Information reading system and specific reading device
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- DENSO WAVE INC
- Filing Date
- 2022-12-26
- Publication Date
- 2026-08-05
Smart Images
Figure 0007900671000001 
Figure 0007900671000002 
Figure 0007900671000003
Abstract
Description
Technical Field
[0001] This specification discloses a technique for reading measurement values from each of a plurality of sensor tags.
Background Art
[0002] In a situation where a plurality of sensor tags are arranged over a wide area, it may not be possible for a single reading device to read measurement values from all the sensor tags. To address such a situation, it is assumed that two or more reading devices are used. However, when using two or more reading devices, it is necessary to synchronize the counters built into each of the two or more reading devices with each other.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] As a method for synchronizing the counters built into each of two or more reading devices with each other, for example, it is assumed that a reference signal transmission device as shown in Patent Document 1 is connected to two or more reading devices. Each of the two or more reading devices resets its counter using the pulse signal transmitted from the reference signal transmission device to each reading device. However, with this method, each of the two or more reading devices needs to be equipped with a mechanism for connecting to the reference signal transmission device. This specification provides a technique for easily synchronizing the counters in a reading device without providing such a mechanism.
Means for Solving the Problems
[0005] The information reading system disclosed herein comprises a first reading device, a second reading device, and a plurality of tags, wherein each of the first and second reading devices includes a device counter, an antenna capable of repeatedly transmitting radio waves for reading information from each of the plurality of tags and receiving response waves to said radio waves from each of the plurality of tags, and a reset unit for resetting the device counter, and each of the plurality of tags includes an antenna capable of receiving the radio waves and transmitting the response waves, and an assigning unit for assigning the information to the response waves, and the plurality of The tag includes a plurality of sensor tags configured to assign measured values output from sensors as information to the response wave, and a specific tag, wherein the specific tag is installed within a first overlapping range where the first range readable by the first reader and the second range readable by the second reader overlap, and the specific tag is configured to sporadically transmit a specific response wave while repeatedly transmitting the response wave, and both the reset unit of the first reader and the reset unit of the second reader reset the device counter when they receive the specific response wave from the specific tag.
[0006] According to the above configuration, the device counter of the first reader and the device counter of the second reader can be synchronized based on a specific response wave transmitted from a specific tag installed in the first overlapping range. The counters within the reader devices can be easily synchronized without requiring any special mechanisms in the first and second reader devices.
[0007] Both the antenna of the first reader and the antenna of the second reader transmit search radio waves for searching for tags within the first overlapping range, and either the first reader or the second reader may further include a selection unit that, when two or more tags are found within the first overlapping range, selects from among the two or more tags the tag with the highest received intensity of the response wave to the search radio wave and the highest received frequency of the response wave to the search radio wave as the specific tag.
[0008] According to the above configuration, the optimal tag can be selected as the designated tag from among two or more tags using the received signal strength or frequency.
[0009] If an abnormality occurs in the first tag after the first tag has been selected as the specific tag, the selection unit may, in place of the first tag, select the second tag from the two or more tags as the specific tag.
[0010] With the above configuration, even if an abnormality occurs in the first tag selected as the specific tag, the second tag will be newly selected as the specific tag. Even if an abnormality occurs in the first tag, the synchronization of the counters in the reader can continue.
[0011] The information reading system further comprises a third reading device having the same configuration as the first reading device, the second reading device comprises two device counters, the plurality of tags include two specific tags, one of the two specific tags is installed within the first overlapping range, the other of the two specific tags is installed within the second overlapping range where the second range readable by the second reading device and the third range readable by the third reading device overlap, and the reset unit of the first reading device, when it receives the specific response wave from one of the specific tags, the device counter of the first reading device The reset unit of the second reader device may reset the device counter when it receives the specific response wave from one of the specific tags, resetting one of the two device counters but not the other of the two device counters; the reset unit of the second reader device may reset the other device counter but not the first device counter when it receives the specific response wave from the other specific tag; and the reset unit of the third reader device may reset the device counter of the third reader device when it receives the specific response wave from the other specific tag.
[0012] According to the above configuration, a third reader device is added in addition to the two existing readers. This allows for the placement of sensor tags over a wider area than with just two readers. The second reader device also includes two device counters. The device counter of the first reader device and one of the device counters of the second reader device can be synchronized based on a specific response wave transmitted from one specific tag located within the first overlapping area. Furthermore, the other device counter of the second reader device and the device counter of the third reader device can be synchronized based on a specific response wave transmitted from the other specific tag located within the second overlapping area.
[0013] The specified tag includes a tag counter that counts the number of times the response wave is transmitted, and the specified tag is configured to be able to assign the counter value output from the tag counter to the response wave as the information, and the specified response wave may include a value indicating a predetermined number of times as the counter value.
[0014] According to the above configuration, response waves assigned a predetermined number of times are transmitted sporadically, and response waves assigned a predetermined number of times can be used as a specific response wave.
[0015] The aforementioned specific tag may be a sensor tag.
[0016] For example, consider a comparative example where the specific tag is a tag that does not assign sensor measurements. In this comparative example, it is necessary to prepare a separate tag other than the sensor tag as the specific tag. In contrast, with the above configuration, the specific tag can be used in conjunction with the sensor tag, eliminating the need to prepare a separate tag other than the sensor tag.
[0017] The information reading system further includes an analyzer. Both the first reading device and the second reading device further include a transmitting unit that attaches the counter value output from the device counter to the measurement value included in the response wave received from the plurality of tags and transmits the result to the analyzer. The analyzer may analyze the plurality of measurement values measured by the plurality of sensor tags based on the counter value attached to the measurement value received from either the first reading device or the second reading device.
