeral 1000 in Fig. 3 indicates the sequence when communication between the RF tag 30 and the first reader / writer 10 is successful. Reference numeral 1001 in Fig. 3 indicates the sequence when the first reader / writer 10 is attempting to communicate with the RF tag 30.

[0061] A sequence will be described when communication between the RF tag 30 and the first reader / writer 10 is successful. As indicated by reference numeral 1000 in Fig. 3, the first reader / writer 10 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30 (S1). From step S1, the first reader / writer 10 attempts to communicate with the RF tag 30. If communication between the first reader / writer 10 and the RF tag 30 is successful, the RF tag 30 transmits a response indicating successful communication to the first reader / writer 10 (S2). In step S2, the RF tag 30 transmits a tag ID indicating the RF tag 30 to the first reader / writer 10 together with the response indicating successful communication.

[0062] If the first reader / writer 10 succeeds in communicating with the RF tag 30, it transmits to the RF tag 30 a command to read information from the RF tag 30 or a command to write information to the RF tag 30 (S3). In step S3, the first reader / writer 10 communicates with the RF tag 30 by specifying the tag ID transmitted in step S2.

[0063] When the first reader / writer 10 finishes reading information from the RF tag 30 or writing information to the RF tag 30 in step S3, the RF tag 30 transmits a processing completion response to the first reader / writer 10 (S4).

[0064] Steps S3 and S4 are repeated until all information processing (reading and / or writing of information) between the first reader / writer 10 and the RF tag 30 is completed. Note that the sequence when the second reader / writer 20 has successfully communicated is the same as the sequence described above.

[0065] Next, a description will be given of a sequence when the first reader / writer 10 attempts to communicate with the RF tag 30. As indicated by reference numeral 1001 in Fig. 3, the first reader / writer 10 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30 (S1).

[0066] If the first reader / writer 10 does not receive a response from the RF tag 30 or receives an abnormal response from the RF tag 30, it changes the communication parameters used to communicate with the RF tag 30 and transmits a command to the RF tag 30 to perform an inventory (S1). The first reader / writer 10 repeats step 1 until it is successful in communicating with the RF tag 30. That is, the first reader / writer 10 changes the communication parameters in various ways until it is successful in communicating with the RF tag 30, and repeats the process of sending an inventory command using the changed communication parameters. Note that in a sequence in which the second reader / writer 20 is attempting to communicate with the RF tag 30, it repeats step S1 using the acquired communication parameters (until the RF tag 30 is transported to a position where communication is possible).

[0067] [Method of communication between the first reader / writer and RF tags] A method of communication between the first reader / writer 10 and the RF tag 30 will be described with reference to Fig. 4. Fig. 4 is a flowchart illustrating a method of communication between the first reader / writer 10 and the RF tag 30. Note that the processing procedure described below is merely an example, and each process may be changed to the extent possible. Furthermore, steps in the processing procedure described below may be omitted, replaced, or added as appropriate depending on the embodiment.

[0068] First, the first reader / writer 10 sets specific first communication parameters to be used for initial communication with the RF tag 30 (S10). Next, the first reader / writer 10 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30 using the communication parameters set in step S1 (S11).

[0069] Next, the first reader / writer 10 determines whether communication with the RF tag 30 has been successful (S12). If communication with the RF tag 30 has not been successful (S12: NO), the first reader / writer 10 changes the communication parameters used for communication with the RF tag 30 (S13). In step S13, the first reader / writer 10 sets unused communication parameters that have not been used for communication with the RF tag 30. After step S13, the process returns to step S12.

[0070] If communication with the RF tag 30 is successful (S12: YES), the first reader / writer 10 performs a process of reading information from the RF tag 30 and / or writing information to the RF tag 30 (S14). Note that the first communication process in this disclosure corresponds to the process flow from step S11 to step S14.

[0071] After step S14, the first reader / writer 10 transmits to the second reader / writer 20 (S15) the communication parameters used when communication with the RF tag 30 was successful and information indicating the order in which communication with each of the multiple RF tags 30 was successful. After step S15, the first reader / writer 10 ends communication with the RF tag 30.

[0072] [About communication between the second reader / writer and RF tags] A method of communication between the second reader / writer 20 and the RF tag 30 will be described with reference to Fig. 5. Fig. 5 is a flowchart illustrating a method of communication between the second reader / writer 20 and the RF tag 30. Note that the processing procedure described below is merely an example, and each process may be changed to the extent possible. Furthermore, steps in the processing procedure described below may be omitted, replaced, or added as appropriate depending on the embodiment.

[0073] First, the second reader / writer 20 acquires the communication parameters when the RF tag 30 and the first reader / writer 10 successfully communicated with each other, and information indicating the order in which the communication parameters were used when the first reader / writer 10 successfully communicated with each of the multiple RF tags 30 (S20). Next, the second reader / writer 20 sets the communication parameters to be used for communication with the RF tag 30 to the communication parameters acquired in S20 (S21). In step S21, the second reader / writer 20 sequentially sets the communication parameters to be used for communication with the RF tag 30 according to the information indicating the order acquired in step S20.

