JP7797946B2 - RFID system, allocation device, and allocation method - Google Patents

Description

The present invention relates to the assignment of variables in RFID systems.

RFID (Radio Frequency Identifier) tags communicate with reader/writers without contact, and store data received from the reader/writer in the RFID tag's non-volatile memory. The reader/writer also reads data stored in the RFID tag without contact. RFID systems using such reader/writers and RFID tags are widely used.

Patent Document 1 discloses technology for dumping memory contents as a memory dump and analyzing the memory dump. Patent Document 1 also discloses that when analyzing a memory dump, the contents of tables from the memory dump are analyzed, and the data is displayed in a way that is easy for people to understand, unnecessary parts are deleted, and necessary parts are highlighted.

Japanese Patent Application Publication No. 9-106362

Here, EEPROM (Electrically Erasable Programmable Read-Only Memory) (registered trademark), a non-volatile memory used in RFID tags, performs memory access in units of memory blocks, which are collections of multiple consecutive bytes. In other words, when accessing (retrieving or updating) a specific variable, it is necessary to access all memory blocks in which that variable is stored.

As a result, depending on how variables are allocated, variables that would fit in a single memory block may be allocated to multiple memory blocks, resulting in wasted memory access.

In addition, the EEPROM used in RFID tags has a limit on the number of writes (updates), which is around 100,000. Therefore, if multiple variables are assigned to one memory block, updating the other variables will consume writes, which can shorten the lifespan of the RFID tag.

One aspect of the present invention aims to reduce wasted memory accesses when assigning variables in RFID tags.

In order to solve the above problems, one aspect of the present invention provides an RFID system that uses an RFID tag that accesses memory on a memory block-by-memory block basis, which is an address unit of a predetermined block size. The system includes an acquisition unit that acquires multiple variables to be allocated to the memory of the RFID tag and the size or address range of each variable, and an allocation unit that allocates the variables to memory such that the number of memory blocks used by the variables is the number of memory blocks required to allocate the variables, which is determined from the size or address range of the variables.

In the above configuration, each variable is allocated to the required number of memory blocks, allowing each variable to be accessed with minimal memory access. This makes memory access efficient.

The allocation unit may allocate a different memory block for each variable.

In the above configuration, each variable is assigned to a different memory block, so a single memory block is not shared by multiple variables. This allows for a longer lifespan for RFID tags, which have a limited number of updates.

If allocating the second variable to the area following the area allocated to the first variable would result in the number of memory blocks used by the second variable being greater than the required number of memory blocks, the allocating unit may allocate the second variable to a different memory block rather than to the memory block allocated to the first variable.

In the above configuration, multiple variables can share a single memory block. This reduces the amount of non-volatile memory used in the RFID tag. Also, since the number of memory blocks used can be reduced, memory access becomes faster.

The RFID system may further include a warning unit that issues a warning if the number of memory blocks used by the variables assigned by the user is greater than the required number of memory blocks.

With the above configuration, a warning can be issued if the number of memory blocks used by variables allocated by user input is greater than the number of memory blocks required.

The acquisition unit may further acquire information about groups containing multiple variables, and the RFID system may further include a warning unit that issues a warning when variables belonging to different groups are assigned to a single memory block.

With the above configuration, a memory block can be assigned to each group of multiple variables that often have memory access at the same time. Therefore, even if multiple variables share a single memory block, multiple variables that have memory access at the same time will be included in the same group, achieving efficient memory access, a longer lifespan for RFID tags, and faster memory access.

The acquisition unit may further acquire the update frequency of the variables, and the RFID system may further include a warning unit that, when a single memory block contains at least two of the variables, compares the update frequency of one variable with the update frequency of another variable and issues a warning according to predetermined conditions.

In the above configuration, when multiple variables share a single memory block, the allowable combinations of variables can be limited depending on the update frequency of the variables assigned to that single memory block.

