System structure of a pick-by-light system
The logical structure of a pick-by-light system is very clear and organized into several hierarchical levels. In this article, we explain the individual levels and show how flexible and varied the structure can be.
Different types of addresses in the system structure
A large pick-by-light system can consist of several thousand displays. Each display and each controller has a globally unique hardware address. The address is permanently stored during production and cannot be changed.
The hardware address as the basis of the system structure
Since each system component has a unique address, hierarchical levels can be established in the system structure. This means that a controller can address not only displays but also subordinate controllers. The system thus forms a cascade with several levels.
The individual devices are identified and controlled via the address chain. When a component recognizes its own address, it checks whether the addressing is complete or not. Depending on this, the command is processed or forwarded to the lower level (other controllers or pick-by-light compartment displays).
The structure and its address chains are LUCA-Server by the software in the LUCA-Server . A logical address (alias) has been added to enable easy addressing of the hardware components.
The logical address
The logical address is a unique name (alias) for the pick-by-light component and is independent of the system structure. The logical addresses of the pick-by-light compartment displays are usually used as zone name + storage location (e.g., Z01-A12-E02).
Each pick-by-light compartment display is given a unique name for control by the warehouse management system.
Feedback in this hierarchy
The entire pick-by-light system operates in a cascaded polling mode. Each controller (parent) checks the status and feedback of its subordinate components (children). To map the structure, each controller stores all the hardware addresses of its children, which it constantly queries.
The status and feedback are LUCA-Server to the higher level up to the LUCA-Server through continuous polling queries of the structure.
FAQ
Does the warehouse management system need to know the system structure of the pick-by-light system?
No. The entire structure of the pick-by-light system is LUCA-Server and managed in the LUCA-Server . Each pick-by-light compartment display (regardless of the structure level) is assigned a logical address. The WMS controls the display via this address (storage location designation).
What happens to the system structure if a display or controller needs to be replaced?
When replacing a pick-by-light display, the new display is assigned the same logical address and the storage compartment can be accessed in exactly the same way as before. When replacing a controller, the addresses are simply rewritten automatically when the system is started.
