Ultra-high frequency rfid temperature sensing system and temperature feedback method

Abstract

The application relates to an ultrahigh-frequency RFID temperature sensing system and a temperature returning method in the technical field of sensors. The method is applied to temperature returning of the GJB ultrahigh-frequency RFID temperature sensing system. The temperature returning method does not need to customize a new reader-writer instruction, only needs to point to a preset specific address of a starting address of a pointer in a classification command frame to start the ultrahigh-frequency RFID tag to perform temperature measurement once, saves the data to the specific address in a storage area after the temperature measurement is completed, and returns the temperature data to the reader-writer together with UAC coded data when the ultrahigh-frequency RFID tag receives the ACK command after the high-frequency RFID reader-writer sends the Ack command. The method has the advantages of simple realization, protocol compatibility, and the compatibility of the ultrahigh-frequency RFID temperature tag with most reader-writers on the market can be improved.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of sensors, in particular to an ultra-high frequency RFID temperature sensing system and a temperature returning method. BACKGROUND

[0002] With the wide application of RFID (Radio Frequency Identification) technology in the field of Internet of Things, more attention has been paid to low-voltage and low-power temperature sensor technology integrated in a tag chip. These applications include temperature monitoring in cold chain logistics, warehouse environment temperature monitoring, human body temperature measurement, temperature monitoring of important equipment in the power industry, etc. The traditional passive temperature sensor temperature returning method needs to customize a new temperature returning instruction to obtain the temperature measurement result, which will lead to the communication protocol of the tag chip not meeting the standard regulation (GJB7377.1), and since the tag chip needs to customize a new temperature measurement instruction, the tag chip will not be compatible with the read-write device on the market. SUMMARY

[0003] Therefore, it is necessary to provide an ultra-high frequency RFID temperature sensing system and a temperature returning method in view of the above technical problems.

[0004] A temperature returning method of an ultra-high frequency RFID temperature sensing system, the method is applied to a temperature measurement system composed of an ultra-high frequency RFID temperature tag and an ultra-high frequency RFID read-write device designed according to the GJB7377.1 standard, and the method comprises the following steps of:

[0005] The ultra-high frequency RFID read-write device sends a SortTemp command to the ultra-high frequency RFID temperature tag, and the SortTemp command is obtained by pointing the starting address of a pointer in a SORT command to a preset specific address.

[0006] After receiving the SortTemp command, the ultra-high frequency RFID temperature tag starts temperature measurement, and after the temperature measurement is completed, the temperature data is saved to the preset specific address in a storage area.

[0007] After receiving the ACK command sent by the ultra-high frequency RFID read-write device, the ultra-high frequency RFID temperature tag returns the temperature data to the ultra-high frequency RFID read-write device together with UAC encoded data.

[0008] In one embodiment, the ultra-high frequency RFID read-write device sends a SortTemp command to the ultra-high frequency RFID temperature tag, and the SortTemp command comprises the following steps of:

[0009] The starting address of the pointer in the Sort command is directed to 12h of the UHF RFID temperature tag information area, obtaining the SortTemp command.

[0010] The UHF RFID reader sends the SortTemp command to the UHF RFID temperature tag.

[0011] A UHF RFID temperature sensing system, comprising a UHF RFID temperature tag and a UHF RFID reader.

[0012] The UHF RFID reader and the UHF RFID temperature tag communicate through RFID radio frequency, and the temperature return method of any of the above UHF RFID temperature sensing systems is used to start the UHF RFID temperature tag to measure temperature and return temperature data to the UHF RFID reader.

[0013] The above UHF RFID temperature sensing system and temperature return method are applied to the temperature return of the GJB UHF RFID temperature sensing system. The temperature return method does not need to customize a new reader command. Only the starting address of the pointer in the classification command frame is directed to a preset specific address to start the UHF RFID tag to measure temperature once. After the temperature measurement is completed, the data is saved to the specific address in the storage area. When the high-frequency RFID reader sends the Ack command, the UHF RFID tag returns the temperature data together with the UAC encoded data to the reader when receiving the ACK command. The method has the advantages of simple implementation, protocol compatibility, and can improve the compatibility of the UHF RFID temperature tag with most readers on the market. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 The flowchart of the temperature return method of the UHF RFID temperature sensing system in one embodiment;

[0015] Figure 2 The link timing sequence of the communication between the UHF RFID temperature tag and the UHF RFID reader in another embodiment;

[0016] Figure 3 The internal structure diagram of the UHF RFID temperature tag in one embodiment. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical scheme and advantages of the present application clearer, the present application will be further described in detail below in combination with the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and do not limit the present application.