For example, if a variable that is updated frequently and a variable that does not need to be changed after being written once share a single memory block, it may be possible to adequately guarantee the lifespan of the RFID tag. However, if a variable that is updated frequently at one time and a variable that is updated frequently at another time share a single memory block, it may not be possible to guarantee the lifespan of the RFID tag. By taking the update frequency into consideration, such cases can be prevented, thereby achieving a longer lifespan for RFID tags.

The RFID system may further include a warning unit that issues a warning if the variable is allocated outside a predetermined memory area.

The above configuration allows you to limit the memory blocks to which variables are assigned. This prevents variables from being assigned to reserved areas where they should not be assigned, preventing improper operation of the RFID system.

To solve the above problem, an allocation device according to another aspect of the present invention allocates memory to an RFID tag that accesses memory on a memory block-by-memory block basis, which is an address unit of a predetermined block size. The allocation device includes an acquisition unit that acquires multiple variables to allocate to the memory of the RFID tag and the size or address range of each variable, and an allocation unit that allocates the variables to memory such that the number of memory blocks used by the variables is the number of memory blocks required to allocate the variables, which is determined from the size or address range of the variables.

To solve the above problem, an allocation method according to another aspect of the present invention includes an acquisition step of acquiring multiple variables to be allocated to the memory of an RFID tag and the size or address range of each variable, and an allocation step of allocating the variables to memory so that the number of memory blocks used by the variables is the number of memory blocks required to allocate the variables, as determined from the size or address range of the variables.

One aspect of the present invention improves the efficiency of memory access in RFID tags.

1 is a block diagram showing a configuration of a main part of an RFID system according to a first embodiment. This is a setting item for allocation information. This is the result of allocating the allocation information in FIG. 2 according to allocation rule 1 when the memory block is 4 bytes. This is the result of allocating the allocation information in FIG. 2 according to allocation rule 2 when the memory block is 4 bytes. This is the result of allocating the allocation information in FIG. 2 according to allocation rule 3 when the memory block is 4 bytes. This is the result of variable allocation in a case where a memory block of 4 bytes is allocated to multiple variables based on groups. This is a condition table that determines whether to issue a warning under certain conditions when multiple variables share a single memory block. This is a condition table that determines whether to issue a warning under different conditions when multiple variables share a single memory block.

[Embodiment 1]
Hereinafter, an embodiment according to one aspect of the present invention (hereinafter also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and description thereof will not be repeated.

§1 Application Example Fig. 1 is a block diagram showing the configuration of the main parts of an RFID system 1 according to embodiment 1. As shown in Fig. 1, the RFID system 1 includes a server (allocation device) 2, a reader/writer 3, and an RFID tag 4. In the RFID system 1, the server 2 accepts user operations, determines the allocation of memory to be written to the RFID tag 4, and updates the memory of the RFID tag 4 with the determined allocation via the reader/writer 3.

In the non-volatile memory used in RFID tags 4, memory access is performed in units of memory blocks, which are collections of multiple consecutive bytes. Therefore, if the memory allocation situation involves assigning variables across memory blocks, unnecessary memory access occurs. This means that the time required for memory access increases, making it inefficient.

In this embodiment, an RFID system is realized that has the function of preventing allocations that result in inefficient memory access.

§2 Configuration example (Configuration of RFID system 1)
The server 2 is operated by a user who assigns variables to the memory of the RFID tag 4, and handles everything from inputting variables to be assigned by the user to actually assigning the variables. If an abnormality occurs in an assigned variable, the server 2 issues a warning.

The reader/writer 3 acquires and/or updates data from the RFID tag 4 according to instructions from the server 2.

The RFID tag 4 stores data in non-volatile memory and outputs and/or updates the data by wirelessly communicating with a reader/writer. The non-volatile memory uses EEPROM.

(Configuration of Server 2)
The server 2 includes an acquisition unit 21, an allocation unit 23, and a warning unit 24. The server 2 is also connected to a display 51, a keyboard 52, and an indicator light 53.

The acquisition unit 21 acquires information regarding variable allocation from an external device and outputs it to the allocation information 22. The acquisition unit 21 may also input the variables to be allocated via user input via the keyboard 52 or the like and output it to the allocation information 22.

