Busy bottling companies with plants in Italy and Spain rely on Vacon AC drives which operate turning shuttles and stacker cranes manufactured by System Logistics.
Based in Modena, Italy, close to the Ferrari factory, System Logistics designs and manufactures complete systems and tailor-made solutions for the management of goods logistics within production and distribution systems.
In 2005, System Logistics went through the process of reviewing several drives suppliers in order to revise their technical solutions for stacker cranes and shuttle vehicles - unmanned vehicles that move pallets and palletised containers in a warehouse. Initially the logistics company evaluated 15 drive manufacturers on the basis of a demanding requirement specification. Vacon and four competitors passed the first selection round and were submitted to precise load tests at the laboratory of a motor manufacturer.
"We could say 'yes' to most requirements, and for some that we could not meet, we offered high quality alternatives that the customer accepted. The customer rewarded our endurance by allowing us to reach end-users such as the Coca-Cola Company!" says Marco Beltrami, sales and marketing director, Vacon Italy.
Dedicated customer application
Stacker cranes move in horizontal (X-axis), vertical (Y-axis) and transverse directions (Z-axis) to pick up pallets from a loading bay and store them on shelves. The entire operation is networked and controlled from a central dispatching system. Shuttles, in turn, move along a straight or curved monorail to transport transfer pallets. Accurate positioning of the stacker cranes and turning shuttles is vital to avoid downtime, delays and material damage.
All Vacon drives are equipped with the same application software, custom-designed to optimise ease of use and commissioning. "The stacker cranes employ a regenerative DC bus design (inverter unit + active front-end). The choice of the regenerative solution was supported by a precise energy saving analysis," says Beltrami.
Customers of System Logistics include bottling companies such as Acqua Minerale San Benedetto SpA with plants near Venice, Italy, and Coca-Cola Company with plants in Seville, Spain. Hundreds of Vacon drives operate several dozen System Logistics' stacker crane systems.
Wireless communication
In a busy 500 000 m³ warehouse, a stacker crane is almost constantly on the move. Integration of the drives in the wireless LAN and using the Vacon NCDrive commissioning and maintenance tool simplified commissioning.
Numeric controller
All stacker crane drives are controlled from a single numeric controller designed by System Logistics. This device takes care of position control. The interface is based on the CANopen fieldbus.
Special application logic has been developed in Vacon drives for dynamic load sharing of drives in horizontal movement (X-axis). This optimises the wheel to rail friction and prevents slipping. The stacker crane may reach heights of more than 30 metres and achieve horizontal speeds in excess of 5 m/s while positioning the goods to a fraction of a millimetre. This makes the resolution and bandwidth of the speed and position control critical.
PLC-based position control
Vacon also supplied drives for shuttle vehicles with PLC-based position control. Each shuttle is moved along the rail by one wheel. The main drive is an open-loop Vacon NXL.
Here again, customised software and effective training enabled an easy start-up. The use of the Vacon NCDrive tool with virtual serial communication over a Wi-Fi gateway simplified the testing and commissioning of the shuttle drives.
For more information contact Rob Hare, CHI Control Components, +27 (0)11 824 7400, [email protected], www.chi.co.za
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