Balluff BIS M-370-000-A02, Manual, Page: 195 / 198

BIS M REFERENCE MANUAL
188
12
Optimizing Tag Memory
Data is stored in tag memory in binary
format (1’s and 0’s). Binary numbers are notated
using the hexadecimal numbering system (otherwise, users would be forced to interpret long
strings of 1’s and 0’s).
Below is an example of how hexadecimal notation simplifies the expressing of byte values for
the decimal number 52,882. Instead of using 5-bytes of data to store the ASCII bytes
representing characters 5, 2, 8, 8, and 2 (ASCII bytes: 0x35, 0x32, 0x38, 0x38, 0x32) by
simply writing two “hex” bytes (0xCE and 0x92), 60% less tag memory is used to store the
same information.
Decimal Binary Hexadecimal
52,882 1100111010010010 CE92
When an alphabetical character is to be written to a tag, the Hex equivalent of the ASCII
value is written to the tag. So for example, to write a capital “D” (
ASCII value 0x44 ), the Hex
value 0x44 is written to the tag.
In addition, when a database with look up values is used in the RFID application, the logic
level of the individual bits within the tag can be used to maximize tag memory even further.
The graphic below illustrates how a single byte (8-bits) can be efficiently used to track an
automobile’s inspection history at eight inspection stations. The number one (1) represents a
required operation and the number zero (0) represents an operation that is not required for
that particular vehicle.