[0018] In one embodiment, asFigure 1 As shown, a temperature returning method of an ultra-high frequency RFID temperature sensing system is provided, the method is applied to a temperature measuring system composed of an ultra-high frequency RFID temperature tag and an ultra-high frequency RFID reader designed according to the GJB7377.1 standard, and the method comprises the following steps:

[0019] Step 100: an ultra-high frequency RFID reader sends a SortTemp command to an ultra-high frequency RFID temperature tag; the SortTemp command is obtained by pointing the start address of a pointer in a Sort command to a preset specific address.

[0020] Specifically, the format of the SortTemp command is completely consistent with that of the Sort command, so as to ensure the compatibility of the protocol; the SortTemp command is obtained by pointing the start address of a pointer in the Sort command to a preset specific address, and the SortTemp command is used to classify the ultra-high frequency RFID temperature tag according to the criterion set in the command and start a temperature measurement.

[0021] Among them, the Sort command classifies the tags according to a specific criterion, the classification command can change the matching flag of the tag, and the frame format of the Sort command is shown in Table 1.

[0022] Table 1 Frame format of Sort command

[0023]

[0024] The definition of each data field in the frame format of the Sort command is as follows:

[0025] a) Command code: 10101010 b , the code of the classification command.

[0026] b) Storage area: specifies the logical storage area where the matching data is located, and the meanings of the four values are as follows:

[0027] 1) 00 b : use the data in the tag information area for matching.

[0028] 2) 01 b : use the data in the encoding area for matching.

[0029] 3) 10 b : security area. If the storage area data field is 10 b , the tag does not respond to the classification command.

[0030] 4) 11 b : use the data in the user area for matching. The tag without a user area receives the storage area data field as 11 bIf the length data field is not 0, the tag does not match. Tags requiring security authentication do not respond to the store area data field being 11 b of the sort command.

[0031] If the logical store is locked as read-only, the tag does not respond to the sort command.

[0032] For tags supporting security authentication, if the read password is not 0, the tag does not respond to the store area data field being 00 b or 11 b of the sort command.

[0033] c) Rule: The rule that indicates the tag to set the match flag, four values are as follows:

[0034] 1) 00 b : The matching tag sets the match flag to 1 b , and the non-matching tag sets the match flag to

[0035] 0 b .

[0036] 2) 01 b : The matching tag keeps the match flag unchanged, and the non-matching tag sets the match flag to 0 b .

[0037] 3) 10 b : The matching tag sets the match flag to 1 b , and the non-matching tag keeps the match flag unchanged.

[0038] 4) 11 b : The matching tag sets the match flag to 0 b , and the non-matching tag sets the match flag to 1 b .

[0039] d) Pointer: The bit address of the starting matching logical store. If the pointer exceeds the access of the logical store, the tag does not match.

[0040] e) Length: Indicates the length of bits that need to be matched. If the length is 0 and the store area data field is not 10 b , the tag matches. If the matching length exceeds the range of the logical store, the tag does not match.

[0041] f) Mask: The data that needs to be matched, if the length data field is odd, 0 is added to the lowest bit of the mask b . The tag ignores the lowest bit of the mask when receiving the sort command with the matching length being odd.

[0042] g) Check: CRC-16 is calculated including command code, memory area, rule, pointer, length and mask data field. If the check included in the command received by the tag is wrong, the tag does not respond to the command. After the tag receives the SortTemp command, the matching flag is changed according to the rule, and no response data packet is sent to the reader.

[0043] Step 102: After the ultra-high frequency RFID temperature tag receives the SortTemp command, it starts a temperature measurement, and after the temperature measurement is completed, the temperature data is saved to a preset specific address in the memory area.

