Pick by Light

The ultimate system for picking, sequencing, assembly and production

What is Pick by Light it?

Planning and setting up a Pick by Light System?

What hardware and software does a Pick by Light system need?

Pick by Light yourself?

...and much more.

We will give you an answer to all these questions here. We also supply professional picking systems with Pick by Light. All our systems are controlled by the central LUCA-Server. In this article you will find the most important information, technical details, application examples and prices for our Pick by Light. This guide is addressed to planners, technicians and buyers. Please take your time and read this article carefully.

In this and many other blog posts we explain to you ourselves how to correctly plan, buy and introduce our Pick by Light. Not only do we give you a few tips, but we also explain in detail how you can increase the performance of your picking while minimizing error rates. Follow us in the blog newsletter and on social media and recommend this article to others.

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But why is the Pick by Light so special? What distinguishes the system from the other picking systems? How is a modern Pick by Light structured? Where is the system best used and what costs do you have to expect? We will give you the answers to all these questions. Let us start ...

What is a Pick by Light System?

Pick by Light is a system with electronic displays on storage compartments and is used for picking, sequencing and packing of articles in a warehouse or production. For this purpose, a small device with LEDs, a display and several keys is mounted on each storage compartment and connected to the controller via a BUS.

For newcomers, a brief guide before we start with the details. Pick by Light is a very fast and error-free method for picking, sequencing and production. Once the order is activated, the LEDs and displays directly at the storage compartments light up accordingly. This enables the employee to find his storage compartments very quickly and confirm the activity directly there.

There are many variants and different process sequences, which we design according to customer requirements. We develop and deliver professional solutions with Pick by Light. In the display gallery you will find our currently available displays. Further general information can also be found on Wikipedia.

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What is paperless picking?

In paperless picking, a computer system directly supports the employees. There are no more paper lists! Many different technologies support paperless picking (see all LUCA systems). This Pick by Light is one of the most effective and successful paperless, manual picking systems worldwide.

In a conventional warehouse, employees pick with paper lists and mark each order item on the list with a ballpoint pen. Not only the speed but also the quality depends very much on the personnel. The employees search the storage compartments and can quickly make a mistake.

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Performance and quality with Pick by Light

Performance and quality are opposing parameters. As a result, the more performance is expected, the less quality can be guaranteed. So it is not very easy to increase performance and quality at the same time.

Pick by Light provides us with an excellent example of how performance and quality can clearly increase. The performance increases up to 40%. The targeted support of access to the storage compartments also increases quality by more than 15%. When using sensors on the displays, there is an additional 10%.

When planning a paperless picking system, it is essential to consider the economic efficiency. Pick by Light requires a relatively large amount of hardware, which makes the procurement of the equipment not exactly inexpensive. An ROI calculation must show whether the investment is profitable. Get in contact with us. We will help you to make the calculations.

If the demand for the performance is not particularly high and the storage areas are large, we alternatively supply other technologies for picking such as Pick by Scan, Pick by WatchPick by voice, etc.

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Pick by Light is simple and at the same time absolutely special!

Pick by Light itself is actually very simple. A display with LEDs and buttons is mounted on each storage compartment. Our central LUCA-Server controls the switching on of the displays and waits for user input on the keys. So at first glance this is nothing special.

Technically a modern Pick by Light one is a great marvel!

Not only the simultaneous communication with all displays is so special here, but also the reaction times after user input are crucial.

Our systems easily control several thousand displays simultaneously. The secret of the solution lies in the professional BUS system called PTF and the multitasking processing of the data in our LUCA-Server. PTF is the new standard for pick by light communication.

Pick by Light, Pick to Light oder Put to Light – was ist richtig?

Unsere Antwort lautet: alle Begriffe sind korrekt!

Wobei Pick by Light und Pick to Light werden oft als Synonyme verwendet, was eigentlich falsch ist. Selbst die Bezeichnung Pick to Light deutet schon auf eine Aktion, die etwas mit einer Abgabe zu tun hat. Pick to Light wird also oft als Bezeichnung einer Multi Order Picking Methode bei einem Pick by Cart System verwendet. Schließlich bei dem Begriff Put to Light handelt sich klar um eine Sortierung oder Nachschub.

Wir verwenden überwiegend den Begriff: Pick by Light, obwohl die anderen Begriffe ihre Berechtigung, je nach Funktion, auch haben.

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Where is it Pick by Light used?