[0018] According to the above configuration, the counter value attached to the measurement value obtained from the first reading device and the counter value attached to the measurement value obtained from the second reading device are synchronized with each other. The analyzer can synchronize all the measurement values obtained from the first reading device and the second reading device by using the synchronized counter values and accurately analyze all the measurement values.
[0019] The control method for realizing the above information reading system, the computer program for realizing the above information reading system, and the computer-readable storage medium storing the computer program are also novel and useful. Also, the above first reading device, second reading device, and third reading device itself are also novel and useful.
Brief Description of the Drawings
[0020] [Figure 1] It is a conceptual diagram of an information reading system according to the first and second embodiments. [Figure 2] It is a block diagram of an information reading system. [Figure 3] It is a flowchart showing the processing of a reading device. [Figure 4] It is a sequence diagram showing a specific case. [Figure 5] It is a conceptual diagram of an information reading system according to the third embodiment. [Figure 6] It is a block diagram of an information reading device. [Figure 7] It is a flowchart showing the processing of a reading device. [Figure 8] It is a sequence diagram showing a specific case. [Figure 9] It is a sequence diagram showing the continuation of FIG. 8.
Embodiments for Carrying Out the Invention
[0021] (First Embodiment) (Configuration of the Information Reading System 2; FIGS. 1 and 2) The information reading system 2 includes a plurality of sensor tags 10, a reading device 100, a reading device 200, and a terminal device 500. The reading devices 100 and 200 are devices that read information stored in Radio Frequency Identifier (RFID) tags. The plurality of sensor tags 10 are installed on the surface of the object 4. The object 4 is, for example, a structure such as a bridge, a building, or a road. In FIG. 1, two sensor tags are labeled, and the labeling of the remaining sensor tags is omitted. In a modified example, the object 4 is not limited to the above-mentioned structures, and may be, for example, a vehicle (e.g., a vehicle body, an axle), equipment in a factory, or an aircraft (e.g., a helicopter blade).
[0022] Each of the plurality of sensor tags 10 is an RFID tag provided with a sensor 40 (see FIG. 2) for measuring the vibration of the object 4. Each sensor tag 10 is configured to be able to transmit a response wave to various radio waves transmitted from a reading device (e.g., 100). For example, the measured value output from the sensor 40, that is, the vibration value, is added to the response wave. Thereby, the reading device acquires the vibration value at the location where the sensor tag 10 is installed. In a modified example, the physical quantity measured by the sensor 40 is not limited to the vibration value, and may be, for example, acceleration, temperature, humidity, carbon dioxide concentration, etc.
[0023] The dashed line in Figure 1 indicates the reading range 102, which represents the range that the reading device 100 can read. In other words, the reading device 100 can receive response waves from sensor tags 10 located within the reading range 102, but cannot receive response waves from sensor tags 10 located outside the reading range 102. The dashed line in Figure 1 indicates the reading range 202, which represents the range that the reading device 200 can read. As shown in Figure 1, the reading range 102 and the reading range 202 overlap. In the following, sensor tags 10 located in the overlapping range 102a, which is the area where the reading ranges 102 and 202 overlap, will be referred to as duplicate tags 10a. In the case shown in Figure 1, there is one duplicate tag 10a in the overlapping range 102a. The number of duplicate tags 10a is not limited to one; there may be two or more.
[0024] The reading devices 100 and 200 are stationary devices. The reading devices 100 and 200 are connected to the terminal device 500 by wire or wireless connection. The reading devices 100 and 200 transmit vibration values acquired from the sensor tag 10 to the terminal device 500.
[0025] (Configuration of sensor tag 10; Figure 2) The sensor tag 10 comprises an antenna 12, a demodulation unit 14, a modulation unit 16, an assignment unit 30, and a sensor 40. The antenna 12 receives radio waves from a reader (e.g., 100) and transmits a response wave. The demodulation unit 14 is a circuit that demodulates the radio waves from the reader into a signal that can be interpreted by the assignment unit 30 and supplies the signal to the assignment unit 30. The modulation unit 16 is a circuit that modulates the signal from the assignment unit 30 into radio waves and supplies the radio waves to the antenna 12. The assignment unit 30 is a circuit that processes the signal from the demodulation unit 14. The sensor 40 is connected to the assignment unit 30. The demodulation unit 14, modulation unit 16, assignment unit 30, and sensor 40 are powered by the radio waves received by the antenna 12.
[0026] The tag assignment unit 30 includes a tag counter 32. Hereinafter, the value output from the tag counter 32 will be referred to as the tag counter value. The tag counter value is an integer between 0 and 255. The tag counter 32 increments the tag counter value each time a response wave is transmitted. When the tag counter value is at its maximum of "255" and a response wave is transmitted, the tag counter value returns to its initial value of "0". Note that the maximum value of "255" and the minimum value of "0" for the tag counter value are merely examples.
[0027] The information assignment unit 30 assigns various information to the signal acquired from the demodulation unit 14 and supplies it to the modulation unit 16. As a result, the response wave with various information assigned to it is transmitted from the antenna 12 to the reading device. The information assigned by the information assignment unit 30 is, for example, an ID that identifies the sensor tag 10, a tag counter value, and a vibration value which is the output value of the sensor 40.
[0028] (Configuration of reading devices 100 and 200; Figure 2) The reading devices 100 and 200 have the same configuration. Each of the reading devices 100 and 200 includes an antenna 112, a processing unit 130, and an external interface 114. Hereafter, the interface will be referred to as "I / F". The reading device 100 will be described below.
[0029] Antenna 112 performs the transmission of various radio waves and the reception of response waves to those radio waves. For example, antenna 112 transmits a reading radio wave, which is a radio wave for reading information from the sensor tag 10, to the sensor tag 10, and receives a response wave from the sensor tag 10 to the reading radio wave. Processing unit 130 is a circuit that processes various information. Processing unit 130 includes, for example, a CPU and memory, and the CPU performs various processes according to the program stored in memory. External I / F 114 is an I / F for performing communication with external devices and is connected to terminal device 500.
