Radio Frequency Identification (RFID) is a technology that allows items to be labeled with RFID tags and the tags to be automatically read when passing within the vicinity of an RFID antenna and reader. Tags can be read through a variety of substances such as paint, grime, and other visually and environmentally challenging conditions, where barcodes or other optically read technologies would be useless. RFID tags can also be read in challenging circumstances at remarkable speeds, in most cases responding in less than 100 milliseconds.
The micro broker has been used in a retail solution for tracking the location of pallets in shops, warehouses, and distribution centers. The aim being to ensure the location of pallets is known at all times and to ensure that pallets are delivered to the correct store in a timely manner.
The architecture is comprised of four tiers:
These are found at the edge of the network, and include components such as RFID readers, motion sensors, and light stacks.Edge server
This is a small footprint computer that handles connectivity and manages the devices. Monitoring, control and notifications together with business logic for implementing RFID use cases is handled by the edge server.Premises server
This system manages a retail location, warehouse, or distribution center. Multiple edge servers may be connected to a premises server.Enterprise server
This is the “back-office” system that manages global information from all premises servers.
A basic use case validates that a pallet being delivered is expected at the location. The pallet is removed from the delivery vehicle and moved into the warehouse through the dock bay doors. A motion sensor located at the dock bay door detects the pallet is moving into the warehouse. This results in the edge server sending a control command to activate the RFID reader. Once the pallet has moved into to the RFID field, the reader reads the tags and sends them to the edge server. A tag may be read multiple times, producing multiple messages to the edge server. The edge server filters the tag data, performing tasks such as removing duplicate tag readings. The filtered tag data is then sent to the premises server for validation. The premises server checks with a repository to confirm that the tag is expected in this retail location. This process may require an exchange with message the enterprise server to perform the validation). The result is sent back down to the edge server. If the pallet (tag) is expected, then a green light is switched on and the pallet is accepted into the warehouse. If not, a red light is switched on, and the pallet is returned to the delivery vehicle.
At the edge server, every device has an agent that contains an MQTT client. The agent receives output from the device, creates well-defined messages that are sent to the micro broker on the edge server, and accepts command and control messages that are mapped to the device sensors and actuators.
Certain messages are routed to the premises server for processing. In this example, a tag is sent to the premises server to validate that it is expected at this retail location. The micro broker accepts messages destined for the premise servers and ensures the message is delivered to another micro broker on the premises server. Typically, a bridging component in the premises server micro broker is then used to route messages, destined for the back-office enterprise level servers to be processed.
Parent topic: Scenarios and applications