The Pick by Light system is very versatile. The hardware itself (displays) only serve as output and input devices. The entire logic of the control system, as well as the process flow, takes place in our LUCA-Server instead. This makes our solutions very flexible and covers a very wide range of tasks. Customer-specific adaptations are possible at any time.

The following industries have been successfully using our systems for many years:

  • eCommerce: picking and replenishment in the dispatch warehouse
  • Automotive: sequencing of shopping baskets and JIT racks for the assembly lines
  • Production: assembly stations, set formation and machine assembly

Pick by Light is used wherever simple information is expected directly at storage compartments or at machines. The operator can make appropriate entries via various keys on the displays.

You can read more about the possible extensions of the Pick by Light system in the article: "Pick by Light System".

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eCommerce: picking and replenishment in the dispatch warehouse

In a dispatch warehouse, the Pick by Light is mostly used for picking A or B articles. This fast picking method brings enormous advantages for performance and quality. The use of conveyor technology in a material flow system further optimises the overall system.

When using the conveyor system, the shipping cartons automatically travel to the individual picking zones. The order is not activated until after they have been ejected and the appropriate displays light up. The strong LED signals the position from a great distance. Whereby the displays show the removal quantity directly. The employee then acknowledges the removal with a button directly on the display.

If the stock in the storage compartment does not fit, the employee can enter a message for a shortage directly on the display.

In addition to picking, the Pick by Light system is also used very successfully to support replenishment. Simple "Put to Light" displays are mounted on the individual supply channels in a shelf (e.g. https://www.luca.eu/ptf-l-6/). When replenishment orders are activated, the corresponding display lights up. The employee is guided directly to the correct storage compartment. Acknowledgement takes place via the button on the display or with the help of a scanner.

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AutomotiveSequencing of shopping baskets and JIT racks in the supermarket

Pick by Light plays a very large and decisive role in the preparation of the assembly as shopping baskets and JIT racks in an automotive plant. The large number of models and variants makes it impossible to store the car parts directly at the assembly line due to lack of space. For this reason, the car parts are also stored and "called off" in the neighbouring halls or even at distant service providers. These storage areas are often called supermarkets (SuMA). You can read more about the requirements of the automotive industry here: Automotive.

The assembly line of an automotive plant must be supplied 100% without errors and at the right time.

The preparation of car parts in the supermarkets is called sequencing. We will soon publish a separate article about sequencing in the automobile production itself. Stay tuned ...

Our systems and the LUCA-Server are specially developed for customers with high quality requirements and are perfectly suited for trouble-free continuous operation. The Quick-Click-System allows a quick and easy modification of the system. Thus the requirements for changing car parts (alternative parts) are easily met.

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Production: assembly stations, set formation and machine assembly

In production, the Pick by Light can be used in a particularly versatile way. Often not only one but several product variants are assembled on an assembly table. The components are usually provided at the assembly table in small or larger containers and cartons. A large number of product variants, as well as similar and confusing components, can lead to problems with quality and performance. The Pick by Light can be a very good help for this.

After activating the orders, the corresponding displays light up directly on the components. The entire assembly process is controlled by an existing system or by our LUCA-Server controlled. Not only access to the components is important here, but also the correct sequence of assembly. It is very important that the system supports the employee and, if possible, corrects any errors (PokaYoke). Additional sensors on the displays monitor the activities and immediately report errors in case of possible mix-ups.

Pick by Light can also be used very well for set formation and machine loading. However, these applications are very versatile and require precise process planning. We will be happy to answer any questions you may have in this regard.

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How is Pick by Light System structured?

Our system is highly modular and very flexible. All available displays can be used together. The main role of the control system is played by our LUCA-Server. In the server, we not only implement the communication to the displays, but also control the entire process logic, as well as the connection to the higher-level system and the additional components (e.g. scanner, RFID reader, machines, conveyor technology, etc.).

Here are the Pick by Light components:

  • LUCA-Server (often as a virtual Windows server)
  • Pick by Light - Controller (several BUS systems)
  • Mounting rails with integrated BUS system
  • Pick by Light - Displays with Quick-Click-System

Further information about the Pick by Light system and the extensions is available in a separate article: Pick by Light System

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pick by light controller

The individual displays must be supplied with power and data. This is ensured by the Pick by Light controllers connected to the Ethernet and power. Each controller is assigned to an IP address and is controlled by the LUCA-Server controlled.

pick by light controller
This controller can supply and control up to 400 displays.