[0030] The processing unit 130 comprises a plurality of demodulation units 134, a plurality of counter assignment units 136, a reset unit 140, and a device counter 142. Although not shown in the figures, the processing unit 130 also includes a modulation unit that generates radio waves and supplies them to the antenna 112. Each unit may be implemented, for example, by a program in the memory of the processing unit 130, or by hardware such as logic circuits.
[0031] The device counter 142 is a timer that counts time. The reset unit 140 is connected to the device counter 142. The reset unit 140 resets the count of the device counter 142 back to 0 seconds.
[0032] The number of demodulation units 134 corresponds to the number of sensor tags 10 that the reader 100 can read. One counter assignment unit 136 is connected to one demodulation unit 134. The demodulation unit 134 demodulates the response wave received from the sensor tag 10 into a signal that the counter assignment unit 136 can interpret, and supplies the signal to the counter assignment unit 136.
[0033] Each of the multiple counter assignment units 136 is connected to the device counter 142. The counter assignment unit 136 assigns a value output from the device counter 142 to the signal acquired from the demodulation unit 134. Hereafter, the value output from the device counter 142 will be referred to as the device counter value.
[0034] Furthermore, each of the multiple counter assignment units 136 is connected to an external I / F 114. The signals processed by the counter assignment units 136 are supplied to the external I / F 114 and transmitted to an external terminal device 500.
[0035] Furthermore, the reset unit 140 is connected to a specific demodulation unit 134a among the multiple demodulation units 134 that demodulates the radio waves from the duplicate tag 10a.
[0036] (Configuration of terminal device 500; Figure 2) The terminal device 500 is a laptop PC, notebook PC, smartphone, server, etc. The terminal device 500 has an analysis program 510 installed for analyzing the information of the sensor tags 10 read by the readers 100 and 200. The analysis program 510 is provided, for example, by the vendor of the readers 100 and 200. In a modified example, the analysis program 510 may be provided by a different business operator than the said vendor.
[0037] The analysis program 510 uses the device counter values of the readers 100 and 200 to arrange the vibration values measured by multiple sensor tags 10 in chronological order. This allows for accurate identification of vibrations occurring within the object 4. By analyzing the vibrations occurring within the object 4, it is possible to identify vulnerable areas (e.g., damaged areas) of the object 4. Furthermore, in order to arrange the vibration values measured by multiple sensor tags 10 in chronological order, the device counter values of the readers 100 and 200 must be synchronized.
[0038] (Processing by reading devices 100 and 200; Figure 3) Referring to Figure 3, the processing performed by the processing unit 130 will be described. The processing in Figure 3 is triggered when a start instruction to begin the processing in Figure 3 is input to the reading device 100 or 200. This start instruction may be input by operating the operation unit of the reading device 100 or 200, or by receiving a signal indicating a start instruction from the terminal device 500.
[0039] In S10, the processing unit 130 determines whether or not there is one or more duplicate tags 10a within the overlapping range 102a of the reader 100 and the reader 200. Specifically, the processing unit 130 transmits a search radio wave to the outside via the antenna 112 to search for sensor tags 10 within the reading range. Each sensor tag 10 transmits a response wave to the search radio wave with its own ID attached. Note that the measurement value of the sensor 40 is not attached to the response wave to the search radio wave. If there are duplicate tags 10a within the overlapping range 102a, among the multiple response waves received by one of the reader 100 and 200, there is a response wave with the same ID as the response wave attached to the response wave received by the other reader 100 and 200. The processing unit 130 determines that there is one or more duplicate tags 10a within the overlapping range 102a when response waves with the same ID are received between the reader 100 and the reader 200.
[0040] The decision in S10 requires a comparison between multiple response waves received by the reader 100 and multiple response waves received by the reader 200. This comparison is performed, for example, by the reader 100. In this case, the multiple response waves received by the reader 200 are supplied to the reader 100. Then, information indicating the comparison result by the reader 100 is supplied from the reader 100 to the reader 200. In a modified example, this comparison may be performed, for example, by the terminal device 500. In this case, both the multiple response waves received by the reader 100 and the multiple response waves received by the reader 200 are transmitted to the terminal device 500. Then, information indicating the comparison result by the terminal device 500 is transmitted from the terminal device 500 to both the reader 100 and the reader 200.
[0041] If the processing unit 130 determines that there are no duplicate tags 10a within the overlapping range 102a (NO in S10), it returns to the determination in S10. In this case, the user adjusts the position of the sensor tag 10 so that it is placed within the overlapping range 102a.
[0042] Furthermore, if the processing unit 130 determines that there is one or more duplicate tags 10a within the overlap range 102a (YES in S10), it proceeds to S12. In S12, the processing unit 130 selects one duplicate tag 10a from among the one or more duplicate tags 10a that has the highest signal strength of the response wave. Then, the processing unit 130 sets the demodulation unit 134a for the selected duplicate tag 10a. Here, the signal strength is, for example, RSSI. Note that if only one duplicate tag 10a is found in S10, the process in S12 is skipped, and the demodulation unit 134a is automatically set for that one duplicate tag 10a. According to the process in S12, it is possible to select the most reliable and optimal duplicate tag 10a from among two or more duplicate tags 10a using signal strength.
[0043] In S20, following S12, the processing unit 130 transmits a radio wave with a start command attached to it to the outside via the antenna 112. The start command is a command that changes the state of the sensor tag 10 from a non-measurement state to a measurement state. In the non-measurement state, the attachment unit 30 does not attach the measured value of the sensor 40 to the response wave. On the other hand, in the measurement state, the attachment unit 30 attaches the measured value of the sensor 40 to the response wave. When the sensor tag 10 receives a radio wave with a start command attached to it from the reader, it changes the state of the sensor tag 10 from a non-measurement state to a measurement state.