[0074] Next, the second reader / writer 20 transmits a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30 using the communication parameters set in step S21 (S22). After step S22, the second reader / writer 20 determines whether communication with the RF tag 30 has been successful (S23).

[0075] If communication with the RF tag 30 is not successful (S23: NO), the process returns to step S22. If communication with the RF tag 30 is successful (S23: YFS), the second reader / writer 20 performs processing to read information from the RF tag 30 and / or write information to the RF tag 30 (S24). Note that the second communication processing in this disclosure corresponds to the processing flow from step S22 to step S24. After step S24, the second reader / writer 20 ends communication with the RF tag 30.

[0076] §4 Variations A modification of the first embodiment (hereinafter also referred to as "this modification") will be described with reference to Figures 6 and 7. For ease of explanation, members having the same functions as those described in the above embodiment will be denoted by the same reference numerals, and their description will not be repeated.

[0077] In this modified example, the transmitter 14 of the first reader / writer 10 transmits to the second reader / writer 20 a tag ID indicating the RF tag 30 with which communication has been successful, in association with the communication parameters used when communication with the RF tag 30 was successful.

[0078] In this modification, the acquisition unit 23 of the second reader / writer 20 further acquires a tag ID indicating the RF tag 30 from the transmission unit 14 of the first reader / writer 10. The second communication unit 22 of the second reader / writer 20 determines the next communication parameters to be used based on the information acquired by the acquisition unit 23 indicating the order in which the first reader / writer 10 used communication parameters and the tag ID of the RF tag 30 with which the second communication unit 22 communicated.

[0079] [Method of communication between the first reader / writer and RF tags] A method of communication between the first reader / writer 10 and the RF tag 30 in this modified example will be described with reference to Fig. 6. Fig. 6 is a flowchart illustrating a method of communication between the first reader / writer 10 and the RF tag 30 in this modified example. Note that steps S30 to S33 and S35 shown in Fig. 6 correspond to steps S10 to S14 shown in Fig. 4, and therefore description thereof will be omitted.

[0080] After the first reader / writer 10 has successfully communicated with the RF tag 30 (S32: YES), it acquires the tag ID of the RF tag 30 from the RF tag 30 (S34). After step S35, the first reader / writer 10 transmits to the second reader / writer 20 the tag ID of the RF tag 30 with which communication has been successful, the communication parameters used when communication was successful, and information indicating the order in which the communication parameters were used (S36). In step S35, the first reader / writer 10 associates the tag ID of the RF tag 30 with which communication has been successful and the communication parameters used when communication with the RF tag 30 was successful.

[0081] [About communication between the second reader / writer and RF tags] A method of communication between the second reader / writer 20 and the RF tag 30 will be described with reference to Fig. 7. Fig. 7 is a flowchart illustrating a method of communication between the second reader / writer 20 and the RF tag 30 according to this modified example. Steps S42 to S44 shown in Fig. 7 correspond to steps S22 to S24 shown in Fig. 5, and therefore description thereof will be omitted.

[0082] First, the second reader / writer 20 acquires the tag ID of the RF tag 30 with which the first reader / writer 10 has successfully communicated, the communication parameters used when the RF tag 30 and the first reader / writer 10 have successfully communicated, and information indicating the order in which the communication parameters were used when the first reader / writer 10 has successfully communicated with multiple RF tags 30 (S40).

[0083] Next, the second reader / writer 20 sets the communication parameters to be used for communication with the RF tag 30 to the communication parameters with which the first reader / writer 10 successfully communicated with the RF tag 30 that is transported next after the RF tag 30 with which the second reader / writer 20 communicated (S41). In step S41, the second reader / writer 20 determines the communication parameters to be used next based on the information indicating the order acquired in step S40 and the tag ID of the RF tag 30 with which the second reader / writer 20 communicated. Note that if the second reader / writer 20 is not communicating with an RF tag 30 (when communicating with the RF tag 30 that is transported first), the second reader / writer sets the communication parameters to the communication parameters that the first reader / writer 10 used first based on the information indicating the order acquired in step S40.

[0084] In step S42, the second reader / writer 20 uses the communication parameters set in step S41 to transmit a command to the RF tag 30 to perform initial communication (inventory) with the RF tag 30 (S42).

[0085] For example, it is conceivable that the workpiece W being transported may be lost (removed) during transport for some reason, or that the workpiece W may be transported without communication between the RF tag 30 and the second reader / writer 20A. However, with the above configuration, even if there is a discrepancy between the RF tag 30 for which communication parameters are used between the first reader / writer 10A and the second reader / writer 20A, it is possible to appropriately determine the communication parameters to be used for the next RF tag 30 to be transported. This makes it possible to prevent an increase in the time required for communication between the reader / writer and the RF tag.

[0086] [Software implementation example] The functions of the first reader / writer 10, 10A and the second reader / writer 20, 20A (hereinafter referred to as "devices") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each functional block of the device (particularly each part included in the first reader / writer 10, 10A and the second reader / writer 20, 20A).

[0087] In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The control device and storage device execute the program, thereby realizing the functions described in each of the above embodiments.

