JP5216731B2 - Wireless tag reader, wireless tag reading program - Google Patents

Description

  The present invention relates to a wireless tag reading device for reading information of a wireless tag attached to an article, and a wireless tag reading program executed in the device.

  There is an RFID (Radio Frequency Identification) system that reads information on a wireless tag attached to an article, for example, a product without contact, and sends the read information to a host device, such as a server. Since the RFID tag reader in the RFID system has a feature such as being able to read information of a plurality of RFID tags at once, application to distribution management and production management of products is rapidly spreading.

  Regarding the wireless tag, a global standard is required in consideration of the internationalization of physical distribution. EPCglobal is one of those standards. In this EPCglobal, not only the physical standard of the wireless tag such as frequency band and radio wave output, but also an ID (EPC: Electronic Product Code) written on the wireless tag and information (ID information) associated with the ID A standard for how to distribute the network in the network is also established.

  For example, in an RFID system, information read from a wireless tag by a plurality of RFID readers is temporarily stored in a buffer of a wireless tag reader (RFID reader control PC), and a reading interval specified in a reading setting received from a client PC To send the temporarily stored information to the upper server.

Conventionally, various methods have been considered as a method for smoothly transmitting information in a system.
For example, Patent Document 1 describes a router that avoids network congestion in a client / server model. In Patent Document 1, when congestion occurs on a router that spans between a client and a server, the access from the client to the server is restricted from those having a large load. When the load is concentrated on a specific port or service, it is possible to set to restrict access to the port or service.

  Patent Document 2 describes a traffic reduction method in an RFID system. In Patent Document 2, the downstream server stores the product information of the wireless tag output from the reader / writer in a database and executes various processes. When the product information necessary for various processes is not stored in the database, a product information transmission request is output to the upstream server. The upstream server transmits the product information to the downstream server in response to the transmission request and stores the history of the transmission request in the history database to determine the priority for the product information. The upstream server outputs a predetermined number of product information with high priority to the reader / writer as information to be written in the wireless tag.

  In the conventional RFID system, when the reading is executed according to the reading setting from the client PC, the reading result according to the reading setting cannot always be transmitted to the server. For example, in a series of flows, if the frequency and amount of information stored in the RFID tag reader is large, the buffer overflows, and the reading result requested by the server may not be transmitted. is there.

  Concentration of data can be avoided by restricting access as in the invention described in Patent Document 1, but for example, in an RFID system, if read restriction is given to some of a plurality of RFID readers , Information from some wireless tags cannot be obtained at all.

  In the invention described in Patent Document 2, the information read from the wireless tag is stored in the database of the server, and no consideration is given to the buffer overflow of the information read from the wireless tag.

  The present invention has been made based on such circumstances, and the purpose of the present invention is to provide a wireless device capable of transmitting necessary information even in a situation where the wireless tag that is originally expected cannot be read. It is an object of the present invention to provide a tag reading device and a wireless tag reading program that allows a computer to function as a wireless tag reading device.

  The present invention relates to a wireless tag reader that reads information of a wireless tag attached to an article, read setting management means for managing a plurality of read settings indicating the content of reading the information, and information read from the wireless tag. A storage means for storing, a monitoring means for monitoring the free capacity of the storage means, and a reading setting for reading information from the wireless tag based on the free capacity of the storage means monitored by the monitoring means And a control means for reading information from the wireless tag in accordance with the reading setting and storing the information in the storage means.

  According to the present invention in which such a measure is taken, there is an effect that necessary information can be transmitted even in a situation where the wireless tag that is originally expected cannot be read.

The block diagram which shows the structure of the RFID system in this embodiment. The flowchart which shows operation | movement of RFID reader control PC14 in this embodiment. The figure which shows an example of the reading setting data containing the three reading settings to which priority 1, 2, and 3 were attached | subjected in this embodiment. The flowchart shown about the reading setting change process performed in RFID reader control PC14 in this embodiment. The flowchart shown about the modification of the reading setting change process performed in RFID reader control PC14 in this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an RFID system in the present embodiment. As shown in FIG. 1, the RFID system includes a client PC (personal computer) 10 (10-1, 10-2,...), A server 12, an RFID reader control PC (personal computer) 14, and an RFID reader 16 (16-1). , 16-2, 16-3, ...) are included. The RFID system according to the present embodiment is configured according to EPCglobal, for example, and can read information on the wireless tag 18 (RFID tag) attached to an article or the like and store it in the database 12a of the server 12.

