Friday 28th Oct 2016 - Logistics Manager

Sensors to keep the warehouse moving

More than one thousand Leuze optosensors are used in a new order picking system at Reyher’s high bay warehouse in Hamburg. The high-speed automated system relies on information supplied by the many different optoelectronic sensors to complete the complex operating sequences involved.

They ensure that Reyher, a screw supplier, is able to supply its customers with the requested items at the right time and to the right place.

Reyher’s high-bay warehouse is 108 metres long and 36 metres high. It accommodates some 36,000 pallets over five aisles and has capacity of more than 60,000 items. In developing the modern high-speed order picking system, automation specialist UCS Industrieelektronik specified Leuze sensors to cope with the complexity of the warehouse logistics. One of the reasons was that they could standardise on one brand for so many different applications: identification and tracking, positioning, checking and measuring contours, monitoring compartment occupancy and compartment depths, measuring distances, protecting staff and machinery, and transmitting data using light.

Retro-reflective versions of the sensors with a range up to 12m and the diffuse reflection scanners with ranges of 800mm feature throughout the Reyher order picking system. They are used for detecting containers with widely differing surfaces, whether shiny or bearing a bar code label. And they are not affected by conveyor belt vibration.

One application that the 46 series were deployed on was to determine the number of cartons per pallet, achieved by detecting the number of complete individual layers and allowing the system to compute the total quantity of screw packets per pallet.

The sensors are also used in the transport system, typically for monitoring the flow of pallets, signaling the arrival of a pallet to initiate relevant switch-point changeovers or conveying functions. They also assume positioning functions whereby the first optoelectronic sensor reduces the conveyor speed and a second sensor is used to bring the pallet to a precise standstill.

Since the entire logistics centre is designed for high-speed operations with network connectivity, UCS chose a bar-code scanner with integrated Profibus terminal, the Leuze BCL34. It has a data transmission rate of 12 Mbits/s and is being used for data acquisition flow throughout the entire system. The direct flow of data between the bar code reader and Profibus master ensures that the full capability of the BCL34 can be used by this ultra fast-response logistic system – all transported items are marked with bar codes and are scanned before each decision point and at the various order picking positions.

Other Leuze optical sensors involved movement of goods through the high-bay warehouse are the OMS distance measuring sensors and the DDLS 200 optical data transmission devices. The milli-second operating cycle of the OMS make it ideal for accurate positioning of the rack handling devices.