[0088] The program may be non-transitory and may be recorded on one or more computer-readable recording media. The recording media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

[0089] Furthermore, some or all of the functions of the control blocks can be realized by logic circuits. For example, an integrated circuit in which a logic circuit that functions as each of the control blocks is formed is also included in the scope of the present invention. In addition, the functions of the control blocks can also be realized by, for example, a quantum computer.

[0090] The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention. [Explanation of symbols]

[0091] 10, 10A First reader / writer 12 First Communication Section 13 Adjustment part 14 Transmitter 20, 20A Secondary Reader / Writer 22 Second Communication Section 23 Acquisition Department 30 RF tags 31 Tag communication unit 40 Control device 100, 100A RFID communication system

Claims

1. An RFID communication system including a first reader / writer and a second reader / writer, The first reader / writer an adjustment unit that adjusts communication parameters used in communication with the RF tag; a first communication unit that communicates with the RF tag using the communication parameters; The second reader / writer an acquisition unit that acquires the communication parameters when communication between the RF tag and the first reader / writer is successful; a second communication unit that communicates with the RF tag using the acquired communication parameters; the acquiring unit acquires a plurality of communication parameters when communication between each of a plurality of RF tags and the first reader / writer is successful, and information indicating an order in which the plurality of communication parameters are used in the first reader / writer; The second communication unit communicates with the plurality of RF tags using the plurality of communication parameters in sequence according to the order.

2. An RFID communication system including a first reader / writer and a second reader / writer, The first reader / writer an adjustment unit that adjusts communication parameters used in communication with the RF tag; a first communication unit that communicates with the RF tag using the communication parameters; a transmitter that transmits a tag ID indicating the RF tag and the communication parameters when communication between the RF tag and the first reader / writer is successful, in association with each other; Equipped with The second reader / writer an acquisition unit that acquires the communication parameters when communication between the RF tag and the first reader / writer is successful; and a second communication unit that communicates with the RF tag using the acquired communication parameters.

3. An RFID communication system including a first reader / writer and a second reader / writer, The first reader / writer an adjustment unit that adjusts communication parameters used in communication with the RF tag; a first communication unit that communicates with the RF tag using the communication parameters; a transmitter that transmits a tag ID indicating the RF tag and the communication parameters when communication between the RF tag and the first reader / writer is successful, in association with each other; Equipped with The second reader / writer an acquisition unit that acquires the communication parameters when communication between the RF tag and the first reader / writer is successful; a second communication unit that communicates with the RF tag using the acquired communication parameters; the acquiring unit acquires a tag ID indicating the RF tag, a plurality of communication parameters when communication between each of the plurality of RF tags and the first reader / writer is successful, and information indicating the order in which the plurality of communication parameters are used in the first reader / writer; The second communication unit determines the communication parameters to be used next based on the order and the tag ID of the RF tag with which the second communication unit has communicated.

4. An RFID communication system including a first reader / writer and a second reader / writer, The first reader / writer an adjustment unit that adjusts communication parameters used in communication with the RF tag; a first communication unit that communicates with the RF tag using the communication parameters; The second reader / writer an acquisition unit that acquires the communication parameters when communication between the RF tag and the first reader / writer is successful; a second communication unit that communicates with the RF tag using the acquired communication parameters; the RFID communication system further includes a control device that controls the first reader / writer and the second reader / writer, The acquisition unit acquires the communication parameters from the first reader / writer via the control device.

5. The RF tag transport device further includes:

5. The RFID communication system according to claim 1, wherein the RF tag is transported by the transport device from a position where communication with the first reader / writer is possible to a position where communication with the second reader / writer is possible.

6. an acquisition unit that acquires communication parameters when communication between the RF tag and another reader / writer is successful; a second communication unit that communicates with the RF tag using the acquired communication parameters; the acquiring unit acquires a plurality of communication parameters when communication between each of a plurality of RF tags and the other reader / writer is successful, and information indicating the order in which the plurality of communication parameters are used in the other reader / writer; The second communication unit communicates with the plurality of RF tags by sequentially using the plurality of communication parameters in accordance with the order.

7. an adjustment unit that adjusts communication parameters used in communication with the RF tag; a first communication unit that communicates with the RF tag using the communication parameters; a transmitter that transmits the communication parameters to another reader / writer when communication with the RF tag is successful; The transmitter transmits to the other reader / writer a plurality of communication parameters when communication with each of a plurality of RF tags is successful, and information indicating the order in which the plurality of communication parameters were used.

8. a first communication process in which a first reader / writer communicates with an RF tag using communication parameters adjusted for communicating with the RF tag; an acquisition process in which the second reader / writer acquires the communication parameters when communication is successful in the first communication process; a second communication process in which the second reader / writer communicates with the RF tag using the communication parameters acquired in the acquisition process, In the acquisition process, a plurality of communication parameters are acquired when the first reader / writer has successfully communicated with each of a plurality of RF tags, and information indicating the order in which the first reader / writer used the plurality of communication parameters is acquired; In the second communication process, the plurality of communication parameters are used in sequence in accordance with the order to communicate with the plurality of RF tags.

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