Figure 2 shows the setting items of the allocation information 22. As shown in Figure 2, the allocation information 22 contains the variable name, variable type, start address, end address, and variable size. In other words, the acquisition unit 21 acquires multiple variables to be allocated to the RFID tag's memory and the size or address range of each variable.

Of these, the start address, end address, and size of the variable are interrelated. Changing the size of the variable changes the end address taking the start address into account, and changing the end address changes the size of the variable taking the start address into account. Changing the start address changes the end address taking the size of the variable into account.

There is also a correlation between some variable types and the size of the variable. For example, "INT" represents a 16-bit integer and is 2 bytes, so the variable size is 2. "LONG" represents a 64-bit integer and is 8 bytes, so the variable size is 8. In contrast, "ASCII" represents a 1-byte code, with 1 byte representing 1 character, so the variable size essentially corresponds to the number of characters. Also, "BOOL" actually has a variable size of 1 bit, but is assigned a size of 1 byte from the perspective of memory access. "BCD" has a variable size that corresponds to the number of decimal digits.

The allocation unit 23 allocates variables to the non-volatile memory of the RFID tag in accordance with the allocation information 22. Furthermore, if the setting items described in the allocation information 22 do not conform to predetermined rules, the allocation unit 23 also has the function of appropriately correcting them in accordance with the predetermined allocation rules and allocating variables (automatic allocation). Details of the predetermined allocation rules will be provided later.

The warning unit 24 issues a warning via the indicator light 53 when a setting item described in the allocation information 22 is in a state where wasteful memory access occurs or when allocation exceeds a specified memory area. The medium for issuing the warning is not limited to an indicator light, and any medium or method may be used. For example, the warning may be displayed on the display 51.

In addition, after the allocation unit 23 allocates variables and modifies the allocation information 22, the acquisition unit 21 may accept user input and change the variable allocation as appropriate. Even in this case, the warning unit 24 remains operational and can issue a warning.

(Regarding non-volatile memory)
Here, we will explain the memory configuration of the nonvolatile memory of the RFID tag 4. In the RFID tag 4, the nonvolatile memory is divided into a number of memory blocks for management. The memory blocks are address units of a predetermined block size. The block size of the memory blocks varies depending on the RFID tag 4. For example, in this embodiment, the block size of the memory blocks is 4 bytes.

Memory access to the RFID tag 4 is performed on a memory block basis. In other words, even if access is made to only a portion of an address contained in a memory block, memory access is made to the entire memory block.

For example, let's consider the case where address 0x00 in the first memory block (addresses 0x00 to 0x03) is accessed. Address 0x00 is the target of access, so memory access is performed, and addresses 0x01 to 0x03 are included in the same memory block, so memory access is also performed. Memory access can be for data acquisition (reading) or data updating (writing).

In addition, the non-volatile memory used in RFID tags 4 has a limited number of updates, typically around 100,000 times. Therefore, the lifespan of the RFID tag is determined by the update frequency and number of updates.

§3 Example of operation (type of allocation rule)
The allocation rules in the allocation unit 23 are roughly divided into three types: allocation rule 1, which respects user input, allocation rule 2, which prioritizes the lifespan of RFID tags, and allocation rule 3, which prioritizes high-speed memory access to RFID tags.

(Regarding allocation rule 1)
In allocation rule 1, in order to respect user input, the allocation unit 23 does not automatically allocate variables, but only allocates variables to memory blocks in accordance with allocation information 22 obtained from user input.

Figure 3 shows the result of allocating the allocation information 22 in Figure 2 according to allocation rule 1 for a 4-byte memory block. Figure 3 is a table showing memory blocks in the rows and addresses in the memory blocks in the columns. The MSB (Most Significant Bit) is the most significant bit, and the LSB (Least Significant Bit) is the least significant bit.

