December 20, 2023
December 20, 2023

Optimizing Efficiency: Understanding Put-to-Light Picking Systems

Among the various technologies revolutionizing warehouse operations, put-to-light systems have emerged as a game-changer. Let's delve into the intricacies of put-to-light systems, exploring their functionality, benefits, applications, and potential challenges.

Arvato worker picks item from AutoStore Port and carries to put cart.

What is a put-to-light system?

Put-to-light is an advanced method employed in warehouses or distribution centers to streamline the picking process. It utilizes light displays, indicating the specific locations where items need to be placed or "put" after being picked for a particular order.

The implementation of a put-to-light system can take place either directly on picking shelves or integrated into carts, optimizing the efficiency of pick-to-cart operations. This innovative system functions by equipping each container with an associated light, facilitating the order preparation process. As orders are processed, the relevant location display illuminates, guiding operators precisely where to place the goods and the specific quantity required.

This advanced system operates in conjunction with a warehouse management system (WMS), acting as the central coordinator for the light displays and automating critical decision-making processes. Seamlessly connected to the WMS, the put-to-light system directs operators to the designated box for depositing goods, displaying the required quantity of the SKU on the LED interface. Additionally, the software interfaces with RF scanners utilized by operators to scan and sort products efficiently.

Primarily employed to minimize errors inherent in batch picking procedures, where operators distribute varied quantities of a single SKU across multiple orders, put-to-light systems significantly enhance accuracy.  

To expedite the supply of goods to pick stations during order sorting, warehouses can implement box conveyors. These conveyors facilitate the continuous flow of stock, complementing the put-to-light system and ensuring uninterrupted stock movement for efficient order fulfillment.

How does it work?  

At its core, a put-to-light system involves bins or totes equipped with light modules. While there are variations, this is how the standard technology works:

  1. When an order is generated, the system directs the picker to the required items using digital displays or indicators.  
  2. Once the picker retrieves the items, they place them into the corresponding bins that illuminate to guide the placement.  
  3. The system confirms successful placement and can signal the picker for the next task.

Benefits of implementing a put-to-light system

The benefits of put-to-light are multifaceted, addressing key challenges inherent in traditional picking methods. These systems go beyond mere illumination, offering a strategic blend of technology and streamlined processes that redefine the landscape of order fulfillment. From expediting workflows to enhancing accuracy and adaptability, put-to-light systems emerge as indispensable tools for modern warehouses seeking optimized performance and sustained growth.

  • Enhanced Efficiency: By providing clear visual directives, put-to-light systems expedite the picking and placing process, minimizing time spent per order.
  • Error Reduction: Visual indicators significantly reduce misplacements, improving order accuracy and reducing errors common in manual picking methods.
  • Adaptability: These systems can accommodate various order profiles and SKU ranges, ensuring flexibility in handling diverse inventory.
  • Real-time Tracking: Offers real-time visibility into order status and inventory levels, enabling proactive management and reordering.
  • Scalability: Designed to handle increased order volumes and easily adaptable to warehouse expansion.

Differences from other operations

Pick-to-light system illuminating product in AutoStore Bin
A pick-to-light system illuminates product inside an AutoStore Bin.

Put-to-light systems share some similarities with two other material handling technologies but are nevertheless different in how they’re used:

  • Pick-to-Light: Similar in concept, but in pick-to-light systems, the lights indicate where to pick items rather than where to place them.
  • Voice Picking: Relies on voice commands to guide pickers, offering a hands-free approach compared to the visual cues of put-to-light.

Industries using put-to-light systems

Put-to-light systems find application across diverse industries such as e-commerce, retail, pharmaceuticals, and automotive sectors. Their versatility and accuracy make them indispensable in high-paced environments where precision and speed are paramount.

How put-to-light enhances accuracy and reduces errors

By providing clear visual guidance for item placement, put-to-light systems significantly reduce misplacements, thereby improving accuracy and minimizing errors common in traditional picking methods.

Key elements of put-to-light systems

Put-to-light systems comprise various integral elements meticulously designed to orchestrate the precision and efficiency required for seamless order fulfillment. From illuminating designated placement areas to providing directives via display units, managing order flow through a centralized control system, to seamless integration with warehouse management systems — each component plays a crucial role in enhancing accuracy and streamlining workflows within warehouse environments.