A single controller has several BUS systems and controls (depending on the model) about 100 - 400 displays. The intelligent power supply of the controllers is designed in such a way that all displays can light up simultaneously. In such a cascaded system with several controllers, even more than 50,000 displays can function simultaneously.

The reaction times to the individual events are very short and are only a few milliseconds. In summary, the entire system is designed to be highly multitasking. This is exactly the reason why we can guarantee the fast response times.

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Mounting rails with integrated BUS

First, the BUS system is integrated into a mounting rail made of aluminium (here marked yellow). Second, a double clamp is installed at the mounting rail. The mounting rail is then connected to the controller with a 4-wire cable (plus, data signal, minus and ground) via the double terminal. The cable can then be led from the double terminal to another mounting rail. No cables are required between the individual Pick by Light displays! This makes our system so very flexible. The displays can be inserted at any position on the mounting rail. The cabling can be over 300 meters long in total and is designed as "star" or "serial".

Pick by Light mounting rail

The BUS system is supplied with 24V and may also be operated without cover. The advantage of the open solution is that it is very easy to convert the system. The displays only have to be moved.

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Pick by Light Displays with Quick-Click

Our displays are connected without cables (via spring contacts) to the BUS system of the mounting rails, whereby each display has a unique MAC address. The controller can use this address to differentiate and control the displays. Mounting is done without tools by simply clicking on the mounting rail (Quick-Click-System).

If necessary, the storekeeper can remove the Pick by Light display from the mounting rail with a simple tool and then click it back in again. With this system, every conversion is child's play.

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Option: Pick by Light Sensor for monitoring access

Pick by Light Sensor
The sensor (upwards) monitors access to the storage compartment and can also automatically acknowledge the removal or release the button for acknowledgement.

The absolute innovation of the Pick by Light displays is the optional integration of sensors. First, the sensors monitor the correct access to the storage compartment. Secondly, they ensure acknowledgement on picking. Third, they can fully automate the acknowledgement process. Depending on where the displays are mounted, the sensors are aligned either upwards or downwards. Almost every display can be equipped with a sensor.

Pick by Light Sensor enables the acknowledgement button.

A list of displays that can optionally be equipped with a sensor can be found here.

Only if the employee has correctly accessed the storage compartment, the button is released for acknowledgement.

A manual confirmation of the removal at the button is therefore not absolutely necessary. However, we recommend a complete automatic acknowledgement only when the quantity = 1. Such picks are often used during sequencing in the Automotive instead.

Counting the number of pieces with a sensor is possible, but only recommended in rare cases. Here the construction of the storage compartments and the articles is decisive. It is imperative that each withdrawal generates only one sensor signal. And this is exactly what is rarely possible in practice.

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Correct planning of Pick by Light

From a technical point of view, one Pick by Light consists of individual BUS systems with a maximum length of up to 500 meters and up to 100 displays. For this reason, certain electrical rules must be observed on each BUS and on each controller. Only then can the entire system function stably and correctly.

When planning larger plants, we calculate the following parameters in particular:

  • Controller performance
  • Resistance of all BUS lines
  • Electrical capacity of the BUS system

The decisive factor is that the entire communication between the individual displays runs without interference. Each display, each cable and each mounting rail has its own electrical capacity, which in total must not exceed a certain value.

When planning our systems, we assume that each display can be controlled simultaneously. Some other suppliers impose a limit on the number of displays that can be switched on at the same time. We do not do that! We have implemented an intelligent control of the power supply units and therefore always have enough power reserves available.

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What happens if the calculated parameters are not correct?

Even an electrical overload of the controllers will then automatically switch off the system. The automatic fuses then blow.

If the capacity of the overall system is too high, the electrical edges of the signals are so flat that the receivers no longer work. As a result, the entire communication is partially or completely disturbed.

The answer to the question is: Then we redesign the cabling and the distribution of the controllers until everything fits. In principle, all this is not difficult, but it is essential to take this into account for every installation. This is exactly why we use a special cable with a low electrical resistance and capacity in our Pick by Light systems.

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What reserves do we need to plan for?

Basically, the question cannot be answered very easily. During the Pick by Light planning phase, we consider the necessary requirements together with the customer. We always take the conversion and expansion plan into account. For some plants the need for reserves is 2-3%, for some however 10-12%. Therefore, we always clarify this question in the course of the discussions during the preparation of the specification sheet.

Important: Consider reserves for expansion and conversion!

For the planning, a layout of the planned plant is normally sufficient for us. The positions of the controllers and the cable routes are then derived precisely from our planning. Based on this, the customer can then prepare his power supply and network connections.