As shown in Figure 3, variable A is 3 bytes in size and can be allocated with just one memory block, but is actually allocated from 0x02 to 0x04, spanning two memory blocks. Also, variable B is 8 bytes in size and can be allocated with just two memory blocks, but is actually allocated from 0x05 to 0x0C, spanning three memory blocks. Therefore, memory access to these memory blocks is inefficient.

In contrast, the variables 0x10, to which variable C is assigned, 0x12-0x13, to which variable D is assigned, and 0x14-0x17, to which variable E is assigned, are all contained in a single memory block. Therefore, memory access to these memory blocks is efficient.

As such, the number of allocated memory blocks and the number of memory blocks required to allocate a variable (minimum number of memory blocks required), calculated from the variable's size or address range, can be different values. In such cases, memory access to these variables will require not the minimum memory access, but rather memory access to the number of memory blocks required plus one, resulting in excessive memory access.

The required number of memory blocks is calculated using the following formula:
Required number of memory blocks = (variable size / block size)
Allocation rules 2 and 3, which will be explained below, differ from allocation rule 1 in that the number of memory blocks used by a variable is set to the number of required memory blocks.

(Regarding allocation rule 2)
Allocation rule 2 allocates a different memory block for each variable, i.e., only one variable is allocated to a single memory block.

Figure 4 shows the result of allocating allocation information 22 in Figure 2 according to allocation rule 2 when the memory block is 4 bytes. Variables A to E are allocated to memory blocks based on the required number of memory blocks. This allows each variable to be accessed with the minimum number of memory accesses, resulting in efficient memory access.

It can also be seen that the memory blocks containing variables A through E do not contain any other variables. Therefore, a single memory block is not shared by multiple variables. When a variable is updated, only the memory block containing the target variable is updated, which extends the lifespan of RFID tags 4, which have a limited number of updates.

Here, for areas of the memory block to be updated where no variables have been assigned, padding is performed by writing all bits of 0 or 1.

(Regarding allocation rule 3)
Allocation rule 3, when allocating an already allocated first variable and an unallocated second variable, packs multiple variables into a single memory block as closely as possible, while keeping the number of memory blocks used by the variables as the required number of memory blocks. In other words, if allocating the second variable to the area following the area allocated to the first variable would result in the number of memory blocks used by the second variable being greater than the required number of memory blocks, the second variable is not allocated to the memory block allocated to the first variable, but is allocated to a different memory block.

Figure 5 shows the result of allocating allocation information 22 in Figure 2 according to allocation rule 3 for a 4-byte memory block.

Specifically, the allocation unit 23 first allocates variable A to 0x00 to 0x02. Next, variable B is allocated, but the required number of memory blocks is two. If variable B is allocated to the area following variable A, variable B will use three memory blocks. Therefore, variable B is allocated to a different memory block, 0x04 to 0x0B. After variable B is allocated, the free size of the same memory block is zero, so variable C is allocated to a different memory block, 0x0C. Next, variable D is allocated, but the required number of memory blocks is two. Even if variable D is allocated to the area following variable C, variable D will only use two memory blocks. Therefore, variable D is allocated to 0x0D to 0x12, the area following variable C. Finally, variable E is allocated, but the required number of memory blocks is one. If variable E is allocated to the area following variable D, variable E will use two memory blocks. Therefore, variable E is assigned to a different memory block, 0x14 to 0x15.

As a result, variables A through E are allocated to memory blocks based on the required number of memory blocks. This allows each variable to be accessed with minimal memory access, resulting in efficient memory access.

Comparing Figures 4 and 5, the total number of memory blocks used is smaller in Figure 5 than in Figure 4. This is because the second variable is assigned to the area following the area assigned to the first variable, allowing multiple variables to share a single memory block. This reduces the amount of non-volatile memory used in the RFID tag. Furthermore, because the number of memory blocks used can be reduced, access to multiple variables can be consolidated, resulting in faster memory access.

Here, for areas of the memory block to be updated where no variables have been assigned, padding is performed by writing all bits of 0 or 1.