  • Light Modules: Integrated into bins or storage locations to indicate where items should be placed.
  • Display Units: Provide instructions and guide workers to the correct placement locations.
  • Central Control System: Manages and coordinates the flow of orders, ensuring seamless operation.
  • Software Integration: Interfaces with warehouse management systems for order management and tracking.

Potential challenges and mitigations

Implementation costs of a put-to-light system can be a challenge, but the ROI in efficiency gains justifies the investment. Proper integration with existing systems is crucial and requires meticulous planning and testing. Also, adequate training for staff on system use is essential to ensure smooth operations.

Factors to consider when selecting a put-to-light system:

When selecting an appropriate put-to-light system for your warehouse, it's essential to consider several factors to ensure the system aligns with your operational needs and budget.

Begin by assessing your warehouse's specific operational requirements. Evaluate the layout, picking methods, order volume, SKU variability, and workflow intricacies. Understanding these details will help determine the features and capabilities needed in a put-to-light system to meet your warehouse's demands effectively.

Scalability is another crucial consideration. Ensure that the selected put-to-light system can handle your current order volumes and possesses the flexibility to accommodate future growth or seasonal fluctuations. A scalable system can adapt to changes in your business without significant disruptions or additional costs.

Check for integration capabilities. It's imperative that the chosen put-to-light system seamlessly integrates with your existing warehouse management or operational systems. Compatibility and smooth data exchange between systems are essential for efficient operations.

Evaluate the customization and flexibility offered by the system. Determine if it can be tailored to fit your unique warehouse requirements and workflows. A system that allows for customization ensures adaptability to changing operational needs and processes.

User-friendliness and ease of training are vital aspects. Consider the simplicity of the put-to-light system's interface and the ease with which your warehouse staff can be trained to operate it efficiently. A user-friendly system minimizes training time and reduces errors during implementation.

Reliability and support from the vendor are critical. Assess the quality of support services offered, including maintenance, updates, technical assistance, and overall customer support.

The cost of a put-to-light system

When considering costs, remember the various components involved. These include hardware costs (light modules, displays, control systems), software and integration expenses, installation and implementation costs, and ongoing maintenance and support expenses. Request detailed quotes from multiple vendors, ensuring clarity on all associated costs.

Finally, conduct a thorough cost-benefit analysis. Estimate the potential ROI by weighing the expected benefits, such as increased efficiency, reduced errors, improved order accuracy, and faster order fulfillment, against the initial investment and ongoing operational expenses. This analysis will help in making an informed decision based on both short-term costs and long-term benefits.

Integration of put-to-light with your existing systems

Integrating a put-to-light system with an existing warehouse management system (WMS) or operational setup involves several steps to ensure seamless functionality and data exchange. Here are 10 steps to integrating a put-to-light system with your existing infrastructure:

1. Assess Current System Capabilities: Before integration, evaluate your existing WMS or operational setup to understand its compatibility and capabilities to support the integration of a put-to-light system. Identify potential areas for modification or enhancement if necessary.

2. Compatibility Check: Ensure that the put-to-light system you intend to integrate is compatible with your current infrastructure. Confirm compatibility regarding hardware, software, communication protocols, and data exchange formats.

3. Planning and System Design: Develop a detailed integration plan outlining the specific functionalities and data exchange points between the put-to-light system and your existing setup. Define how information will flow between systems, including order data, SKU information, pick lists, and status updates.

4. Customization and Configuration: Work with the put-to-light system provider or an integration specialist to customize and configure the put-to-light system according to your warehouse's specific needs and operational workflows. This may involve programming logic, setting up user interfaces, and configuring data mapping.

5. API or Middleware Integration: If your existing system supports application programming interfaces (APIs) or middleware, utilize these to facilitate seamless communication between the put-to-light system and your WMS. APIs allow for data exchange, enabling real-time updates and synchronization of information between systems.

6. Data Mapping and Translation: Establish data mapping protocols to ensure that data transferred between systems is correctly interpreted and formatted. Define how data fields (such as SKU codes, order details, bin locations) will be mapped between the put-to-light system and the WMS to avoid discrepancies.

7. Testing and Validation: Thoroughly test the integrated system in a controlled environment to validate its functionality, accuracy, and reliability. Conduct various scenarios to ensure that data transfer, order processing, and communication between systems work flawlessly.

