Customer application 1 April 2022
Lighting Management for Greater Comfort and Efficiency

In large logistics centers, goods need to be sorted perfectly and stored in a very limited space. For fast order processing without errors, optimal illumination is important in warehouse systems. Because lighting accounts for one of the largest energy consumers in these buildings, an intelligent lighting management system with a professional design is essential. It all comes down to energy-efficient concepts, sophisticated automation programs and reliable hardware.

Fashion and lifestyle products, vehicle and machine replacement parts, electrical components: Large logistics centers contain so-called pick towers for storage of a variety of items of different shapes and sizes with maximum space utilization. These multi-level rack systems are traversable, enable a safe and flexible separation of goods and offer up to 3,500 shelves on multiple levels in a compact structure. Obviously, the lighting conditions need to be optimal.

An Overview of the Project

With intelligent lighting management, our customer KEC-Kretschmer Energie-Consulting ensures reliable and efficient lighting of shelving systems in logistics centers.
KEC relies on the fieldbus-independent WAGO I/O System for the necessary flexibility in connecting and controlling its lights and LED modules.
Finding solutions together: KEC especially appreciates the assistance of WAGO Sales and Application Support.

An Energy Pioneer with an Inventive Spirit

For environmental and economic reasons, these rack systems should not be fully illuminated around the clock. Even with LED lighting, the energy consumption would be enormous – an irresponsible approach, both in terms of costs and environmental effects. Therefore, efficient, high-quality lights and intelligent lighting management are necessary in order to ensure both an optimal working environment and highly efficient energy use.

Dipl.-Phys. Roland Kretschmer, CEO of KEC-Kretschmer Energie-Consulting GmbH, has spent more than 30 years working on these and other energy issues. KEC is one of the leading German companies for shelving rack lighting. “The primary goal of our projects is easy to explain: Whenever and wherever light is needed, it has to be bright enough and offer a good color palette and minimal glare. When it’s not needed, the light should be turned off, or dimmed significantly, in order to conserve the most electricity. It’s really pretty obvious,” he says, summarizing his mission.

Lighting is a Power Hog

For this to actually work, requires a lot of experience, an innovative spirit and reliable technology. “By far the largest proportion of the electricity in such shelving systems is used for lighting – followed by conveyor systems,” explains Kretschmer. “Even before we started using LED technology, we were already working on how to use light most efficiently. That’s why we developed specialized lenses many years ago, in order to achieve optimal efficiency and help our customers reduce their electricity costs.” Proprietary lenses, tailored to specific applications, remain an important component in KEC’s project business; however, they are only one tool among many for achieving maximum workplace comfort with minimal energy use.

Optimal Light Output is the Sum of Many Details

“Pick towers pose special challenges for lighting: 1.20 m wide aisles on four to five levels add up to countless kilometers of transport routes. For optimal illumination in large projects like this, we use 20,000 to 30,000 light points, all of which require demand-driven control,” explains Kretschmer. That is achieved through presence detectors and control of the specific light points. The efficiency chain begins with the presence sensors, explains the physicist: “An aisle needs be safely illuminated as soon as an employee enters it, but not when someone’s just passing by it. Therefore, we developed detectors with specialized infrared lenses to monitor a precisely defined zone with a high level of sensitivity.”

KEC has a comprehensive selection of lenses; every presence sensor can be equipped with one of about a dozen specialty lenses. This customization of the infrared lenses allows two detectors, one at each end, to accurately monitor up to 25 m of rack aisle.

The detector signals are passed to a controller, where they are processed and output to the lights’ control gear in the form of DALI signals. The Digital Adressable Lighting Interface is an international standard protocol used in building automation for lighting control systems. Each DALI device can be identified and individually controlled on the basis of a unique DALI short address. The protocol, defined in IEC Standard 62386, allows for bidirectional data flow, so the control device can also return status messages to the DALI controller.

A Flexible System – Intelligent Control

“We plan our projects individually on the basis of our own lights and LED modules. We rely on the WAGO I/O System 750 for the necessary flexibility in connecting and controlling our lights,” explains Kretschmer. Nils Roth, a technical sales representative at WAGO, adds: “Our controller components are part of our comprehensive fieldbus-independent system. This allows KEC to focus on the actual project and the on-site solution for the customer – regardless of which controllers and connections the end customer’s building control systems already contain.” Each of these peripheral devices can accommodate multiple DALI Multi-Master Modules, which in turn can be connected to up to 64 DALI actuators. Kretschmer is very satisfied with the components’ reliability and compact design: “With the right WAGO power supplies, we can house all the hardware for controlling more than 700 control devices for up to 2,000 light points within a standard control cabinet. The result is a robust system that meets industry standards and requires no additional air-conditioning.”

Kretschmer wrote the automation programs needed for lighting management on the basis of the CODESYS automation software that WAGO supports. It includes the intelligence necessary to ensure optimal lighting conditions in pick towers with the lowest possible energy consumption. ”During the development of the program, WAGO’s Sales and Application Support were extremely helpful,” says the CEO of KEC. “Besides the reliable hardware, that was another reason we choose WAGO: We have a direct contact person who’s always there for us. Whether we’re working through tricky challenges or dealing with high time pressure – we always get professional support.”

The sophisticated lighting controls are oriented fully toward workplace optimization for employees in the pick towers. Each level is controlled separately and has its own dimming values. As soon as a sensor detects an employee’s presence, the area is fully illuminated. Following a certain amount of time without movement, the illumination level is cut in half for several seconds before switching off. If there are still employees in the aisle, they can reactivate the presence sensor by moving again.

In addition to monitoring of individual rack corridors, an additional algorithm ensures further savings by analyzing cluster activity in the movement sensors across larger areas. For example, if infrequently ordered items are stored on the upper levels, or certain areas are unused, with the result these areas are unoccupied for long periods, then the illumination levels can be lowered accordingly, even along transport routes, and not returned to normal levels until activity resumes.

“We incorporated the experience we’ve gathered over the years into the programming,” reports Kretschmer. “Even when there are standard programs like ’night’ or ’everything on’ – for inventory or cleaning, for instance – our customers use the automated mode almost exclusively. Through the control program, we ensure that employees have optimal lighting conditions for as long as they need them.” In some projects, the WAGO I/O System 750 is linked to a higher-level building control system. This allows centralized visualization and operation of the entire lighting control system – in parallel with WAGO Touch Panels 600 on site.

Customer application 1 April 2022 Lighting Management for Greater Comfort and Efficiency