CN116112888A - UHF RFID temperature sensing system and temperature return method - Google Patents

Abstract

The application relates to an ultra-high frequency RFID temperature sensing system and a temperature return method in the field of sensor technology. This method is applied to the temperature return of the GJB ultra-high frequency RFID temperature sensing system. This temperature return method does not need to customize a new reader command, but only needs to point the starting address of the pointer in the classification command frame to the preset specific The address starts the UHF RFID tag for a temperature measurement, and saves the data to a specific address in the storage area after the temperature measurement is completed; when the HF RFID reader sends the Ack command, when the UHF RFID tag receives the ACK command Return the temperature data to the reader along with the UAC encoded data. The method has the advantages of simple implementation and protocol compatibility, and can improve the compatibility of UHF RFID temperature tags with most readers on the market.

Description

UHF RFID temperature sensing system and temperature return method

technical field

The present application relates to the technical field of sensors, in particular to an ultra-high frequency RFID temperature sensing system and a temperature return method.

Background technique

With the widespread application of RFID (Radio Frequency Identification) technology in the field of the Internet of Things, the low-voltage, low-power temperature sensor technology integrated in the tag chip has received more attention. These applications include temperature monitoring in the cold chain logistics process, storage environment temperature monitoring, human body temperature measurement, temperature monitoring of important equipment in the power industry, etc. The traditional passive temperature sensor temperature return method needs to customize a new temperature return command to obtain the temperature measurement result, which will cause the communication protocol with the tag chip to not comply with the standard regulations (GJB7377.1), because the tag chip needs to be customized A new temperature measurement instruction will result in incompatibility with the readers on the market.

Contents of the invention

Based on this, it is necessary to provide an ultra-high frequency RFID temperature sensing system and a temperature return method for the above technical problems.

A temperature return method for 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 label designed according to the GJB7377.1 standard and an ultra-high frequency RFID reader-writer. The methods described include:

The UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag; the SortTemp command is obtained by pointing the start address of the pointer in the SORT command to a preset specific address.

The UHF RFID temperature tag starts a temperature measurement after receiving the SortTemp command, and saves the temperature data to the preset specific address in the storage area after the temperature measurement is completed.

When the UHF RFID temperature tag receives the ACK command sent by the UHF RFID reader, the UHF RFID temperature tag returns the temperature data together with the UAC coded data to the UHF Frequency RFID reader.

In one of the embodiments, the UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag, including:

Point the starting address of the pointer in the Sort command to 12h of the UHF RFID temperature label information area to obtain the SortTemp command.

The UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag.

An ultra-high frequency RFID temperature sensing system includes an ultra-high frequency RFID temperature label and an ultra-high frequency RFID reader.

The UHF RFID reader-writer communicates with the UHF RFID temperature tag through RFID radio frequency mode, and adopts the temperature return method of any one of the UHF RFID temperature sensing systems to start the UHF RFID temperature tag. The tag measures the temperature and sends the temperature data back to the UHF RFID reader.

The above-mentioned UHF RFID temperature sensing system and temperature return method, this method is 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 It is necessary to point the starting address of the pointer in the classification command frame to the preset specific address to start the UHF RFID tag for a temperature measurement. After the temperature measurement is completed, the data will be saved to a specific address in the storage area; when the high frequency RFID reader sends After the Ack command, when the UHF RFID tag receives the ACK command, the temperature data will be returned to the reader along with the UAC coded data. Compatibility with most readers on the market.

Description of drawings

Fig. 1 is the schematic flow sheet of the temperature return method of UHF RFID temperature sensing system in an embodiment;

Fig. 2 is the link sequence of communication between UHF RFID temperature tag and UHF RFID reader-writer in another embodiment;

Fig. 3 is an internal structure diagram of a UHF RFID temperature tag in one embodiment.

Detailed ways

In order to make the purpose, technical solution and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present application, and are not intended to limit the present application.

In one embodiment, as shown in Figure 1, a temperature return method for an ultra-high frequency RFID temperature sensing system is provided, which is applied to an ultra-high frequency RFID temperature label and an ultra-high temperature sensor designed according to the GJB7377.1 standard. In a temperature measuring system composed of a frequency RFID reader, the method includes:

Step 100: the UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag; the SortTemp command is obtained by pointing the starting address of the pointer in the Sort command to a preset specific address.

Specifically, the format of the classification temperature return command (SortTemp command) is completely consistent with the classification command (Sort command), which ensures the compatibility of the protocol; the initial address of the pointer in the Sort command is pointed to the preset specific address to obtain the SortTemp command, and the SortTemp command It is used to classify UHF RFID temperature tags according to the criteria set in this command and start a temperature measurement.