[0044] Furthermore, when the processing unit 130 transmits a radio wave to which a start command has been attached, it begins to repeatedly transmit a reading radio wave via the antenna 112. The reading radio wave is a radio wave used to read the measured value of the sensor tag 10. In other words, the reading device begins reading the measured value of the sensor 40 through the processing in S20.
[0045] In S22, the processing unit 130 starts counting using the device counter 142. In S30, the processing unit 130 monitors for the reception of response waves to the reading radio waves that were transmitted in S20. For a single transmission of a reading radio wave, the processing unit 130 can simultaneously receive multiple response waves from multiple sensor tags 10 that are within the reading range (e.g., 102) that the reading device can read. The reading device sets one demodulation unit 134 for each sensor tag 10.
[0046] If the processing unit 130 does not receive a response wave to the read radio wave (NO in S30), it skips the processing in S32 to S42 and proceeds to S50. On the other hand, if the processing unit 130 receives a response wave to the read radio wave (YES in S30), it proceeds to S32. Here, the response wave to the read radio wave is associated with an ID that identifies the source sensor tag 10 of the response wave, the measured value of the sensor 40 of the source sensor tag 10, and the tag counter value of the source sensor tag 10.
[0047] In S32, the processing unit 130 uses multiple demodulation units 134 to demodulate the multiple response waves received in S22, and obtains a signal from each response wave that includes the ID, measured value, and tag counter value.
[0048] In S34, the processing unit 130 uses multiple counter assignment units 136 to assign the current device counter value to the ID and measured value obtained from each response wave, and generates multiple data to be transmitted to the terminal device 500.
[0049] In S36, the processing unit 130 transmits the multiple data generated in S34 to the terminal device 500 via the external I / F 114.
[0050] In the following step S40, the processing unit 130 determines whether the tag counter value assigned to the response wave received from the duplicate tag 10a, that is, the tag counter value obtained from the demodulation unit 134a corresponding to the duplicate tag 10a, indicates "0". If the processing unit 130 determines that the tag counter value does not indicate "0" (NO in S40), it skips S42 and proceeds to S50. On the other hand, if the processing unit 130 determines that the tag counter value indicates "0" (YES in S40), it proceeds to S42.
[0051] In S42, the processing unit 130 uses the reset unit 140 to reset the device counter 142. When S42 is finished, the processing unit 130 proceeds to S50.
[0052] In S50, the processing unit 130 determines whether or not a termination instruction to end the process shown in Figure 3 is input to the reading device. This termination instruction may be input by operating the operation units of the reading devices 100 and 200, or by receiving a signal indicating a termination instruction from the terminal device 500.
[0053] When the processing unit 130 determines that a termination instruction has been input to the reader (YES in S50), it terminates the process shown in Figure 3 while transmitting a radio wave with the termination command attached to it to the outside. The termination command is a command that changes the state of the sensor tag 10 from the measurement state to the non-measurement state. When the sensor tag 10 receives a radio wave with the termination command attached from the reader, it changes the state of the sensor tag 10 from the measurement state to the non-measurement state.
[0054] Furthermore, if the processing unit 130 determines that no termination instruction has been input to the reading device (NO in S50), it returns to monitoring in S30. In other words, the processing unit 130 continues to transmit the reading radio waves until a termination instruction is input to the reading device.
[0055] In addition, it is conceivable that after the first tag is selected from among two or more duplicate tags 10a in S12, an abnormality may occur in the first tag. In this case, the processing unit 130 selects the second tag from among the two or more duplicate tags 10a instead of the first tag. Then, the processing unit 130 uses the tag counter value attached to the response wave from the second tag to determine whether or not to reset the device counter (S40). With this configuration, even if an abnormality occurs in the first tag, the synchronization of the counter in the reader can be continued. In the modified example, the above process of selecting the second tag instead of the first tag does not need to be performed.
[0056] (Specific case; Figure 4) In this case, one duplicate tag 10a is found within the overlap range 102a (YES in S10 of Figure 3). This single duplicate tag 10a is identified by the ID "tg1". As a result, the processing from S20 onwards in Figure 3 is executed in both the reader devices 100 and 200.
[0057] In T10A, the reader 100 transmits a reading signal to the duplicate tag 10a, and in T10B, the reader 200 transmits a reading signal to the duplicate tag 10a (S20). Note that the reading signal from reader 100 reaches all sensor tags 10 within the reading range 102, and the reading signal from reader 200 reaches all sensor tags 10 within the reading range 202. In Figure 4, the duplicate tag 10a is shown among all the sensor tags 10 installed on the surface of target 4, and the remaining sensor tags 10 are not shown.
[0058] When the duplicate tag 10a receives reading signals from the respective reading devices 100 and 200 at T10A and T10B, it acquires the measured value V1 from the sensor 40 at T12. At T14, the duplicate tag 10a acquires the current tag counter value "0" from the tag counter 32. Then, at T16A and T16B, the duplicate tag 10a transmits a response wave to the respective reading devices 100 and 200, which is assigned the ID "tg1", the measured value V1, and the tag counter value "0". When the response wave is transmitted, the tag counter value is incremented from "0" to "1".
[0059] When the reader 100 receives a response wave from the duplicate tag 10a at T16A, it demodulates the response wave at T20A and obtains a signal from the response wave that includes the ID "tg1", the measured value V1, and the tag counter value "0" (S32). The reader 100 then assigns the current device counter value C1 to the ID "tg1" and the measured value V1 (S34). As a result, data including the ID "tg1", the measured value V1, and the device counter value C1 is generated.
[0060] In T22A, the reader 100 transmits the data generated in T20A to the terminal device 500. In this case, the reader 100 receives response waves not only from the duplicate tag 10a but also from all the remaining sensor tags 10 within the reading range 102. Therefore, in T22A, the reader 100 also transmits data including the measured values measured by the remaining sensor tags 10 to the terminal device 500. The data corresponding to the remaining sensor tags 10 includes an ID different from ID "tg1" but also includes the same device counter value C1.