(Regarding the warning section)
After automatic allocation is performed by the allocation unit 23, the user may check whether the allocation is as intended based on various conditions and manually correct the allocation information 22. At this time, it is necessary to check whether the number of memory blocks used by each variable is the required number of memory blocks. For this purpose, the warning unit 24 checks the allocation information 22 and issues a warning to the user if an abnormality occurs.

The warning unit 24 issues a warning if the number of memory blocks used by the variable allocated by the user is greater than the number of memory blocks required. In other words, it determines whether the variable has been allocated across an excess of memory blocks. Therefore, by eliminating the warning from the warning unit 24, efficient memory access can be maintained even after the allocation information 22 has been manually modified by the user.

The warning unit 24 also issues a warning if a variable is allocated outside a predetermined memory area. In other words, the warning is issued based on whether the memory block to which the variable is allocated can be used, so the memory blocks to which variables can be allocated can be limited. This makes it possible to set reserved areas to which variables must not be allocated, and since variables will not be allocated to these reserved areas, it is possible to prevent unintended writing to memory blocks during operation of the RFID system.

§4 Variations (Block Size)
In the first embodiment, the block size is set to 4 bytes, but is not limited to this. For example, any integer such as 8 bytes may be used. The allocation results for a block size of 4 bytes shown in Figures 4 to 6 are different from the allocation results for a block size of 8 bytes, and the allocation changes depending on the block size.

(Another aspect of the RFID system 1)
In the first embodiment, the RFID system 1 includes the server 2, the reader/writer 3, and the RFID tag 4, but is not limited to this. For example, the server 2 may be replaced with a personal computer or a programmable logic controller (PLC).

Alternatively, there may be no server 2, and the reader/writer 3 may have web server functionality and be capable of performing variable assignment processing.

In the first embodiment, an RFID system 1 was described, but the present invention is not limited to an RFID system and may be any allocation device for RFID tags 4. The allocation device may be a variety of devices, such as a server, a personal computer, a PLC, or a reader/writer equipped with a web server.

(Group assignment)
A group of multiple variables that are targets of memory access at the same time may be included in the setting items of the allocation information 22. In other words, the acquisition unit 21 further acquires information on a group that includes multiple variables (information indicating the correspondence between variables and groups).

The allocation unit 23 performs automatic allocation for multiple variables belonging to one group, and then performs automatic allocation for multiple variables belonging to another group. In other words, automatic allocation is performed on a group-by-group basis. Here, different groups are prevented from sharing memory blocks. Also, since a single memory block will be shared by multiple variables, allocation rule 3 will be used.

In addition to the allocation unit 23, the warning unit 24 may also perform group-specific processing. The warning unit 24 issues a warning when variables belonging to different groups are assigned to a single memory block.

This makes it possible to allocate a memory block to each group of multiple variables that often have memory access at the same time. Furthermore, even if multiple variables share a single memory block, multiple variables that have memory access at the same time will be included in the same group, achieving efficient memory access, a longer lifespan for the RFID tag 4, and high-speed memory access.

For example, in Figure 2, assume that variables A and C are in group 1, variable B is in group 2, and variables D and E are in group 3. The resulting variable assignments in this case are shown in Figure 6.

To process allocation rule 3 for each group, variable A is first assigned to 0x00-0x02 for group 1. Next, variable C is assigned, but the required number of memory blocks is 1. If variable C is assigned to the area following variable A, variable C will use up one memory block. Therefore, variable C is assigned to 0x03, which is the same memory block. Next, variable B, which is in a different group, is assigned to another memory block, 0x04-0x0B. Furthermore, variable D, which is in a different group, is assigned to another memory block, 0x0C-0x11. Next, variable E is assigned, but the required number of memory blocks is 1. If variable E is assigned to the area following variable D, variable E will use up one memory block. Therefore, variable E is assigned to 0x12-0x13, which is the same memory block.

As a result of this allocation, the number of memory blocks in Figure 6 is 5, which is a reduction in memory blocks compared to the case where the number of memory blocks is 6 under allocation rule 3 in Figure 5.

As processing is performed in groups, allocation does not necessarily occur in the order of the allocation information 22, such as variable A being allocated followed by variable C. It is also possible to specify the memory block to be allocated for each group.