Among them, the Sort command classifies the labels according to specific criteria, and the classification command can change the matching flag of the label. The frame format of the Sort command is shown in Table 1.

Table 1 The frame format of the Sort command

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

a) Command code: 10101010 _b , the code of the classification command.

b) Storage area: Specify the logical storage area where the matching data is located. The meanings of the four values are as follows:

1)00 _b : Use the data in the label information area for matching.

2)01 _b : Use the data in the coded region for matching.

3) 10 _b : safe zone. If the memory area data field is _10b , the tag does not respond to this sort command.

4)11 _b : Use the data in the user area for matching. When a label without user area receives a classification command whose storage area data field is 11 _b , if the length data field is not 0, the label does not match. Tags that require security authentication do not respond to classification commands whose data field is 11 _b in the storage area.

If the logical memory area is locked unreadable, the tag does not respond to the sort command.

For tags that support security authentication, if the read password is not 0, the tag will not respond to the classification command whose data field in the storage area is 00 _b or 11 _b .

c) Rules: Indicates the rules for setting matching flags on tags. The meanings of the four values are explained as follows:

1) 00 _b : Matching tags set the match flag to 1 _b , non-matching tags set the match flag to

_0b .

2) 01 _b : The matching flag of the matched tag remains unchanged, and the matching flag of the unmatched tag is set to 0 _b .

3) 10 _b : The matched tag sets the matching flag to 1 _b , and the matching flag of the unmatched tag remains unchanged.

4) 11 _b : Matching tags set the match flag to 0 _b , non-matching tags set the match flag to 1 _b .

d) Pointer: Points to the bit address of the logical storage area to start matching. If the pointer is accessed beyond that logical memory area, the tag does not match.

e) Length: Indicates the bit length to be matched. If the length is 0 and the bucket data field is not _10b , the tag matches. If the match length exceeds the bounds of the logical memory area, the tag does not match.

f) Mask: the data to be matched, if the length data field is an odd number, add 0 _b to the lowest bit of the mask. The tag ignores the least significant bit of the mask when it receives a classification command that matches an odd length.

g) Checksum: CRC-16 calculation includes command code, storage area, rule, pointer, length and mask data fields. If the checksum contained in the command received by the tag is wrong, the tag will not respond to the command. After the tag receives the classification command, it changes the matching flag according to the rules, and does not send a response packet to the reader.

Step 102: The UHF RFID temperature tag starts a temperature measurement after receiving the SortTemp command, and saves the temperature data to a preset specific address in the storage area after the temperature measurement is completed.

Step 104: After the UHF RFID temperature tag receives the ACK command sent by the UHF RFID reader-writer, the UHF RFID temperature tag returns the temperature data together with the UAC coded data to the UHF RFID reader-writer.

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

Table 2 Frame format of ACK command

data field command code the handle length 2 digits 16 bits describe <![CDATA[01_b]]> handle

The definition of data in the frame format of the ACK command is as follows:

a) Command code: 01 _b , encode the code to obtain the command.

b) Handle: the 11-digit random number and CRC-5 sent by the UHF RFID temperature tag during the inventory process, or the 11-digit random number and CRC-5 sent after receiving the handle update command.

After receiving the code acquisition command (ACK command), the UHF RFID temperature tag sends a response packet to the UHF RFID reader. The format of the response packet is shown in Table 3.

Table 3 Response packet format of ACK command

The definition of a data field in the response packet of the ACK command is:

a) Security mode: up to whether security authentication and security communication are required, the meanings of the four values are explained as follows:

1) 00 _b : Indicates that the tag does not support security authentication and security communication.

2) 01 _b : Indicates that the tag supports security authentication and secure communication, but does not require security authentication and secure communication.

3) 10 _b : Indicates that the tag supports security authentication and secure communication, but only security authentication is required, and secure communication is not required.

4) 11 _b : Indicates that the tag supports secure authentication and secure communication, and requires secure authentication and secure communication.

b) Coding area: the data in the coding area, including the code length, code header and code.

c) Checksum: CRC-16 calculation includes the data field of the security module and the coding area.

The UAC encoded data is the response packet of the ACK command.

The link sequence of the communication between the UHF RFID temperature tag and the UHF RFID reader is shown in Figure 2. _T2 in Figure 2 is the time for the temperature sensor to collect a temperature. Query command is to start query command.

In the temperature return method of the above-mentioned UHF RFID temperature sensing system, this method is applied to the temperature return of the GJB UHF RFID temperature sensing system. This temperature return method does not need to customize a new reader command, Just point the starting address of the pointer in the classification command frame to the preset specific address to start the UHF RFID tag to measure the temperature once, and save the data to the specific address in the storage area after the temperature measurement is completed; when the high frequency RFID reader After sending the Ack command, when the UHF RFID tag receives the ACK command, the temperature data will be returned to the reader along with the UAC encoded data. The advantage of this method is that it is simple to implement and compatible with the protocol. Compatibility with most readers and writers on the market.