[0061] Furthermore, the reader 100 determines in T16A that the tag counter value attached to the response wave received from the duplicate tag 10a is "0" (YES in S40). As a result, the reader 100 resets its device counter 142 in T24A (S42).
[0062] Furthermore, the reader 200 also executes the processing T16B to T24B, similar to the T16A to T24A processes of the reader 100. Here, in T20B, the reader 200 assigns the current device counter value C2 of the reader 200 to the ID "tg1" and the measured value V1. The device counter value C2 is different from the device counter value C1. This is because, at this point, the device counter 142 of the reader 100 and the device counter 142 of the reader 200 are not synchronized.
[0063] Furthermore, in T24B, the reader 200 resets its device counter 142 (S42). Since readers 100 and 200 receive response waves from the duplicate tag 10a at the same time in T16A and T16B, T24A and T24B are also executed at the same time. That is, readers 100 and 200 reset their device counters 142 at the same time. As a result, the device counter 142 of reader 100 and the device counter 142 of reader 200 are synchronized.
[0064] Furthermore, at T22A, terminal device 500 receives data including the device counter value C1 from reader device 100, and at T22B, receives data including the device counter value C2 from reader device 200. As described above, the device counter value C2 is different from the device counter value C1. Therefore, at T30, terminal device 500 determines that the device counter 142 of reader device 100 and the device counter 142 of reader device 200 are not yet synchronized, and does not analyze the data received at T22A and T22B. In other words, the measured value V1 acquired at T14 is not used for analysis.
[0065] In this case, readers 100 and 200 repeatedly transmit reading radio waves. T40A to T52A and T40B to T52B are the same as T10A to T22A and T10B to T22B, except that the measured value V2 is acquired, the tag counter value is "1", and the device counter value of reader 100 and the device counter value of reader 200 are the same C3. Therefore, in T60, terminal device 500 determines that the device counter 142 of reader 100 and the device counter 142 of reader 200 are synchronized. Using the synchronized counter value C3, terminal device 500 synchronizes all measured values acquired from reader 100 and reader 200, that is, all measured values corresponding to all sensor tags 10 installed on the surface of target 4. This allows all measured values to be accurately analyzed.
[0066] (Effects of this embodiment) According to the configuration of this embodiment, the device counter 142 of the reader 100 and the device counter 142 of the reader 200 can be synchronized based on the response wave transmitted from the duplicate tag 10a installed in the overlapping area 102a where the reading range 102 of the reader 100 and the reading range of the reader 200 overlap. The counters within the reader devices can be easily synchronized without providing any special mechanisms in the reader devices 100 and 200.
[0067] Furthermore, according to this embodiment, response waves with a tag counter value of "0" are sporadically transmitted from the duplicate tag 10a. Specifically, a response wave with a tag counter value of "0" is transmitted only when the minimum value is "0" within the range of a minimum value of "0" to a maximum value of "255". The sporadically transmitted response waves for resetting the device counter 142 can be realized using the output value of the tag counter 32.
[0068] Furthermore, a comparative example can be considered in which the duplicate tag 10a is a simple tag that does not have a sensor 40. In this comparative example, it is necessary to separately prepare a tag other than the sensor tag 10 as the duplicate tag 10a. In contrast, according to the configuration of this embodiment, the duplicate tag 10a can be used interchangeably with the sensor tag 10, and it is not necessary to separately prepare a tag other than the sensor tag 10. Note that the above comparative example may be adopted in the modified example.
[0069] (Correspondence) Information reading system 2 is an example of an "information reading system". Multiple sensor tags 10, antenna 12, tag assignment unit 30, tag counter 32, and sensor 40 are examples of "multiple tags", "antenna", "tag assignment unit", "tag counter", and "sensor", respectively. Reading device 100 and reading device 200 are examples of a "first reading device" and a "second reading device", respectively. Antenna 112, device counter 142, and reset unit 140 are examples of an "antenna", "device counter", and "reset unit", respectively. Duplicate tag 10a, reading range 102, and reading range 202 are examples of a "specific tag", "first range", and "second range", respectively. Duplicate range 102a is an example of a "first duplicate range". Response wave containing tag counter value "0" and tag counter value "0" are examples of a "specific response wave" and a "predetermined number of times", respectively. Terminal device 500 is an example of an "analysis device". The processing unit 130 that executes the process in S12 and the processing unit 130 that executes the process in S36 in Figure 3 are examples of the "selection unit" and the "transmission unit," respectively.
[0070] (Second example) (Processing by reading devices 100 and 200; Figure 3) This embodiment is the same as the first embodiment, except that some of the processing of the reading devices 100 and 200 differs. In this embodiment, the search signal is transmitted multiple times in S10 in Figure 3. Then, in S12, the processing unit 130 selects one duplicate tag 10a from among one or more duplicate tags 10a that has the highest reception frequency of the response wave. By utilizing the reception frequency, it is possible to select one highly reliable and optimal duplicate tag 10a from two or more duplicate tags 10a.
[0071] (Third embodiment) (Configuration of Information Reading System 2; Figure 5) The information reading system 2 of this embodiment includes a reading device 300 in addition to reading devices 100 and 200. As shown in Figure 5, the reading device 300 is positioned between the reading devices 100 and 200. The reading device 300 is connected to the terminal device 500.
[0072] The dashed line in Figure 5 indicates the reading range 302, which represents the range that the reader 300 can read. As shown in Figure 5, the reading range 102 of reader 100 and the reading range 302 of reader 300 overlap. Similarly, the reading range 202 of reader 200 and the reading range 302 of reader 300 also overlap. Hereafter, sensor tags 10 located in the first overlapping range 302b, which is the overlapping range of reading range 102 and reading range 302, and sensor tags 10 located in the second overlapping range 302c, which is the overlapping range of reading range 202 and reading range 302, will be referred to as the first overlapping tag 10b and the second overlapping tag 10c, respectively.