(Allocation based on update frequency)
The update frequency of each variable may be included in the setting items of the allocation information 22. That is, the acquisition unit 21 further acquires the update frequency of the variable.

The allocation unit 23 determines whether multiple variables can share a single memory block based on their update frequency, and allocates the variables accordingly. At this time, the conditions for determining whether multiple variables can share a single memory block may be set arbitrarily. In other words, when a single memory block contains at least two or more variables, the update frequency of one variable is compared with the update frequency of the other variable, and the multiple variables are allocated according to predetermined conditions.

Conditions include, for example, a combination in which variables with the same update frequency can be allocated to a single memory block. Also, a combination in which low-frequency variables cannot share the same memory block with medium-frequency and high-frequency variables, but medium-frequency variables can share the same memory block with high-frequency variables, etc. Conditions are not limited to these patterns, and any combination can be envisioned. Furthermore, because a single memory block will be shared by multiple variables, allocation rule 3 will be used.

In addition to the allocation unit 23, the warning unit 24 may also perform processing according to the update frequency. When a single memory block contains at least two variables, the warning unit 24 compares the update frequency of one variable with the update frequency of the other variable, and issues a warning according to predetermined conditions.

Therefore, when multiple variables share a single memory block, the allowable combinations of variables can be limited depending on the update frequency of the variables assigned to that single memory block.

For example, if a variable that is updated frequently and a variable that does not need to be changed after being written once share a single memory block, the lifespan of the RFID tag 4 may be sufficiently guaranteed. However, if a variable that is updated frequently at one time and a variable that is updated frequently at another time share a single memory block, it may not be possible to guarantee the lifespan of the RFID tag 4. By taking the update frequency into consideration, such cases can be prevented. As a result, a longer lifespan of the RFID tag 4 can be achieved.

Two specific conditions are given below, but the conditions are not limited to these. The conditions given are conditions under which the warning unit 24 issues a warning based on a combination of variables when multiple variables share a single memory block.

Figure 7 shows a condition table that determines whether to issue a warning under certain conditions when multiple variables share a single memory block. Figure 8 shows a condition table that determines whether to issue a warning under different conditions when multiple variables share a single memory block.

Under the conditions in Figure 7, the warning unit 24 issues a warning when a combination of low-frequency and medium-frequency or high-frequency variables shares a single memory block, or when a combination of medium-frequency and high-frequency variables shares a single memory block. In other words, a warning is issued when multiple variables with different update frequencies share a single memory block.

In this case, since the update frequencies are different, it is highly likely that the variables are updated at different times, which is thought to lead to a shortened lifespan of the RFID tag 4.

Furthermore, under the conditions in Figure 8, the warning unit 24 issues a warning if there is any combination in which a low frequency and a medium or high frequency share a single memory block, a combination in which a medium frequency and a low frequency, a medium frequency or a high frequency share a single memory block, or a combination in which a high frequency and a low frequency, a medium frequency or a high frequency share a single memory block. In other words, a warning is issued if multiple variables exist in the same memory block at a medium frequency or higher.

In this case, if the update frequency is medium or higher, the variable is likely to be updated many times, and if multiple variables share a single memory block, the memory block may reach the end of its lifespan. Therefore, it is believed that this will shorten the lifespan of the RFID tag 4.

Here, low frequency refers to a frequency at which the number of updates is not expected to reach the end of its lifespan, medium frequency refers to a frequency at which the number of updates is not expected to reach the end of its lifespan when used alone, and high frequency refers to a frequency at which the number of updates is expected to reach the end of its lifespan when used alone. Therefore, if a medium-frequency variable and another medium-frequency variable share a single memory block, it is possible that the end of its lifespan may be exceeded, shortening the lifespan of the RFID tag 4. Furthermore, only once refers to a variable that is updated only once and is not updated thereafter; examples include information such as a serial number or manufacturing date that identifies the managed object.