  The client PC 10 is operated by a user of the system, and reads how the RFID tag 16 is read by the RFID readers 16-1, 16-2, 16-3,. Send reading settings to instruct the method. The client PC 10 executes a process for creating a reading setting and transmitting it to the RFID reader control PC 14 by executing the application (program) 10a by the processor. According to the application 10a, a plurality of reading settings with priorities can be transmitted to one RFID reader control PC 14, and information can be read from the wireless tag 18. The reading setting includes, for example, information indicating the RFID reader 16 used for reading, a reading time interval indicating an interval at which a reading result is transmitted from the RFID reader control PC 14 to the server 12, and filtering information indicating what information is necessary / unnecessary. Etc. are included. The filtering information includes information indicating the data format to be transmitted to the server 12. For example, priorities are given in the order of decreasing the amount of information transmitted to the server 12.

  The RFID reader control PC 14 reads the tag ID 18 a from the wireless tag 18 according to the reading setting received from the client PC 10, and transmits the reading result to the server 12. The RFID reader control PC 14 can receive reading settings from the plurality of client PCs 10-1, 10-2,..., And can read information from the wireless tag 18 according to each reading setting.

  As shown in FIG. 1, the RFID reader control PC 14 includes an RFID reader control unit 20, a communication unit 22, a reading setting management unit 24, a tag information storage buffer management unit 26, a tag information storage buffer 28, and a buffer monitoring unit 30. doing. The RFID reader control PC 14 implements each unit by executing RFID middleware (program) by a processor. The RFID reader control PC 14 controls the plurality of RFID readers 16 (16-1, 16-2, 16-3,...) According to the reading setting, and reads the tag ID 18 a from the wireless tag 18. The RFID reader control PC 14 temporarily stores the tag ID 18a (or information whose data format has been converted based on filtering information) read from the wireless tag 18 in the tag information storage buffer 28, and stores it in the server 12 according to the reading time interval. Send.

  The RFID reader 16 reads the tag ID 18a (tag information) recorded on the wireless tag 18 attached to the article (product or the like) in a non-contact manner. The tag ID 18a includes, for example, data representing a company code, a product item code, a product serial number, and the like in addition to a header for identifying a code system.

Next, the operation of the RFID system in this embodiment will be described.
FIG. 2 is a flowchart showing the operation of the RFID reader control PC 14.
First, the application 10a of the client PC 10 generates a reading setting in accordance with an instruction from a system user and transmits it to the RFID reader control PC 14. The reading setting includes a reading time interval, filtering information, and the like. In the RFID system according to the present embodiment, the priority of read settings is dynamically changed according to the information reading status in the RFID reader control PC 14 by transmitting a plurality of read settings with priorities to the RFID reader control PC 14. The amount of information can be adjusted. As a specific reading situation, there is a free space in the tag information storage buffer 28, and the buffer is obtained by adjusting the amount of information temporarily stored in the tag information storage buffer 28 by changing the priority of the reading setting. Avoid overflow.

  The client PC 10 transmits read setting data including a plurality of read settings with priorities to the RFID reader control PC 14 together with the read command.

  The RFID reader control PC 14 receives the read setting data from the client PC 10 through the communication unit 22 (step A1) and passes it to the RFID reader control unit 20. The RFID reader control unit 20 sends a plurality of read settings with the received read command and priority to the read setting management unit 24. The reading setting management unit 24 holds a plurality of reading settings 24a, 24b,... In order of priority (step A2).

  Next, the client PC 10 transmits a reading start command to the RFID reader control PC 14. When the RFID reader control unit 20 receives a reading start command through the communication unit 22 (Yes in Step A3), the RFID reader control unit 20 reads the RFID reader 16 according to the reading setting with the highest priority managed in the reading setting management unit 24. The start is commanded (step A4).

  The RFID reader 16 reads the tag ID 18 a (tag information) from the wireless tag 18 and sends the read tag ID 18 a to the RFID reader control unit 20 of the RFID reader control PC 14. When receiving the tag ID 18a from the RFID reader 16 (step A5), the RFID reader control unit 20 sends tag information including the tag ID 18a and the reading time to the tag information storage buffer management unit 26.

  The tag information storage buffer management unit 26 uses the tag information (tag ID and reading time, etc.) sent from the RFID reader control unit 20 according to the filtering information specified by the current reading setting. Are selected and temporarily stored in the tag information storage buffer 28 (step A7).