[0073] (Configuration of the reading device 300; Figure 6) Unlike the reading device 100 of the first embodiment, the reading device 300 includes two device counters 142a and 142b. Specifically, the processing unit 130 includes a first device counter 142b, a second device counter 142c, a first reset unit 140b, and a second reset unit 140c. The first reset unit 140b is connected to the first device counter 142b. The first reset unit 140b resets the count of the first device counter 142b. The second reset unit 140c is connected to the second device counter 142c. The second reset unit 140c resets the count of the second device counter 142c. In the following, the value output from the first device counter 142b and the value output from the second device counter 142c will be referred to as the first device counter value and the second device counter value, respectively.
[0074] Furthermore, the first reset unit 140b is connected to a specific demodulation unit 134b among the multiple demodulation units 134 that demodulates the radio waves from the first duplicate tag 10b. Also, the second reset unit 140c is connected to a specific demodulation unit 134c among the multiple demodulation units 134 that demodulates the radio waves from the second duplicate tag 10c.
[0075] The reading devices 100 and 200 in this embodiment have the same configuration as the reading devices 100 and 200 in the first embodiment. In a modified example, at least one of the reading devices 100 and 200 in this embodiment may have the same configuration as the reading device 300.
[0076] (Processing by the reading device; Figure 3) Referring to Figure 7, the processing performed by the processing unit 130 of the reading device 300 will be described. The trigger for the processing in Figure 7 is the same as the trigger for the processing in Figure 3.
[0077] In S110, the processing unit 130 determines whether or not the first duplicate tag 10b exists within the first overlap range 302b between the readers 100 and 300. The specific processing method is the same as in S10 in Figure 3. If the processing unit 130 determines that the first duplicate tag 10b exists (YES in S110), it proceeds to S112. On the other hand, if the processing unit 130 determines that the first duplicate tag 10b does not exist (NO in S110), it returns to the determination in S110.
[0078] In S112, the processing unit 130 determines whether or not a second duplicate tag 10c exists within the second overlap range 302c between the readers 300 and 200. The specific processing method is the same as in S10 in Figure 3. If the processing unit 130 determines that a second duplicate tag 10c exists (YES in S112), it proceeds to S120. On the other hand, if the processing unit 130 determines that a second duplicate tag 10c does not exist (NO in S112), it returns to the determination in S112.
[0079] S120 to S132 are the same as S20 to S32 in Figure 3. S134 is the same as S34 in Figure 3, except that both the first device counter value and the second device counter value are assigned. S136 is the same as S36 in Figure 3. In S140, the processing unit 130 determines whether the tag counter value assigned to the response wave received from the first duplicate tag 10b indicates "0". If the processing unit 130 determines that the tag counter value indicates "0" (YES in S140), it proceeds to S142.
[0080] In S142, the processing unit 130 uses the first reset unit 140b to reset the first device counter 142b.
[0081] Furthermore, if the processing unit 130 determines that the tag counter value assigned to the response wave received from the first duplicate tag 10b is not "0" (NO in S140), it skips S142 and proceeds to S144. S144 is the same as S140 except that the tag counter value assigned to the response wave received from the second duplicate tag 10c is used. If the processing unit 130 determines that the tag counter value is "0" (YES in S144), it proceeds to S146.
[0082] In S146, the processing unit 130 uses the second reset unit 140c to reset the second device counter 142c.
[0083] Furthermore, the processing unit 130 proceeds to S150 if S142 is completed, if S146 is completed, or if it is determined in S144 that the tag counter value does not show "0" (NO in S144). S150 is the same as S50 in Figure 3.
[0084] (Specific cases; Figures 8 and 9) In this embodiment, the response waves from duplicate tags 10b and 10a are used to reset the device counter in the reader. Here, the first duplicate tag 10b is identified by ID "tg2", and the second duplicate tag 10c is identified by ID "tg3".
[0085] In the reading device 300 of this embodiment, both of the two device counters 142b and 142c are reset. In the case of Figure 8, the device counter 142 of the reading device 100 and the first device counter 142b of the reading device 300 have already been reset. That is, at the beginning of Figure 8, the device counter 142 of the reading device 100 and the first device counter 142b are synchronized, while the device counter 142 of the reading device 200 and the second device counter 142c are not yet synchronized.
[0086] In T110A to T11D, each reader device 100 to 300 transmits a reading radio wave to the outside. T112B, T114B, T116A, and T116B are the same as T42, T44, T46A, and T46B in Figure 4, except that the measured value V3 acquired in the first duplicate tag 10b is used and the ID "tg2" of the first duplicate tag 10b is assigned to the response wave. Also, T112C, T114C, T116C, and T116D are the same as T42, T44, T46A, and T46B in Figure 4, except that the measured value V4 is acquired in the second duplicate tag 10c and the ID "tg3" of the second duplicate tag 10c is assigned to the response wave.
[0087] T120A is the same as T50A in Figure 3, except that the device counter value C4 of the reader 100 is assigned to it. In T122A, the reader 100 transmits data including the ID "tg2", the measured value V3, and the device counter value C4 to the terminal device 500. In this case as well, in T122A, the reader 100 transmits data including the measured values measured by the remaining sensor tags 10 within the overlapping range 102a to the terminal device 500. The data corresponding to the remaining sensor tags 10 includes the same device counter value C4.
