Small controllers push shopping cart production

In 1937 Sylvan Goldman invented an early version of the shopping cart, called a “folding basket carrier,” which had a pair of large wire baskets attached to tubular metal arms with four wheels. In 1950 Rudolf Wanzl patented the stackable shopping cart as we use it today (see Figure 1). The inventor founded Wanzl GmbH, which is currently the world’s largest producer of shopping carts, with 40 percent market share in China and 80 percent in Germany. Wanzl also produces similar equipment for airports, hospitals, and warehouses. Most of these products are made from welded steel wire nettings of different sizes and geometries.

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Figure 1: Manufacturing Wanzl’s shopping carts and other products requires electronic control systems to manage the welding equipment used for connecting the steel wire nettings.
(Click graphic to zoom by 1.9x)

High-quality welding machines have a long lifespan. The welding process does not change over time; however, the control electronics need to become faster, more flexible, and more precise. Wanzl is replacing older electronic control systems on its welding equipment with modern Speedway-767 small form factor modules from WAGO. These modules are positioned directly on the large machines, which they control in a decentralized setup, and are linked together and to upper-layer controllers using industrial Ethernet or fieldbus (see Figure 2).

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Figure 2: The Speedway-767 small form factor controller module from WAGO provides uplink communication via Ethernet or fieldbus.
(Click graphic to zoom)

The Speedway-767 system family includes master modules (75 mm x 117 mm) for uplink communication and up to 64 I/O modules (50 mm x 117 mm) per master module for connection to sensors and actors. All modules are linked via a serial cable bus. Because of the distance between the modules (up to 500 m total), a backplane bus cannot be used. Mechanical mounting on a C-Clamp (DIN-rail) is optional.

Flexible electronic control is needed to precisely weld different diameter steel wires into nets of different geometries. Wires are held in position by magnets until welded. The distributed processor and I/O modules are linked via the serial bus for reliable operation in an electromagnetically polluted environment. Measuring 25 mm or more in height, the individually enclosed SFF boards are ingress-protected according to IP67 (akin to NEMA 6.6P), ensuring protection against dust and water. The fanless system has an operating temperature range from -25 °C to +65 °C. Uplink communication is provided via industrial Ethernet (EtherNet/IP, PROFINET, SERCOS III) or fieldbus (CANopen, MODBUS, PROFIBUS). The software tool WAGOframe is used to set parameters according to standardized Field Device Type/Device Type Manager (FDT/DTM) procedures. A CoDeSys software package based on the IEC 61131-3 standard is supplied with Speedway-767 systems.

Industrial technology events

WAGO exhibited its products at two recent events in Germany. MOTEK, an international trade fair for assembly line and production handling automation equipment, was held September 13-16 in Stuttgart. Colocated with MICROSYS, a nanotechnology trade show, and BONDexpo, an industrial bonding technology trade show, MOTEK covered topics including mechatronics, education and research, and medical equipment assembly. More than 1,000 companies from 23 countries presented their products to more than 31,000 experts from 82 countries.

InnoTrans, one of the world’s most prominent trade fairs for railway technology, was held September 21-24 in Berlin. More than 106,000 visitors from 110 countries, not including the general public during the weekend opening after the fair, had the opportunity to preview 2,400 exhibitors’ products, some of which were based on small form factor modules designed for control electronics.

For more information, contact Hermann at hstrass@opensystemsmedia.com.