Leuze electronic sensors are being used to ensure the reliability, safety and efficiency of a new € 130m distribution centre for the German chemist chain, dm-drogerie markt, based in Cologne.

With over 2,400 stores, 36,000 employees and sales of € 5.6Bn, the chain requires exceptional material handling and turned to Swisslog AG to complete the distribution system upgrade which expanded dm-drogerie markt’s capacity.

The upgrade involved creating one of the most modern logistics centres in Europe, covering a total of 50,000 square metres. The order picking warehouse for pallets and small parts and the high-bay warehouse comprised 18,000 pallet spaces, 5,000 order-picking spaces, 13 high-bay storage devices and some 3,500m of pallet conveyor technology for a warehousing capacity of 390 pallets per hour.

Other statistics are that there are 140,000 storage locations in the small-parts area in which 52 high-bay storage devices are used to warehouse, supply items in the order-picking zones and retrieve the order containers used here. A key component of the facility is the CaddyPick system from Swisslog, which is a semi-automatic order-picking system with a total length of more than 2,000m and a total of 163 controlled telpher-line vehicles.

In such a complex system with such a high level of automation, considerable reliance is placed upon the sensors and Swisslog worked with Leuze electronic in this regard.

Barcode readers and barcode positioning systems as well as optical data transmission systems are all key components supplied by Leuze in the distribution centre. Additionally operator safety is provided by Leuze’s COMPACTplus safety light curtains with integrated muting to satisfy the high requirements for safety, process efficiency and reliability.

Fast ID for directional decisions

For the order picking of small parts, approximately 700 barcode readers perform reliable and fast product identification. Leuze’s BCL 34 and BCL 504 barcode scanners are used with their fully integrated Profibus providing fast data communication which in turn provide the maximum reading capacity with delay-free data passage. The Leuze units provide full Profibus integration rather than just the communication protocol conversion offered by some competitors, which means the units can be configured remotely by the control system.

Leuze’s BCL 34 barcode scanners are used for product identification, in part because their short minimum reading distances and small size enables their use in constrained spaces.

BCL 504 barcode scanners are used to identify packages and on pallet transportation systems because of their reading field of 200 to 2,400mm, their large depth of field and compact construction. dm also benefits from the high reading reliability provided by the code reconstruction technology built into all BCL500is.

Leuze electronic’s code reconstruction technology, used across the UK in supermarket and catalogue shopping distribution centres, works by scanning across a barcode at an angle, rather than along the central axis. Many scans are taken across the barcode and the BCL500i reconstructs these numerous slices into one complete barcode. This enables the scanner to overcome gaps in the barcode, typically be due to poor print quality or soiling of the label.

Vehicles with barcode readers

Barcode technology is also used for the positioning of high-bay storage devices and the CaddyPick telpher-line vehicles. Here, the Leuze BPS 34 positioning systems are used, consisting of two, easy-to-handle components: the read head and the barcode tape.

With a high level of functional reliability and minimal maintenance, these systems are predestined for use in the complex distribution centre. The BPS system works using a laser scanning the barcode position information with a reproducibility of ±1mm and the calculated position values being are passed on in 2ms intervals.

Optical data transmission

In the high-bay storage area, position data is transmitted with Leuze’s DDLS 200 optical data transmission units. These devices permit contact-free and wear-free optical communication without interference, at a transmission rate of up to 2 Mbit/s over distances of up to 500m.

Safety has priority

However important efficiency, the safety of workers in the distribution centre is a top priority and Leuze’s COMPACTplus safety light curtains are therefore relied upon. These curtains are type 4 protective devices to IEC/EN 61496. Their integrated muting function helps provide permanent personnel protection within the system without interfering with the flow of goods.

A groundbreaking solution

Leuze electronic, provides many different types of sensors for the numerous systems in the new distribution centre, from the simple switching sensor to high-end solutions for barcode identification of pallets and boxes. By using scanners for the precise positioning of high-bay storage devices and order-picking telpher lines, as well as systems for wireless data transmission, Swisslog has created a logistics solution which, with regard to efficiency, is said to break new ground in Europe.