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 U.C.S. Industrieelektronik of Germany specified Leuze
sensors to cope with the complexity of the warehouse logistics. One of the key
reasons was that they could standardize 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.
Retro-reflective 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, 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.
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, U.C.S. insisted on the use of the world's first 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
utilized 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
parameterization 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 milli-metre precision and milli-second 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 2
Mbit/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 Electronic in the UK have been brought together to create
monitoring, detection, signaling measurement and data transmission without any
physical contact between sensor and packaging. This enhances the reliability
and precision whilst reducing operational running costs.