Reading RFID data involves more than just having a reader detect a tag. In practical applications, it is necessary to distinguish between the EPC code, the TID (chip identification information), and the data stored in the User memory bank, while also ensuring that this data can be correctly parsed by the business system. For projects such as warehouse inventory, asset tracking, and logistics management, understanding how RFID data is stored is fundamental to debugging readers and establishing data collection workflows.
According to the GS1 EPC Tag Data Standard, tags compliant with RAIN RFID / UHF Gen2 specifications utilize different logical memory banks to store identification information and supplementary data. Before reading, one must verify the tag type, chip model, supported memory banks, and whether the reader supports the necessary commands for accessing those specific areas.
1. What data can be read from an RFID tag?
Taking a common UHF RFID tag as an example, the storage structure typically consists of four logical memory banks; however, the actual available capacity, data content, and access permissions depend on the specific chip model and tag configuration.
| Memory Bank Name | Primary Purpose |
| Reserved Memory | Stores the Access Password and Kill Password |
| EPC Memory | Stores the Electronic Product Code (EPC), used to identify items or assets |
| TID Memory | Stores information about the chip manufacturer and the tag's unique chip identifier |
| User Memory | Stores optional, supplementary business data |
It is important to note that an EPC is not equivalent to the complete information about a product. For instance, after reading an EPC code, one typically needs to query a database to retrieve associated details such as product numbers, batch information, warehouse locations, or asset records. If the tag's User Memory contains data like temperature readings or expiration dates, this information must be decoded according to specific encoding rules to become human-readable.
2. How is RFID tag data read?
Step 1: Select a compatible RFID reader. Choose a device based on the tag's operating frequency and protocol. For example, UHF RFID tags generally require a reader compatible with the EPC Gen2 / ISO 18000-63 standard, while NFC tags require an appropriate high-frequency (HF) reader. Although some smartphones can read certain NFC tags, they cannot serve as a direct replacement for professional RFID readers.
Step 2: Initiate an inventory process. Use the reader's accompanying software or SDK to scan tags and retrieve identification information, such as the EPC. If you need to access chip-specific information or additional data, you must specifically select the functions for reading the TID (Tag Identifier) or User Memory. Note that some readers are configured by default to return only the EPC and will not automatically read all available memory banks.
Step 3: Parse the read results. Data returned by a reader may appear as a hexadecimal string, an EPC URI, or business-specific fields processed by the software. You must first verify the output format and then decode the data according to the relevant standards; do not simply treat all hexadecimal data as plain text.
Step 4: Integrate with business systems. Within systems such as Warehouse Management Systems (WMS), asset management systems, or ERPs, the EPC can be mapped to specific product or asset records. This allows RFID data to be used for tasks like inventory reconciliation, tracking the movement of goods, and managing asset status, rather than merely displaying a string of tag identifiers.
3. Why might RFID data fail to read or appear incorrectly?
If a reader can detect a tag but fails to read its User Memory, first verify that the chip actually contains that memory bank, ensure the read address and length are correct, and confirm that the access permissions are properly set. If an EPC appears as a hexadecimal string, check whether the software requires an EPC decoding step rather than a direct conversion to ASCII text.
If a tag cannot be detected at all, investigate factors such as operating frequency, protocol compatibility, antenna connections, reader power output, and the environment in which the tag is installed. Actual read ranges should not be judged solely by the reader's nominal specifications; they must be evaluated based on the tag's antenna design and the results of on-site testing.
4. Applications of RFID Data in Real-World Projects
During warehouse inventory audits, readers can identify multiple items or pallet tags-each with a unique EPC-and cross-reference these records against an inventory database. In industrial asset management, the TID can help identify the specific tag chip, while the EPC can be linked to an asset record. For applications requiring the storage of additional business-related data, the User Memory can be utilized, subject to the chip's capacity and relevant data encoding standards.
For large-scale deployments, it is advisable to coordinate the selection of tag chips, reader protocols, data formats, and software interfaces during the procurement phase. When selecting RFID tags and readers, Xminnov bases its evaluation on factors such as read range, tag mounting location, data storage requirements, and system integration methods-ensuring that the process goes beyond merely verifying whether an individual tag can be read, and instead accounts for subsequent system-level data parsing and compatibility.
