A put-to-light system is a reversal of the DPD function in the pick-to-light system, as the DPDs guide the worker visually to the containers where the articles making up each order are to be put.

It is a system for manual sorting, guided by illuminated DPDs.

As with the pick-to-light system, each location or container assigned to one article or SKU (Stock Keeping Unit) has an associated DPD. The most common model is a DPD with an illuminated button which visually guides the picker to each location and allows him to confirm the operation.

Advantages

Accuracy in sorting /order confirmation operations
Physical space saving
Flexibility for sorting different types of articles.
Prevents damage to products


Usual procedure

The control software assigns an order to each container on the shelf, linking each order to a DPD address.
The picker identifies the article using a barcode scanner directly connected to a twin wire system.
The DPDs light up to show which containers the articles need to go to, and the amounts.
The picker confirms each operation by pressing the DPD confirm button. This switches off the completed DPDs and if necessary informs of any deviations between the amount requested and the amount available. The system registers this incident and includes it in its report.
The DPD may light up in a different colour (green, for example), to inform the picker that the order has been completed.
The picker then removes the container so it can be shipped.


Problem-solving

Lack of space
Need for greater productivity
Limited production and storage capacity
Greater frequency of small orders
Picking cycles too long
Too many errors when consolidating orders