  Here, a specific example of a plurality of reading settings is shown. FIG. 3 shows an example of read setting data including three read settings with priorities 1, 2, and 3. In the reading setting of priority 1 with the highest priority, the reading time interval is “500 msec”, and the wireless tag 18 in which the necessary information is attached to the products of “Company A, Company B, Company C” is included in the filtering information. This tag ID 18a indicates that all tag information is required.

  Therefore, when the tag information storage buffer management unit 26 performs reading according to the reading setting of priority 1, the tag ID 18a of “Company A, Company B, Company C” is set based on “Company code”. All the data included in the tag ID 18a and the reading time are stored in the tag information storage buffer 28.

  As shown in FIG. 3, for example, for a high-priority reading setting, the reading time interval is shortened, the filtering condition is loosened to increase the amount of information of the reading result, and for a low-priority reading setting. The amount of information is set to be small by increasing the reading interval and strict filtering conditions (for example, converting the data format).

  If the RFID reader control unit 20 is not at a time corresponding to the reading time interval specified by the reading setting (step A8, No), the tag information including the tag ID 18a read by the RFID reader 16 as described above. Are sequentially stored in the tag information storage buffer 28 by the tag information storage buffer management unit 26 (steps A5 to A7).

  The RFID reader control unit 20 takes out the tag information stored in the tag information storage buffer management unit 26 when the time according to the reading time interval of the reading setting is reached, forms it, and reads it to the server 12 via the communication unit 22 (Step A9). Further, the tag information storage buffer management unit 26 deletes the tag information temporarily stored in the tag information storage buffer 28 that has been transmitted to the server 12 (step A10).

  The server 12 receives the tag information from the RFID reader control PC 14 and registers it in the database 12a.

  The RFID reader control PC 14 monitors the buffer amount of the tag information storage buffer 28 by the buffer monitoring unit 30 while reading information from the wireless tag 18, and prioritizes reading setting based on the free capacity. A reading setting changing process for changing the degree is executed (details will be described later). When the reading setting is changed by the reading setting changing process (step A11, Yes), the RFID reader control unit 20 instructs the RFID reader 16 to start reading according to the changed reading setting (step S11). A12).

  For example, when the frequency and amount of new tag information stored in the tag information storage buffer 28 is large, there is a possibility that the buffer overflows. However, in the RFID reader control PC 14 according to this embodiment, reading is performed by reading setting change processing. By lowering the setting priority, the amount of information stored in the tag information storage buffer 28 is lowered to avoid buffer overflow.

  Hereinafter, the RFID reader controller 20 performs reading according to the changed reading setting as described above, stores the tag information in the tag information storage buffer 28, and according to the reading time interval, Tag information is transmitted to the server 12 (steps A5 to A10).

  Next, the reading setting change process executed in the RFID reader control PC 14 will be described with reference to the flowchart shown in FIG.

  The RFID reader control PC 14 monitors the buffer amount of the tag information storage buffer 28 by the buffer monitoring unit 30 while the RFID reader 16 reads the tag ID 18a from the wireless tag 18 (step B1). The buffer monitoring unit 30 needs to change the reading setting by comparing the current available capacity of the tag information storage buffer 28 with preset determination reference values (first reference value and second reference value). To determine whether it is in the correct state.

The first reference value is a reference value for determining whether or not the tag information storage buffer 28 is likely to overflow. For example, information is stored in 80% of the total capacity of the buffer (the free capacity is 20%). ) Is a reference value for determining this. The second reference value is a reference value for determining whether or not the tag information storage buffer 28 has a margin. For example, information is stored in 20% of the total capacity of the buffer (the free capacity is 80%). This is a reference value for determining this.

  Here, if the free space of the tag information storage buffer 28 is less than the first reference value and it is determined that the buffer is likely to overflow (step B2, Yes), the buffer monitoring unit 30 sends the RFID reader control unit 20 A request is made to change to a reading setting with a low priority (step B3).

  The RFID reader control unit 20 requests the read setting management unit 24 for a read setting with a priority lower than the priority of the current read setting. If the reading setting management unit 24 does not manage the reading setting having a lower priority than the current reading setting (No in step B4), the reading setting management unit 24 notifies the RFID reader control unit 20 to that effect. In this case, the RFID reader control unit 20 does not change the reading setting, and continues reading with the current reading setting (No in Step B10).

  In addition, when the reading setting management unit 24 manages the reading setting having a lower priority than the current reading setting (step B4, Yes), the reading setting management unit 24 delivers the reading setting with one step lower priority to the RFID reader control unit 20. .

