Warehouse Management Systems (RFID)

Tags

The lower-cost tags generally are passive (meaning they have no internal power source),
have limited data storage capacity (typically 32 to 128 bits), are read-only (not rewriteable),
and have limited read range. Like bar codes, they are usually used as "license
RFID Technology for Warehouse and Distribution Operations
plate" identifiers, i.e., they hold little actual data but serve to identify the object to a
database containing larger amounts of information. For example, a tag attached to a
product in a work-in-process application would uniquely identify the product each time it
passed by a reader. The reading, and any work performed on the assembly, would be
recorded in a database. In turn, a conveyor-based sortation system could identify the item
and receive routing instructions from a database application, allowing products to reach
their loading destination without human intervention.
Higher-cost tags are available for many more complicated longer read applications. They
often have their own power source (these are known as active tags), making them heavier
than passive tags, and large data storage capacities (upwards of 1M), making them
essentially self-contained databases. These higher-capacity tags could, for example,
monitor temperature through a process or give operational instructions to a robotic
workstation when they arrive attached to their item, then have updated status information
appended to the tag when the task is complete. This flexibility does have a cost, however;
the internal power source can burn out, giving these tags a life span of 5-10 years.