In one of the embodiments, step 100 includes: pointing the starting address of the pointer in the Sort command to 12h of the UHF RFID temperature tag information area to obtain the SortTemp command; the UHF RFID reader-writer sends the SortTemp command to the UHF RFID temperature tags.

Specifically, point the pointer in the Sort command frame to 12h in the label information area, and start a temperature measurement. This is the only difference between the SortTemp command and the Sort command.

It should be understood that although the various steps in the flow chart of FIG. 1 are displayed sequentially according to the arrows, these steps are not necessarily executed sequentially in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least some of the steps in FIG. 1 may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but may be executed at different times. The execution of these sub-steps or stages The order is not necessarily performed sequentially, but may be performed alternately or alternately with at least a part of other steps or sub-steps or stages of other steps.

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

The UHF RFID reader-writer and the UHF RFID temperature tag communicate through the RFID radio frequency method, and use the temperature return method of any of the UHF RFID temperature sensing systems to start the UHF RFID temperature tag for temperature measurement, and Send the temperature data back to the UHF RFID reader.

Specifically, as shown in FIG. 3 . UHF RFID temperature tags are mainly composed of antenna, RF front-end, analog front-end, digital baseband and MTP memory. The RF front-end includes demodulator, modulator, rectifier, ESD protection device, voltage limiting circuit, and the analog front-end includes temperature sensor, Bandgap reference, clock, LDO, POR and other circuits.

The 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 DC voltage and stores it in the energy storage capacitor C1, which provides energy for the subsequent work of the chip. The size determines the standby time of the chip.

From the formula I=C*V/T, we get C=I*T/V, where I is the standby operating current (including leakage current), and V is the difference between the output voltage of the rectifier and the minimum voltage for normal operation of the chip (the minimum voltage here is is 1v), assuming that the rectifier limit voltage is 4v, then V=4v-1v=3v, E=Q*T=C*V*T ₂ , where E is the stored energy, Q is the amount of charge, and T ₂ is the cumulative measured Wen then writes the MTP time. It is necessary to meet the temperature measurement for seven days and measure the temperature every one hour, so the total number of temperature measurements required is 168 times. 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, then the total energy required for 168 temperature measurements is 1680nJ. From this, C=93.3uF can be obtained. This calculation process does not consider the power consumption of chip leakage, and the value of the energy storage capacitor can be appropriately increased to ensure the standby time.

The technical features of the above embodiments can be combined arbitrarily. To make the description concise, all possible combinations of the technical features in the above embodiments are not described. However, as long as there is no contradiction in the combination of these technical features, they should be It is considered to be within the range described in this specification.

The above-mentioned embodiments only represent several implementation modes of the present application, and the description thereof is relatively specific and detailed, but it should not be construed as limiting the scope of the patent for the invention. It should be noted that those skilled in the art can make several modifications and improvements without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the scope of protection of the patent application should be based on the appended claims.

Claims (3)

1. A temperature return method of an ultra-high frequency RFID temperature sensing system, characterized in that, the method is applied to a system composed of an ultra-high frequency RFID temperature tag designed according to the GJB7377.1 standard and an ultra-high frequency RFID reader-writer In the temperature measurement system, the method includes: The UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag; the SortTemp command is obtained by pointing the initial address of the pointer in the SORT command to a preset specific address; The UHF RFID temperature tag starts a temperature measurement after receiving the SortTemp command, and saves the temperature data to the preset specific address in the storage area after the temperature measurement is completed; When the UHF RFID temperature tag receives the ACK command sent by the UHF RFID reader, the UHF RFID temperature tag returns the temperature data together with the UAC coded data to the UHF Frequency RFID reader. 2. The method according to claim 1, wherein the UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag, comprising: The starting address of the pointer in the Sort command is pointed to 12h of the UHF RFID temperature tag information area to obtain the SortTemp command; The UHF RFID reader/writer sends a SortTemp command to the UHF RFID temperature tag. 3. A UHF RFID temperature sensing system, characterized in that the system includes a UHF RFID temperature tag and a UHF RFID reader/writer; The UHF RFID reader-writer communicates with the UHF RFID temperature tag through RFID radio frequency mode, adopting the temperature return method of the UHF RFID temperature sensing system described in any one of claims 1-2 Start the UHF RFID temperature tag to measure the temperature, and send the temperature data back to the UHF RFID reader.

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