§5 Actions and Effects Each variable is allocated to the required number of memory blocks by the allocation unit 23 appropriately modifying the allocation information 22 acquired by the acquisition unit 21. Therefore, each variable can be accessed with the minimum number of memory accesses, resulting in efficient memory access.

Allocation rule 2 also allows only a single variable to be assigned to a single memory block, thereby extending the lifespan of the RFID tag 4. Allocation rule 3 allows multiple variables to be assigned to a single memory block, thereby saving memory and enabling high-speed memory access to multiple variables.

Furthermore, by adding additional information such as group or update frequency to the allocation information 22, allocation can be performed taking into account the update timing and lifespan of the RFID tag 4.

[Software implementation example]
The functions of the server 2 or the allocation device (hereinafter referred to as the "device") can be realized by a program that causes a computer to function as the device, and a program that causes a computer to function as each control block of the device.

In this case, the device includes a computer having at least one control device (e.g., a processor) and at least one storage device (e.g., a memory) as hardware for executing the program. The functions described in each of the above embodiments are realized by executing the program using this control device and storage device.

The above program may be stored non-transitory on one or more computer-readable storage media. These storage media may or may not be included in the device. In the latter case, the program may be supplied to the device via any wired or wireless transmission medium.

Furthermore, some or all of the functions of each of the above control blocks can be realized by logic circuits. For example, integrated circuits incorporating logic circuits that function as each of the above control blocks are also included in the scope of the present invention. In addition, the functions of each of the above control blocks can also be realized by, for example, a quantum computer.

Furthermore, each process described in each of the above embodiments may be executed by AI (Artificial Intelligence). In this case, the AI may run on the control device, or on another device (for example, an edge computer or a cloud server).

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

1 RFID system 2 Server (allocation device)
3 Reader/writer 4 RFID tag 21 Acquisition unit 23 Allocation unit 24 Warning unit

Claims (9)

An RFID system using an RFID tag that performs memory access for each memory block, which is an address unit of a predetermined block size,
an acquisition unit that acquires a plurality of variables to be allocated to the memory of the RFID tag and the size or address range of each variable;
an allocation unit that allocates the variable to memory so that the number of memory blocks used by the variable is the number of memory blocks required to allocate the variable, which is determined from the size or address range of the variable. The RFID system described in claim 1, wherein the allocation unit allocates a different memory block for each variable. The RFID system of claim 1, wherein the allocation unit allocates the second variable to another memory block rather than to the memory block to which the first variable is allocated, if allocating the second variable to the area following the area to which the first variable is allocated would result in the number of memory blocks used by the second variable being greater than the required number of memory blocks. The RFID system described in any one of claims 1 to 3 further comprises a warning unit that issues a warning if the number of memory blocks used by the variables assigned by the user is greater than the number of required memory blocks. the acquisition unit further acquires information on a group including a plurality of the variables;
The RFID system according to claim 1 , further comprising a warning unit that issues a warning when the variables that belong to different groups are assigned to a single memory block. The acquisition unit further acquires an update frequency of the variable,
The RFID system according to any one of claims 1 to 3, further comprising an alarm unit that, when a single memory block contains at least two or more of the variables, compares the update frequency of one variable with the update frequency of another variable and issues an alarm according to predetermined conditions. The RFID system described in any one of claims 1 to 3 further comprises a warning unit that issues a warning if the variable is assigned outside a predetermined memory area. An allocation device that allocates memory to an RFID tag that accesses memory for each memory block, which is an address unit of a predetermined block size, comprising:
an acquisition unit that acquires a plurality of variables to be allocated to the memory of the RFID tag and the size or address range of each variable;
an allocation unit that allocates the variable to memory so that the number of memory blocks used by the variable is equal to the number of memory blocks required to allocate the variable, which is determined from the size or address range of the variable. an acquisition step of acquiring a plurality of variables to be allocated to the memory of the RFID tag and the size or address range of each variable;
an allocating step of allocating the variable to memory so that the number of memory blocks used by the variable is the number of memory blocks required to allocate the variable, which is determined from the size or address range of the variable.