[0088] T120D is the same as T50B in Figure 3, except that the device counter value C6 of the reader 200 is assigned to it. In T122D, the reader 200 transmits data including the ID "tg3", the measured value V4, and the device counter value C6 to the terminal device 500. In this case as well, in T122D, the reader 200 transmits data including the measured values measured by the remaining sensor tags 10 within the reading range 202 to the terminal device 500. The data corresponding to the remaining sensor tags 10 includes the same device counter value C6.
[0089] In T120B, the reader 300 demodulates the response waves from the first duplicate tag 10b and the second duplicate tag 10c. The reader 300 obtains a signal from the response wave of the first duplicate tag 10b that includes the ID "tg2", the measured value V3, and the tag counter value "1" (S132). The reader 300 also obtains a signal from the response wave of the second duplicate tag 10c that includes the ID "tg3", the measured value V4, and the tag counter value "0" (S132). For the first duplicate tag 10b, the reader 300 generates data that includes the ID "tg2", the measured value V3, the current first device counter value C4, and the current second device counter value C5. Furthermore, for the second duplicate tag 10c, the reader 300 generates data that includes the ID "tg3", the measured value V4, the current first device counter value C4, and the current second device counter value C5. Here, the first device counter value C4 is the same as the device counter value C4 assigned by the reader 100 in T120A. On the other hand, the second device counter value C5 is different from the device counter value C6 assigned by the reader 200 in T120D.
[0090] In T122B, the reader 300 transmits the data generated in T120B to the terminal device 500. In this case, the reader 300 also transmits to the terminal device 500 the data including the measured values from the remaining sensor tags 10, excluding the two duplicate tags 10b and 10c, among all the sensor tags 10 included in the reading range 302 in T122B. The data corresponding to the remaining sensor tags 10 also includes the same combination, namely the first device counter value C4 and the second device counter value C5.
[0091] Furthermore, the reader 300 determines that the tag counter value attached to the response wave received from the second duplicate tag 10c in T116C is "0" (YES in S144). In T124B, the reader 300 resets the second device counter 142c (S146). Also, T124D is the same as T24B in Figure 4. As a result, the second device counter 142c of the reader 300 and the device counter 142 of the reader 200 are synchronized.
[0092] Furthermore, terminal device 500 receives data including the device counter value C4 from reader device 100 at T122A, and data including the device counter value C6 from reader device 200 at T122D. In addition, terminal device 500 receives data including two device counter values C4 and C5 from reader device 300 at T122B. As described above, the device counter value C6 of reader device 200 is different from the second device counter value C5 from reader device 300. Also, the difference between the two device counter values in the data from reader device 300 is C4-C5. The difference between the device counter value C4 of reader device 100 and the device counter value C6 of reader device 200 is C4-C6. That is, the difference C4-C5 is different from the difference C4-C6. Therefore, in T130, terminal device 500 determines that although the device counters are synchronized between reader 100 and reader 300, the device counters are not yet synchronized between reader 200 and reader 300. As a result, terminal device 500 does not analyze the data sets T122A to T122D.
[0093] Figure 9 is a continuation of Figure 8. T210A to T210D are the same as T110A to T110D in Figure 8. T212B, T214B, T216A, and T216B are the same as T112A, T114A, T116A, and T116B, except that the measured value V5 and tag counter value "2" obtained in the first duplicate tag 10b are used. Also, T212C, T214C, T216C, and T216D are the same as T112C, T114C, T116C, and T116D, except that the measured value V6 and tag counter value "1" obtained in the second duplicate tag 10c are used.
[0094] T220A and T222A are the same as T120A and T122A, except that they utilize the measured value V5 and the device counter value C7. T220D is the same as T120D and T122D, except that it utilizes the measured value V6 and the device counter value C8. T220B and T222B are the same as T220B and T222B, except that they utilize the measured values V5, V6, the first device counter value C7, and the second device counter value C8.
[0095] In the case shown in Figure 9, the device counter value C7 of reader 100 is the same as the first device counter value C7 of reader 300, and the device counter value C8 of reader 200 is the same as the second device counter value C8 of reader 300. Also, the difference between the two device counter values in the data from reader 300 is C7-C8. The difference between the device counter value C7 of reader 100 and the device counter value C8 of reader 200 is C7-C8. That is, the difference C7-C8 is the same as the difference C7-C8. Therefore, in T230, terminal device 500 determines that the device counters are synchronized both between reader 100 and reader 300, and between reader 200 and reader 300. The terminal device 500 synchronizes all measurement values acquired from the reading devices 100, 200, and 300, i.e., all measurement values corresponding to all sensor tags 10 installed on the surface of object 4, using the synchronized device counter values C7, C8, and the difference C7-C8. This allows for accurate analysis of all measurement values.
[0096] (Correspondence) Reader 100 and Reader 200 are examples of the "first reader" and "third reader," respectively. Reader 300 is an example of the "second reader." First device counter 142b and second device counter 142c are examples of the "counter for one device" and "counter for the other device," respectively. Reading range 102 and reading range 302 are examples of the "first range" and "second range," respectively. Reading range 202 is an example of the "third range." First overlapping range 302b and second overlapping range 302c are examples of the "first overlapping range" and "second overlapping range," respectively. First overlapping tag 10b and second overlapping tag 10c are examples of the "specific tag for one device" and "specific tag for the other device," respectively.
[0097] The above describes specific examples of the technology disclosed herein, but these are merely illustrative and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples described above. For example, the following modifications may be adopted.
[0098] (Modification 1) The signal for resetting the device counter 142 is not limited to a response wave containing the tag counter value "0", but may also be, for example, a pulse signal without any information attached. Even with such a pulse signal, it is possible to sporadically transmit a specific signal. However, a special program is required to transmit the pulse signal separately from the normal response wave with information attached. In contrast, in the embodiment that uses a response wave containing the tag counter value "0", no special program is required. The pulse signal in this modification is an example of a "specific response wave".
[0099] (Modification 2) The process in S12 of Figure 3 does not need to be executed. In this modification, the "selection section" can be omitted.