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Pick by Light Assembly made easy

At that time, in the 90′ years, the pick by light assembly was very complex. Each display had its own cable to a small mini-controller in the mounting rail. All mini-controllers were in turn connected to a large controller via a BUS system. The large controllers were then connected to a PC via many serial interfaces. Very, very many cables ...

Today, the installation is quick and easy, so that the costs are also low. Aluminium rails are mounted on shelves or beams. A single 4-wire cable connects the rails to the LAN controller. Thanks to the Quick-Click system, the displays can be mounted on the rails very easily and without any further cabling. Optimum spring contacts ensure a perfect connection between the display and the BUS system.

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Pick by Light yourself?

This question can definitely be answered with a "Yes". How exactly this works and what you need and have to prepare for it is explained in a separate article. Of course, we will also be happy to support you in the planning phase. Read more about this here: Pick by Light - building it yourself.

... and if drilling is not allowed?

No worries. In such cases we deliver the mounting rails with magnets. On the heavy load shelves (SLR) the magnets hold very well. Depending on the length and number of displays, we mount one magnet at a distance of approx. one meter. In this case, the final assembly takes only a few minutes! After the "clack" only the BUS cable with 4 wires has to be connected. It is as simple as that.

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How flexible the Pick by Light installation can be?

Due to the special Quick-Click-System the conversion is very easy. A BUS system is integrated in the aluminium profiles. The indicators are connected via three spring contacts to ensure power and data supply. All you need to remove the displays is a simple tool. No cables and no screws. Then you can easily change the position of the ads. The controller automatically recognizes the displays. For a simple stock transfer within a picking zone, an IT conversion is not even necessary. The display can be easily moved with the goods.

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Add or exchange new Pick by Light ads

Also very simple... A new display is simply clicked into the aluminium profile with a quick click. With a small tool (spatula) the mounted displays can be removed from the profiles very easily. The displays can then be very easily configured via a web interface. If the system is expanded, the new displays log on to the system fully automatically. At the beginning each display has the name of its physical address. Via configuration, the preset designation is adapted to the desired designation (e.g. storage location). The exchange of the displays is also very easy. Only the physical addresses of the replaced displays are exchanged. The rest happens automatically. The assignment to the zones is also configured via the software. Who can replace or configure the displays? Actually anyone who is authorized to use the web-based configuration program. No technicians need to be employed for the conversion or extensions.

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Picking areas

You are in a large shipping warehouse where several areas are to be found. The larger the bearing, the more structures they should recognize. You see different employees picking different orders at the same time.

This is exactly why it is necessary to divide the warehouse into several picking zones. Each zone processes its own partial orders. This is also divided Pick by Light into logical zones. We will deal with the structure of the hardware separately later. First we will deal with the logical division. Then we will think about the hardware.

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How large can a picking zone be?

In principle, the question cannot be answered as simply as this, insofar as no further facts are known. The size of the picking zone depends on many factors, which is why only a thorough analysis can give the correct answer. The most important thing is that the employees keep a very good orientation. Access to the goods should be fast and targeted. The quality of picking must be as high as possible.

The system must be supportive for the employee and not disruptive.

At a semi-automatic picking system with conveyor technology Pick by Light and flow racks, the picking zones are approx. 6-8 m long. The conveyor technology also serves as a buffer, whereby the correct distribution of the goods in the zone is achieved by the A/B/C analysis. It is very important that the employee has a good view of all lights and has the shortest possible walking distances.

For completely manual systems with picking trolleys, the size of the picking zone varies greatly. Sometimes the zones are very long and are even served by several employees at the same time. You'll learn how to do this in a moment ...

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Fast navigation

A single picking zone can also have several hundred displays. Sometimes the picker also has to stand with his back to the pick by light (B or C items). To keep an overview of the storage compartments, special displays are used for quick navigation. At a glance, the picker can see where the active storage compartments are positioned (bottom left, top right, centre or back). Thus, each storage compartment is assigned a segment of the navigation display. After each acknowledgement the Pick by Light control updates the navigation display automatically.

In addition to the graphic display of the active orders, the navigation display shows the number of open withdrawals. Practice shows that the use of navigation makes work much more relaxed and faster for the order picker. This results in a total performance increase of approx. 5-7%. The low cost of the function justifies the investment.

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May several employees work in one picking zone?

