System structure of a Pick-to-Light system

The logical structure of a Pick-to-Light system is very clear and structured in several hierarchical levels. In this article we explain the individual levels and show you how flexible and different the structure can be set up.

Different types of addresses in the system structure

A large Pick-to-Light system can consist of several thousand displays. Each display and each controller has a globally unique hardware address. The address is stored during production and cannot be changed.

The hardware address as the basis of the system structure

Because each system component has a unique address, hierarchical levels can be built up in the system structure. This means that a controller can not only address displays, but also subordinate controllers. The system thus forms a cascade with several levels.

The individual units are identified and controlled via the address chain. If a component recognises its own address, it is checked whether addressing is completed or not. Depending on this, the command is processed or forwarded to the subordinate level (further controllers or Pick-to-Light compartment displays).

The management of the structure and its address chains is regulated by the software in the LUCA-Server . A logical address (alias) has been inserted to enable simple addressing of the hardware components.

The logical address

The logical address is a unique name (alias) of the Pick-to-Light component and is independent of the system structure. Usually, the logical addresses of the Pick-to-Light-subject displays are used as zone name + storage location (e.g. Z01-A12-E02).

Each Pick-to-Light shelf display is given a unique name for control by the warehouse management system.

Feedback in this hierarchy

The entire Pick-to-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 therefore holds all the hardware addresses of its children, which it constantly polls.

Through the permanent polling of the structure, the status and feedback is forwarded to the higher level up to LUCA-Server .


Does the warehouse management system need to know the system structure of the Pick-to-Light system?

No. The entire structure of the Pick-to-Light system is mapped and managed in the LUCA-Server . Each Pick-to-Light compartment display (independent of the structure level) is given a logical address. The WMS controls the display via this address (storage location designation).

What happens to the system structure when a display or controller needs to be replaced?

When replacing a Pick-to-Light display, the new display gets the same logical address and the storage compartment can be controlled exactly as before. When replacing a controller, the addresses are simply rewritten automatically when the system is started.

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