  The RFID reader control unit 20 changes the reading setting received from the reading setting management unit 24 to a low priority setting (step B5), and resumes reading information from the wireless tag 18 (steps A11 and A12 in FIG. 2). .

  For example, by lowering the priority of the reading setting, the data amount of the tag ID 18a read from the wireless tag 18 can be converted according to the filtering information in the reading setting to reduce the amount of information. In the example shown in FIG. 3, the tag ID 18a of the wireless tag 18 attached to the product of “Company A, Company B, Company C” as necessary information as filtering information by changing to the reading setting of the priority 2. “Company A, Company B” indicates that all tag information is required, and “Company C” indicates that only information on the number of tag information (number of tags) is required.

  In this case, when the tag ID 18a including the company code “C company” is read, the tag information storage buffer management unit 26 does not store the tag ID 18a in the tag information storage buffer 28, but instead stores the company ID “C company”. The number of tag IDs 18a including the code is counted, and this count value is stored in the tag information storage buffer 28 as the number of tag information (number of tags).

  That is, when tag IDs 18a are read from a plurality of wireless tags 18, the amount of information for storing all tag IDs 18a increases, but the amount of information is greatly reduced by converting the data format to the number of tag information (number of tags). In addition, it is possible to reduce the consumption of free space in the tag information storage buffer 28.

  The data format set as the filtering information for the reading setting is not limited to the number of tag information (number of tags) as described above, and can be arbitrarily set. For example, the common items of the tag ID 18a read from the wireless tag 18 can be grouped, and the data format can be changed to information on the number of tags included in the group.

  On the other hand, when it is determined that the free space of the tag information storage buffer 28 is larger than the second reference value and there is room in the buffer (step B6, Yes), the buffer monitoring unit 30 gives priority to the RFID reader control unit 20. Is requested to change to a high reading setting (step B7).

  The RFID reader control unit 20 requests the read setting management unit 24 for a read setting with a priority higher than the priority of the current read setting. If the reading setting management unit 24 does not manage the reading setting having a higher priority than the current reading setting (No in step B8), the reading setting management unit 24 notifies the request to the RFID reader control unit 20 to that effect. In this case, the RFID reader control unit 20 does not change the reading setting, and continues reading with the current reading setting (No in Step B10).

  In addition, when the reading setting management unit 24 manages the reading setting having a higher priority than the current reading setting (Yes in Step B8), the reading setting management unit 24 delivers the reading setting with one step higher priority to the RFID reader control unit 20. .

  The RFID reader control unit 20 changes the reading setting to the high priority reading received from the reading setting management unit 24 (step B9), and resumes reading of information from the wireless tag 18 (FIG. 2, steps A11 and A12). .

  If the free space of the tag information storage buffer 28 is between the first reference value and the second reference value (No at Step B6), reading is continued with the current reading setting.

  In this way, by transmitting a plurality of reading settings with priorities from the client PC 10 to the RFID reader control PC 14, the RFID reader control PC 14 has a priority when the tag information storage buffer 28 has a large free space. By executing reading according to a high reading setting, it is possible to notify the reading result with the reading frequency (reading time interval) and the amount of information requested by the server 12 (client PC 10). Further, in a situation where the free capacity of the tag information storage buffer 28 is reduced and there is a possibility of buffer overflow, the consumption of the capacity of the tag information storage buffer 28 is reduced by lowering the priority of the read setting to reduce the amount of information. can do.

  Even when the information amount is reduced by lowering the priority, the information that the server 12 preferentially needs is notified rather than reducing the entire information amount by completely reducing the information. It is possible. For example, for a product of “Company C”, if the information is separately read (for example, inspection) by the RFID system, the company code of “C Company” is set as the priority 2 reading setting shown in FIG. For the tag ID 18a to be included, there is no problem even if the data format is converted as only the number of tag information (number of sheets) and the number of tag information (number of sheets) is changed.

Next, a modified example of the reading setting change process will be described with reference to the flowchart shown in FIG.
In the read setting change process shown in FIG. 4, the priority of the read setting is changed stepwise according to the free capacity of the tag information storage buffer 28. In the read setting change process shown in FIG. Based on the rate of change, the priority of reading settings can be changed in multiple stages.

