Order picking system boasts a thousand optosensors

More than one thousand Leuze optosensors are vital to the smooth running of an extensive new order picking system at Reyher's high bay warehouse in the heart of Hamburg.

More than one thousand Leuze optosensors are vital to the smooth running of an extensive new order picking system at Reyher's high bay warehouse in the heart of 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 major 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, 108 metres long and 36 metres in height, accommodates some 36,000 pallets over five aisles and has capacity in excess of 60,000 items.

In developing the modern high-speed order picking system, automation specialists UCS Industrieelektronik of Germany specified Leuze sensors to cope with the complexity of the warehouse logistics.

One of the key 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.

Design features of the 46 Series include a choice of connection variants - M12 connector integrated directly in the durable plastic housing or a cable outlet with an attached M12 plug - this was another important factor influencing the choice of the Leuze sensors.

Add to that an innovative fastening concept for integrating both sensors and reflectors into a system, irrespective of whether its pole or wall mounting, the systems installation team had a real winner; adding these sensors into the overall scheme was much easier, simpler and less time consuming.

Retroreflective versions 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 reliably 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, signalling 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.

During installation, the 46 Series sensor can be mounted between the individual rollers of a conveyor with the lens facing upwards.

In this mounting position, the outstanding insensitivity to dirt accumulation pays dividends.

The 46 Series features a generously dimensioned lens surface, ensuring that the light scanner remains functional even with an increasing accumulation of dust.

Any disturbing machine contours are blanked out by a highly efficient background suppression system.

Irrespective of whether these sensors are installed between the rollers or at the side, what counts when it comes to successful positioning is their outstanding capacity for reliable switching precision.

This guarantees that conveyed items are positioned and transported without skewing or tilting, for example during transfer from a roller to a chain conveyor.

Any imprecision would result not only in material damage but also the substantial costs involved in re-positioning the item.

Since the entire logistics centre is designed for high-speed operations with network connectivity, UCS insisted on the use of the world's first barcode scanner with integrated Profibus terminal, the Leuze BCL34.

It has a data transmission rate of 12Mbit/s and is being used for data acquisition flow throughout the entire system.

The direct flow of data between the barcode 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.

The BCL34 brought to the Reyher warehouse high speed communication, simple parameterisation via the Profibus master and an extremely close reading distance.

Other key Leuze optical sensors that are central to the efficient movement of goods through the high-bay warehouse are the OMS distance measuring sensors and the DDLS 200 optical data transmission devices.

The millimetre precision and millisecond operating cycle of the OMS make it ideal for accurate positioning of the rack handling devices.

Data communication between the position regulator or control system and the OMS 2 is implemented using all commonly used networks such as Profibus, SSI, Interbus, DeviceNet, CANopen and others.

To ensure optimum benefit from the high-speed rack handling devices, not only does the position have to be determined with the precision of the OMS 2, but data transmission between the main frame computer and the rack handling device has to comply with stringent standards.

With its low susceptibility to interference, no-contact, wear-free data transmission using light has proven highly successful in this context, the Leuze DDLS 200 was deployed.

It can transmit data over distances as great as 300m at high baud rates up to 2Mbit/s and is designed for simple integration into any network architecture - Profibus, Interbus S, Rockwell Automation DH+ and RIO or also Ethernet, CANopen and DeviceNet.

The Reyher high bay warehouse is a fine example of how optical sensors that are available from Leuze Mayser in the UK have been brought together to create monitoring, detection, signalling measurement and data transmission without any physical contact between sensor and packaging.

This enhances the reliability and precision while reducing operational running costs.

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