[0100] (Variation 3) The "predetermined number of times" is not limited to "0," but may be any other value between the minimum and maximum values, such as "10." Also, the tag counter 32 is not limited to a counter that counts the number of transmissions, but may be a timer that counts time, for example.
[0101] (Modification 4) The information reading system 2 does not need to be equipped with a terminal device 500. In this modification, the "analysis device" can be omitted.
[0102] The technologies disclosed herein are not limited to two readers, as in the first and second embodiments, or three readers, as in the third embodiment, but can also be applied to information reading systems including, for example, four or more readers.
[0103] The technical elements described herein or in the drawings demonstrate technical usefulness individually or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technologies illustrated herein or in the drawings achieve multiple objectives simultaneously, and achieving even one of these objectives constitutes technical usefulness in itself. [Explanation of Symbols]
[0104] 2: Information Reading System 4: Target 10: Sensor Tag 10a: Duplicate tags 10b: First duplicate tag 10c: Second duplicate tag 12: Antenna 14: Demodulation Unit 16: Modulation section 30: Assignment section 32: Tag Counter 40: Sensor 100: Reader 102: Reading range 102a: Overlapping range 112: Antenna 114: External I / F 130: Processing Unit 134: Demodulation Unit 134a: Demodulation section 134b: Demodulation section 134c: Demodulation section 136: Counter assignment section 140: Reset section 140b: First reset section 140c: Second reset section 142: Device Counter 142a: Device counter 142b: First device counter 142c: Second device counter 200: Reader 202: Reading range 300: Reader 302: Reading range 302b: First overlapping range 302c: Second overlapping range 500: Terminal device 510: Analysis Program C1~C8: Device counter values V1~V6: Measured values
Claims
1. An information reading system comprising a first reading device, a second reading device, and a plurality of tags, Each of the first reading device and the second reading device is: Device counter and A radio wave is repeatedly transmitted to read information from each of the aforementioned multiple tags, and an antenna capable of receiving a response wave to the radio wave from each of the aforementioned multiple tags is provided. A reset unit for resetting the device counter, Equipped with, Each of the aforementioned multiple tags is: An antenna capable of receiving the aforementioned radio waves and transmitting the aforementioned response waves, A unit that applies the aforementioned information to the response wave, Equipped with, The aforementioned plurality of tags include a plurality of sensor tags configured to be able to assign measured values output from the sensor to the response wave as information, and a specific tag. The aforementioned specific tag is installed within a first overlapping range where the first range readable by the first reader and the second range readable by the second reader overlap. The aforementioned specific tag is configured to transmit a specific response wave sporadically while the aforementioned response wave is being repeatedly transmitted. Both the reset unit of the first reader and the reset unit of the second reader reset the device counter when they receive the specific response wave from the specific tag. Information reading system.
2. Both the antenna of the first reader and the antenna of the second reader transmit search radio waves for searching for tags within the first overlapping range. Either the first reading device or the second reading device further, The information reading system according to claim 1, further comprising a selection unit that, when two or more tags are found within the first overlapping range, selects from among the two or more tags the tag with the highest received intensity of the response wave to the search radio wave and the highest received frequency of the response wave to the search radio wave as the specific tag.
3. The information reading system according to claim 2, wherein, after the first tag among the two or more tags has been selected as the specific tag, an abnormality occurs in the first tag, the selection unit selects the second tag among the two or more tags as the specific tag in place of the first tag.
4. The information reading system further includes a third reading device having the same configuration as the first reading device. The second reading device comprises two of the device counters, The aforementioned plurality of tags include two of the aforementioned specific tags, One of the two specified tags is located within the first overlapping area. The other of the two specific tags is installed within the second overlapping range where the second range readable by the second reader and the third range readable by the third reader overlap. The reset unit of the first reader device resets the device counter of the first reader device when it receives a specific response wave from one of the specific tags. The reset unit of the second reader device, when it receives the specific response wave from one of the specific tags, resets one of the two device counters but does not reset the other of the two device counters. The reset unit of the second reader device, when it receives the specific response wave from the other specific tag, resets the counter of the other device, but does not reset the counter of the first device. The information reading system according to claim 1, wherein the reset unit of the third reading device resets the device counter of the third reading device when it receives the specific response wave from the other specific tag.
5. The specified tag includes a tag counter that counts the number of times the response wave has been transmitted. The aforementioned specific tag is configured to be able to assign the counter value output from the tag counter to the response wave as the information, The information reading system according to any one of claims 1 to 4, wherein the specific response wave includes a value indicating a predetermined number of times as the counter value.
6. The information reading system according to any one of claims 1 to 4, wherein the specified tag is a sensor tag.
7. The aforementioned information reading system further includes an analysis device, Both the first reading device and the second reading device further, The device includes a transmission unit that adds the counter value output from the device counter to the measured value included in the response wave received from the plurality of tags and transmits it to the analysis device. The information reading system according to any one of claims 1 to 4, wherein the analysis device analyzes a plurality of measured values measured by the plurality of sensor tags based on the counter value assigned to the measured value received from either the first reading device or the second reading device.
8. A specific reading device, Device counter and An antenna that repeatedly transmits radio waves to read information from multiple tags and receives response waves to those radio waves from each of the multiple tags, A reset unit for resetting the device counter, Equipped with, The aforementioned plurality of tags include a plurality of sensor tags configured to be able to assign measured values output from the sensor to the response wave as information, and a specific tag. The aforementioned specific tag is installed within an overlapping range where the range readable by the aforementioned specific reader overlaps with the range readable by another reader different from the aforementioned specific reader. The aforementioned specific tag is configured to transmit a specific response wave sporadically while the aforementioned response wave is being repeatedly transmitted. The reset unit resets the device counter when it receives the specific response wave from the specific tag. A specific reading device.