  While the RFID reader control PC 14 executes reading of the tag ID 18a from the wireless tag 18 by the RFID reader 16, the buffer monitoring unit 30 causes the buffer amount and the free capacity change rate (increase rate, decrease rate) of the tag information storage buffer 28. Rate) is monitored (step C1). The buffer monitoring unit 30 needs to change the reading setting by comparing the current available capacity of the tag information storage buffer 28 with preset determination reference values (first reference value and second reference value). To determine whether it is in the correct state. Note that the determination of the free space by comparison with the determination reference value is the same as in FIG.

  Here, if the free space of the tag information storage buffer 28 is less than the first reference value and it is determined that the buffer is likely to overflow (step C2, Yes), the buffer monitoring unit 30 determines the change rate of the free space and Then, a determination reference value (third reference value) with respect to a preset change rate is compared to determine whether the reading setting needs to be changed. The third reference value is a reference value for determining that the free capacity of the tag information storage buffer 28 is rapidly decreasing.

  Here, when it is determined that the decrease rate of the free capacity of the tag information storage buffer 28 is lower than the third reference value and is not rapidly decreasing (No in Step C3), the buffer monitoring unit 30 performs RFID reader control. The unit 20 is requested to change the reading setting to one level lower in priority (step C4). In this case, processing similar to the reading setting change processing shown in FIG. 4 is executed (steps C4, C5, C6).

  On the other hand, if the buffer monitoring unit 30 determines that the free capacity of the tag information storage buffer 28 is rapidly decreasing (step C3, Yes), the RFID reader control unit 20 has a plurality of priorities ( For example, two steps) Request a change to a lower reading setting (step C7).

  When the reading setting management unit 24 does not manage reading settings that are lower by a plurality of levels (step C8, No), the RFID reader controller 20 tries to change the reading setting to one level lower (step C5).

  In addition, when the reading setting management unit 24 manages reading settings that are lower by a plurality of levels (step C8, Yes), the RFID reader control unit 20 sets a plurality of readings from the reading setting management unit 24 based on the priority of the current reading setting. A reading setting with a low step priority is received and changed to this reading setting (step C9), and reading of information from the wireless tag 18 is resumed (FIG. 2, steps A11 and A12).

  That is, when the free space of the tag information storage buffer 28 decreases and the free space rapidly decreases, the tag information storage buffer 28 is further reduced in information amount by lowering the priority in a plurality of stages. The decrease in free space can be reduced.

  On the other hand, when it is determined that the free capacity of the tag information storage buffer 28 is larger than the second reference value and the buffer has room (Yes in Step C10), the buffer monitoring unit 30 determines the change rate of the free capacity and the A determination reference value (fourth reference value) for the set change rate is compared to determine whether the reading setting needs to be changed. The fourth reference value is a reference value for determining that the free capacity of the tag information storage buffer 28 is rapidly increasing.

  Here, when it is determined that the increase rate of the free capacity of the tag information storage buffer 28 is higher than the fourth reference value and has not increased rapidly (No in Step C11), the buffer monitoring unit 30 performs RFID reader control. The unit 20 is requested to change the reading setting to one level higher in priority (step C12). In this case, processing similar to the reading setting change processing shown in FIG. 4 is executed (steps C12, C13, C14).

  On the other hand, when it is determined that the free capacity of the tag information storage buffer 28 is rapidly increasing (Yes in step C11), the buffer monitoring unit 30 gives the RFID reader control unit 20 a plurality of priority levels ( For example, request to change to a higher reading setting (step C15).

  When the reading setting management unit 24 does not manage reading settings that are lower by a plurality of levels (step C8, No), the RFID reader control unit 20 tries to change the reading setting to one level higher (step C5). Alternatively, a change is made to the reading setting with the highest priority.

  In addition, when the reading setting management unit 24 manages reading settings that are lower by a plurality of levels (step C16, Yes), the RFID reader control unit 20 determines more than the reading setting management unit 24 from the priority of the current reading setting. A reading setting with a low step priority is received, changed to this reading setting (step C17), and reading of information from the wireless tag 18 is resumed (FIG. 2, steps A11 and A12).

  That is, when there is a free space in the tag information storage buffer 28 and the free space is increasing rapidly, the server 12 (client PC 10) can request more quickly by increasing the priority in multiple stages. The read result can be transmitted to the server 12 according to the read frequency and the amount of information with high priority.