[0044] Step 104: When the ultra-high frequency RFID temperature tag receives the ACK command sent by the ultra-high frequency RFID reader, the ultra-high frequency RFID temperature tag returns the temperature data together with the UAC encoded data to the ultra-high frequency RFID reader.

[0045] Specifically, the encoding acquisition command (ACK command) is used to acquire the data of the encoding area, and the frame format of the ACK command is shown in Table 2.

[0046] Table 2 Frame format of ACK command

[0047] Data field Command code Handle Length 2 bits 16 bits Description 01 b ]] handle

[0048] The definitions of the data in the frame format of the ACK command are as follows:

[0049] a) Command code: 01 b , the code of the encoding acquisition command.

[0050] b) Handle: 11-bit random number sent by the ultra-high frequency RFID temperature tag during the inventory process and CRC-5, or 11-bit random number sent after receiving the handle update command and CRC-5.

[0051] After the ultra-high frequency RFID temperature tag receives the encoding acquisition command (ACK command), it sends a response data packet to the ultra-high frequency RFID reader, and the format of the response data packet is shown in Table 3.

[0052] Table 3 Response data packet format of ACK command

[0053]

[0054] The definitions of the data fields in the response data packet of the ACK command are as follows:

[0055] a) Security mode: whether security authentication and secure communication are required, and the meanings of the four values are as follows:

[0056] 1) 00 b : indicates that the tag does not support security authentication and secure communication.

[0057] 2)01 b : indicates that the tag supports security authentication and secure communication, but does not need to perform security authentication and secure communication.

[0058] 3)10 b : indicates that the tag supports security authentication and secure communication, but only needs to perform security authentication, and does not need to perform secure communication.

[0059] 4)11 b : indicates that the tag supports security authentication and secure communication, and needs to perform security authentication and secure communication.

[0060] b) encoding area: the data of the encoding area, including the encoding length, the encoding header and the encoding.

[0061] c) check: CRC-16 calculation contains security module and encoding area data field.

[0062] UAC encoding data is the response data packet of the ACK command.

[0063] The link timing of the communication between the ultra-high frequency RFID temperature tag and the ultra-high frequency RFID reader is shown in Figure 2 . Figure 2 T2 is the time for the temperature sensor to collect temperature once. The Query command is a start query command.

[0064] In the temperature return method of the above-mentioned ultra-high frequency RFID temperature sensing system, the method is applied to the temperature return of the GJB ultra-high frequency RFID temperature sensing system. The temperature return method does not need to customize a new reader instruction. Only the starting address of the pointer in the classification command frame is pointed to a preset specific address to start the ultra-high frequency RFID tag to measure temperature once. After the temperature measurement is completed, the data is saved to the specific address in the storage area. When the high-frequency RFID reader sends the Ack command, the temperature data is returned to the reader together with the UAC encoding data when the ultra-high frequency RFID tag receives the ACK command. The method has the advantages of simple implementation, protocol compatibility, and can improve the compatibility of the ultra-high frequency RFID temperature tag with most readers on the market.

[0065] In one embodiment, step 100 includes: pointing the starting address of the pointer in the Sort command to 12h of the ultra-high frequency RFID temperature tag information area to obtain the SortTemp command; and the ultra-high frequency RFID reader sends the SortTemp command to the ultra-high frequency RFID temperature tag.

[0066] Specifically, the pointer in the Sort command frame is pointed to 12h of the tag information area, and then a temperature measurement is started. This is the only difference between the SortTemp command and the Sort command.

[0067] It should be understood that although Figure 1 The steps in the flowcharts are shown in sequence according to the arrows, but the steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified herein, the execution of the steps is not strictly limited in sequence, and the steps can be executed in other orders. Moreover, Figure 1 At least part of the steps in the flowcharts can include multiple sub-steps or multiple stages, which are not necessarily executed at the same time, but can be executed at different times, and the execution order of the sub-steps or stages is not necessarily sequential, but can be alternately executed with other steps or sub-steps or stages of other steps.