8. Staff Training: Provide comprehensive training to warehouse staff and operators involved in using the integrated put-to-light system. Ensure they understand the new processes, user interfaces, and how to interpret visual cues provided by the put-to-light system.

9. Go-Live and Continuous Monitoring: Once the integration is complete and tested, initiate a controlled go-live phase to implement the integrated put-to-light system into your operational environment. Monitor the system closely post-implementation for any glitches or issues that may arise and address them promptly.

10. Ongoing Maintenance and Updates: Regularly maintain and update the integrated system to ensure optimal performance. Stay in touch with the put-to-light system provider for updates, enhancements, or troubleshooting assistance as needed.

By following these steps and working closely with both your existing system's technical team and the put-to-light system provider, you can effectively integrate a put-to-light system into your warehouse operations, improving efficiency and accuracy in order fulfillment processes.

How the integration with an Autostore works

Put-to-light systems typically integrate with AutoStore through software like a WMS. In this scenario, the put-to-light hardware is programmed to communicate with the WMS that coordinates the whole put-to-light process. Once operational, orders to be fulfilled are assigned to a specific Port according to various logics, including commonality between SKUs, different shipping priorities, or product family restrictions.

Robots fetch a requested Bin, each of which contains a different order line to be fulfilled. A picker retrieves the required quantity of items from the Bin and puts them into a shipping carton or temporary storage, such as a picking cart that holds multiple orders. The cart has an alphanumerical display that shows the exact number of items that need to be placed. Once the operator has placed all requested items onto the cart, they press a button next to the display to confirm task completion. Subsequently, a new batch of orders will replace the fulfilled orders, and the process will continue, one batch after the other.

Put-to-light with AutoStore: a real-world example

Arvato, a 3PL provider in the Netherlands, has mastered the integration of put-to-light technology with AutoStore empowered by Swisslog. Here’s how it works:

Incoming orders are assigned to a put-to-light pick cart by Swisslog’s SynQ WMS, in the most logical order. The system indicates which of the six standard carton sizes orders will be picked. Up to 30 orders can be picked per cart.

Arvato worker carrying items from AutoStore Port to put cart.
Running an integrated AutoStore and put-to-light solution with Swisslog's SynQ WMS allows Arvato to process over 25,000 daily orders for Rituals Cosmetics.

The order picker first walks the cart through the fastmover lane, where triple A orders and larger products are assigned to the correct order box. Next, the carts are placed at the picking stations of the AutoStore system where the orders are completed using the put-to-light principle. Four carts per station, i.e. 120 orders, can be picked simultaneously. The SynQ interface is configured to display the status of orders clearly and briefly.

The system is integral to a 24/7 operation capable of processing over 25,000 orders per day on behalf of Rituals Cosmetics.


In conclusion, put-to-light systems can significantly improve warehouse efficiency, order accuracy, and throughput. While they come with initial challenges, the long-term benefits make them a vital tool in the ever-evolving landscape of logistics and supply chain management.


What does put to light mean?

Put-to-light refers to a technology utilized in warehouse or distribution center operations. It involves a system of lights and displays that guide workers to the precise locations within the facility where items should be placed after they've been picked for specific orders. The system uses visual cues to direct workers to the correct bins or locations for item placement, streamlining the final stages of order fulfillment.

How do workers use put-to-light system?

Individuals in these roles are responsible for placing items into designated bins or locations indicated by the light system after they've been picked by other workers. Their primary duty is to ensure accurate and efficient placement of items, following visual cues provided by the put-to-light system.

What is pick-to-light and put to light?

Pick-to-light and put-to-light are similar technologies used in warehouse operations but differ in their primary functions.

Pick-to-light systems guide workers to the specific locations within a warehouse where items need to be picked for orders. Lights indicate the picking locations, helping workers identify and retrieve the correct items.

Put-to-light systems, on the other hand, guide workers to the precise locations where items should be placed after being picked. Lights and displays direct workers to the designated bins or areas where items must be deposited, ensuring accurate placement for order fulfillment.

While pick-to-light focuses on picking items for orders, put-to-light concentrates on the placement of items once they've been picked, optimizing the final stage of the order fulfillment process. Both systems contribute to improving accuracy, efficiency, and speed in warehouse operations but serve different functions in the overall workflow.

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