  In the description of the read setting change processing described above (FIGS. 4 and 5), the priority of the current read setting is increased even though the status of the tag information storage buffer 28 requires the read setting to be changed. If it cannot be lowered, the reading is continued with the current reading setting. In such a case, the RFID reader control PC 14 (RFID reader control unit 20) may notify the client PC 10 or the server 12 to that effect. As a result, a new reading setting can be transmitted from the client PC 10, or data indicating that a buffer overflow may have occurred in the server 12 can be registered in the database 12a as a history. .

  In the above description, the RFID tag reader is realized by executing RFID middleware (program) in the RFID reader control PC 14. However, the RFID reader 16 can also realize the RFID tag reader. That is, the RFID reader 16 executes a program that realizes the same function as the RFID middleware (program) described above, thereby realizing the same function as the RFID reader control PC 14 described above.

  In the above description, the capacity of the tag information storage buffer 28 of the RFID reader control PC 14 is monitored and the read setting priority is changed based on the free capacity. The priority of the reading setting may be changed based on the situation.

  For example, the network traffic for transmitting information from the RFID reader control PC 14 to the server 12 is monitored by the communication unit 22, and in a situation where the traffic is lower than the reference value and there is a margin, reading is performed by increasing the priority of the reading setting. In a situation where the congestion is higher than the reference value, the reading setting priority may be raised and the reading may be executed. As a result, the server 12 can reduce the delay in acquiring information from the RFID reader control PC 14 due to the increase in traffic.

  Furthermore, in the above-described embodiment, the RFID middleware (wireless tag reading program) for realizing each function for carrying out the invention has been recorded in the RFID reader control PC 14 in advance. However, the present invention is not limited to this. The above program may be downloaded from the network to the RFID reader control PC 14, or a similar program stored in a recording medium may be installed in the RFID reader control PC 14. The recording medium may be any form as long as the recording medium can store the program and can be read by the apparatus, such as a CD-ROM. In addition, the function obtained by installing or downloading in advance may be realized in cooperation with the OS or the like inside the apparatus.

  In addition, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, the constituent elements over different embodiments may be combined.

  DESCRIPTION OF SYMBOLS 10 ... Client PC, 12 ... Server, 14 ... RFID reader control PC, 16 ... RFID reader, 20 ... RFID reader control part, 22 ... Communication part, 24 ... Read setting management part, 24a, 24b ... Read setting data, 26 ... Tag information storage buffer management unit, 28... Tag information storage buffer, 30.

JP-A-2005-005836 JP 2008-191947 A

Claims (6)

In a wireless tag reader that reads information of a wireless tag attached to an article,
Reading setting management means for managing a plurality of reading settings indicating the reading contents of the information;
Storage means for storing information read from the wireless tag;
Monitoring means for monitoring the free capacity of the storage means;
The reading setting for reading information from the wireless tag is changed based on the free capacity of the storage means monitored by the monitoring means, and the information is read from the wireless tag according to the reading setting and stored in the storage means. A wireless tag reader comprising a control means. The read setting management means manages the plurality of read settings given priority in the order of read settings that reduce the amount of information stored in the storage means,
The control means includes
Wherein when the free space that is monitoring becomes less than the first reference value, to change the lower priority the reading set by the monitoring unit,
Claims, characterized in that reading said if storage space is that it is now more than the second reference value is monitored, the information from the wireless tag is changed to a higher priority the reading set by the monitoring means The wireless tag reader according to 1.   The wireless tag reader according to claim 2, wherein the control unit changes the priority of the reading setting for each step. The control means includes
Wherein the monitoring means, when the free space is less than the first reference value and the change rate per unit of the free space is reduced time is monitored that is greater than a third reference value, the priority Change to the reading setting lower by several steps,
Wherein the monitoring means, when the free space becomes greater than the second reference value and the change rate per unit of the free space increases time is monitored that is greater than the fourth reference value, the priority The RFID tag reader according to claim 2, wherein the reading setting is changed to a reading setting higher by a plurality of levels. Further comprising conversion means for converting the information read from the wireless tag into the data format based on the designation of the data format included in the reading setting;
2. The wireless tag reading apparatus according to claim 1, wherein the control means stores the information whose data format is converted by the conversion means in the storage means. A computer that reads the information of the wireless tag attached to the article,
Reading setting management means for managing a plurality of reading settings indicating the reading contents of the information;
Monitoring means for monitoring the free capacity of the storage means for storing information read from the wireless tag;
The reading setting for reading information from the wireless tag is changed based on the free capacity of the storage means monitored by the monitoring means, and the information is read from the wireless tag according to the reading setting and stored in the storage means. A wireless tag reading program for functioning as a control means.

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