Balluff BIS M-370-000-A02, Manual, Page: 194 / 198

RFID OPERATING PRINCIPLES
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High temperature (HT) tags, using patented processes and specialized materials, allow tags
to survive elevated temperatures, such as those found in automotive paint and plating
applications. Balluff offers a wide variety of molded tags that have been developed over the
years for real world applications.
RFID TAG MEMORY
RFID Tag memory addressing typically begins at tag address zero (0x00), with the highest
addressable memory location equal to one less than the total number of bytes in the tag.
Each address location is equal to one byte (8-bits), where the byte is the smallest
addressable unit of data. So for example, writing 8-bytes to a tag beginning at address 0x00
will actually fill addresses 0x00 through 0x07 with 64-bits of data in all.
Depending on the manufacturer, RFID labels, molded tags and embedded PCBs can have
differing memory storage capacities and organization. Tag memory is grouped into blocks of
bytes that can vary in structure from manufacturer to manufacturer. Even when compliant to
ISO standards, byte memory addressing can differ from one manufacturer to another. For
example, tag memory can be organized in blocks of 4 or 8 bytes, depending on the RFID IC.
Additionally, all bytes may not be available for data storage as some bytes may be used for
security and access conditions.
Balluff has taken great care to simplify tag memory addressing. The mapping from logical
address to physical address is handled by the BIS M
Controller’s operating system. Users
only need to indicate the starting address location on the tag and the number of bytes to be
read or written.
Mapping Tag Memory
Creating a Tag Memory Map is much like designing a spreadsheet that outlines the actual
data you plan to capture as well as the specific tag memory locations in which you wish to
store said data. Tag Memory maps should be carefully planned, simple and straightforward.
It is advisable to allow additional memory space than is initially required, as inevitably a need
will arise to store more data.
In the example below, 90-bytes of a 112-byte tag have been allocated to areas of the
Memory Map (leaving roughly 20% free for future uses). Because a short paragraph of
alphanumeric characters could quickly use all 90 bytes, creating an efficient mapping
scheme that utilizes all 720-bits (out of the 90-bytes allocated) will provide a better use of tag
space.
Tag Memory Map Example
Tag Address Usage
00
– 15
Serial Number
16 - 47 Model Number
48 - 63 Manufacturing Date
64 - 71 Lot Number
72 - 89 Factory ID
90 - 111 Reserved for future use