[0068] In one embodiment, a UHF RFID temperature sensing system includes a UHF RFID temperature tag and a UHF RFID reader. The data communication protocol between the UHF RFID temperature tag and the UHF RFID reader adopts the protocol in GJB7377.1.

[0069] The UHF RFID reader and the UHF RFID temperature tag communicate through RFID radio frequency, and the UHF RFID temperature tag is started to measure temperature and return temperature data to the UHF RFID reader by using the temperature return method of any of the UHF RFID temperature sensing systems.

[0070] Specifically, as shown in Figure 3 The UHF RFID temperature tag mainly consists of an antenna, a radio frequency front end, an analog front end, a digital baseband, and an MTP memory. The radio frequency front end includes a demodulator, a modulator, a rectifier, an ESD protection device, and a voltage limiting circuit. The analog front end includes a temperature sensor, a bandgap reference, a clock, an LDO, and a POR circuit.

[0071] Working principle of the UHF RFID temperature tag: When the antenna end receives a radio frequency signal, the rectifier converts the radio frequency energy into a direct current voltage stored in the energy storage capacitor C1, which provides energy for the subsequent chip operation. The size of the energy storage capacitor determines the standby time of the chip.

[0072] C = I*T / V, wherein I is standby current (including leakage current), V is the difference between the rectifier output voltage and the minimum voltage for the chip to operate normally (the minimum voltage is 1V here), assuming that the rectifier voltage limit is 4V, then V = 4V-1V = 3V, E = Q*T = C*V*T2, wherein E is the energy storage energy, Q is the charge amount, and T2 is the cumulative temperature measurement and MTP time. To meet the temperature measurement for seven days and measure the temperature once every hour, the total number of temperature measurements required is 168. The energy required for one temperature measurement is 1nJ, the energy required for writing temperature data to MTP is 9nJ, the time required for one temperature measurement is 3ms, and the time required for writing MTP is 3ms. The total energy required for 168 temperature measurements is 1680nJ. Thus, C = 93.3uF. This calculation process does not take into account the power consumption of the chip leakage, and the value of the energy storage capacitor can be appropriately increased to ensure the standby time.

[0073] Any combination of the technical features in the above embodiments can be made. In order to make the description simple, all possible combinations of the technical features in the above embodiments are not described, but as long as the combination of the technical features does not exist, it should be considered as the scope of the description.

[0074] The above embodiments only express several implementation manners of the present application, and the description is more specific and detailed, but it should not be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, some modifications and improvements can be made, which are all within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A temperature backhaul method for an ultra-high frequency (UHF) radio frequency identification (RFID) temperature sensing system, the method comprising: The method is applied to a temperature measuring system composed of an ultra-high frequency RFID temperature tag and an ultra-high frequency RFID reader designed according to the GJB7377.1 standard, and the method comprises the following steps: The ultra-high frequency RFID reader sends a SortTemp command to the ultra-high frequency RFID temperature tag; the SortTemp command is obtained by pointing the starting address of a pointer in a SORT command to a preset specific address; specifically, the starting address of the pointer in the Sort command is pointed to 12h of the information area of the ultra-high frequency RFID temperature tag to obtain the SortTemp command; the ultra-high frequency RFID reader sends the SortTemp command to the ultra-high frequency RFID temperature tag; After receiving the SortTemp command, the ultra-high frequency RFID temperature tag starts a temperature measurement, and after the temperature measurement is completed, the temperature data is saved to the preset specific address in the storage area; After receiving the ACK command sent by the ultra-high frequency RFID reader, the ultra-high frequency RFID temperature tag returns the temperature data to the ultra-high frequency RFID reader together with UAC encoded data.

2. An ultra-high frequency (UHF) RFID temperature sensing system, comprising: The system comprises an ultra-high frequency RFID temperature tag and an ultra-high frequency RFID reader; The ultra-high frequency RFID reader communicates with the ultra-high frequency RFID temperature tag through an RFID radio frequency mode, and the temperature return method of the ultra-high frequency RFID temperature sensing system according to claim 1 is used to start the ultra-high frequency RFID temperature tag to measure the temperature and return the temperature data to the ultra-high frequency RFID reader.

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