Physical inventory or cycle count
A physical inventory counts the entire warehouse on one date, usually at the close of a period. A cycle count counts one part at a time on a schedule. RFID supports both: the same read by sections counts one zone this week or the entire warehouse at year-end.
The procedure in this guide applies to both cases. Only the scope of each count changes.
Before you start: what must be ready
- Tags on the goods. Each item, case or pallet to be counted carries an RFID tag with its EPC registered in the system. An unregistered tag is read, but the system cannot identify it.
- Tags suited to the product. Metal and liquids affect reads and require tags designed for them.
- An on-site test. Before tagging all of the stock, the read is tested in the actual locations, with the product and the reader that will be used.
- Coded locations and stock recorded by location, so that what is read can be compared with what is expected.
Step 1: tag
Tags can arrive from the supplier or be printed and encoded at receiving on an RFID printer. If they are printed from the system, each EPC is registered and linked to its product, lot, serial number or pallet at the same moment. For goods already in the warehouse, tagging is done by zone, before the first count.
Step 2: prepare the count
The count is created by zone, the RFID method is selected and the count is divided into sections, each one the size a person can walk without interruption. The sections are assigned to the team that will read them.
Step 3: read each section
Each operator claims their section on the handheld and walks the locations with the reader. An orderly route works best, by aisle and by level, at a constant distance from the racks. The progress shows what is expected, what was found and what is missing, so the operator can return to a location before closing the section.
Step 4: review the discrepancies
On closing, each read is classified:
| Result | Meaning | Action |
|---|---|---|
| Found | The item was read in its location | None |
| Misplaced | The item was read in a location other than the recorded one | Move it or correct the record |
| Missing | The item was not read | Search for it and read again before adjusting |
| Unknown | The tag is not registered | Identify the item and register its tag |
A missing item in an RFID count is not always a lost item: it can be a tag covered by metal or outside the reader's range. For that reason, the section is read again before any adjustment.
Step 5: adjust and close
Adjustments are applied by a person with authority, with the reason for each discrepancy. Misplaced items are moved in the system or physically returned to their location.
Required equipment
- Handheld RFID reader: a sled that connects to a handheld, or a handheld with a built-in reader.
- RFID printer, if tags are printed and encoded in the warehouse.
- UHF RFID tags suited to each type of product.
To estimate the cost of each part, see how much RFID costs in a warehouse.
How it works in Chainlink WMS
In Chainlink, an RFID inventory is a count by zone with the RFID method, in Professional and Enterprise. On the handheld, the operator claims a section and the app opens a read session: reading continues while the trigger is held and pauses when it is released. When the section is closed, each item read is added to the count. Unknown tags are reported under RFID discrepancies, and an Administrative user applies the adjustments. The field-verified device is the Zebra TC27 with the RFD40 sled. See RFID inventory.