Yes! The answer is clear inasmuch as the LUCA-Server is used. With our system several employees can work in one picking zone. We have multicoloured LEDs available on the displays. Each employee and his order is assigned a separate colour. The problem of simultaneous access to the compartments is complex, but we have solved it very well. In the LUCA-Server a special procedure was developed for this purpose for synchronization of the expenses and access to the same subjects.

This procedure enables correct coordination between the individual processes for several employees and orders. Each employee works with his own data. However, each process in the picking zone does not send the telegrams directly Pick by Light, but to a synchronization module. The module is then responsible for the correct coordination of access to the common storage compartments.

Do you want to know exactly how that works? The topic will soon be covered in a separate blog article. Stay tuned...

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Can the picking zones be divided flexibly?

The function is possible, but very complex. The challenge does not only affect the system itself Pick by Light, but also the warehouse management system (WMS) and the control of the conveyor system. Whether the dynamic division of the picking zones is really practicable, we still cannot answer with a clear "Yes". We always examine these requirements very thoroughly and precisely before such systems are built. We have already developed many variants of the solution, but almost every solution was very customer-specific. We will present some examples of this soon in our other blog articles.

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Pick by Light Sequence and the work steps

Do you know of a plant that is exactly the same as the other one? Unfortunately, we don't. Very often the requirements for the Pick by Light are very different. We integrate different solutions in our systems and very often build the processes according to the customer's requirements. Of course, as with any solution, there are comparable sub-processes, but customer requirements predominate in standardisation. The entire logical data processing is handled by the LUCA-Server. Read on and learn more.

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Start of picking

There are already several options when starting picking. But how can the Pick by Light start the correct orders? Can the completeness of the last order also be checked? Here you will be given the answers to the questions. There are basically two different start methods:

  • Start via a document with bar code
  • Paperless picking (FIFO or external trigger)

If the cartons or containers are marked with a barcode (1D or 2D), stationary or mobile scanners can be used for Pick by Light activation. In this case, the activation can also take place via the delivery note or invoice. RFID technology is also supported.

With paperless systems, the orders usually start automatically, either from a data buffer or by automatic ejection of the containers via a conveyor system. In both cases the LUCA-Server the individual processes and ensures the appropriate quality. With some solutions, the start of the next order will only be possible after the previous order has been completely completed. If an error occurs here, the system generates an error message.

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Simultaneous, sequential or pagewise?

If you have already started picking, the displays must actually be lit now. But how are they best lit? All together, one after the other, first one and then the other side of a shelf aisle? With different methods we achieve different goals. As a planner, you need to understand the exact procedure well and choose the correct method, taking cognitive ergonomics into account. This point is very important when designing the systems. Take your time to find an optimal solution.

Although a Pick by Light display is very simple in principle, the sequence can be structured very differently. The control is done by a software module on the LUCA-Server. If necessary, we also use different techniques simultaneously. With the simple systems, all displays in a picking zone light up simultaneously. This is also the standard. In other cases we form a picking route and control the picking sequentially.

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Confirmation of withdrawal and end of order

When all articles have been picked, the employee confirms the picking with the button. The confirmation of the pick triggers a feedback to the higher-level warehouse management system.

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Pick by Light costs

We would be pleased to make you an offer for a Pick by Light system. In a further article we have described different versions of Pick by Light and defined the required information. We would also be pleased to support you in your planning. Please contact us here.

Read on: Pick by Light System

Pick by Light for over 20 years

In 1988 Udo M. was a young logistician for a pharmaceutical company and absolutely had to improve his dispatch warehouse. There were many problems with performance and quality, and the computer technology of the time was already very modern. Paper lists and ballpoint pens were the only aids to picking.

Udo described the problem to his good school friend Rainer. Also some weeks later Rainer K. (young electronic technician from Iserlohn) decided to develop the first "Paperless Order Picking". Udo was very enthusiastic about the idea. A large system with many displays. The displays should signal the picking quantity directly at the storage compartment. No more paper lists and ballpoint pens! "Simple and ingenious!" said Udo.

So the first Pick by Light with more than 2.200 displays was created, but the task for Rainer and his team was not as easy as they had been thought. But it worked. The performance of the system has increased significantly, as the error rate, has fallen to almost zero. Do you want too? ... then you've come to the right place!

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In logistics and production, Pick by Light is one of the best and most widely used picking solutions. The simple assembly and the flexible conversion possibilities make the system very attractive. However, with many storage compartments in large warehouses the price is also high. Therefore it makes sense to use the system for picking A-articles and to support B- and C-articles with other technologies.

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