EtherCAT optimises horizontal conveyor system

While developing its new tna roflo 3 horizontal conveyor, tna Australia, a manufacturer of food packaging systems, chose to use a Beckhoff controller to boost system power while streamlining the architecture. The feeding and distribution system can be integrated seamlessly into a packaging line for food products and impresses end users with its high flexibility and speed of operation.

tna Australia is one of the world’s leading manufacturers of turnkey, integrated packaging and processing solutions for the food industry. The tna horizontal and vibrating conveyors distribute and transport products such as snacks, confections, nuts, pasta, fresh produce or pet foods and feed them to the packaging system. The most recently developed horizontal conveyor system, the tna roflo 3, is an innovative solution for the transport and distribution of food products.

“It was specially developed with a view toward simple integration in upstream or downstream seasoning, weighing and packaging modules, and enables the development of customer-specific solutions. With the tna roflo 3, different products can be conveyed at the same time on a single line and moved in different directions,” explained Kerryn Ball of tna Packaging Systems.

Perfect control using EtherCAT communication

The tna roflo 3 horizontal conveyor gives the operator complete control over the speed and direction of movement of the conveyed food products by implementing control commands virtually in real time. With a view to performance optimisation, tna’s aim in developing the tna roflo 3 was to implement a distributed control system with real-time ethernet as the basis for communication. “Prior to the start tna had considered a range of communication options. Ultimately EtherCAT was the only system that is proven to work efficiently on standard hardware without having to install a processor board especially for the communication,” Ball stressed.

“Since EtherCAT is an open standard protocol, we were able to develop our own EtherCAT master for real-time communication with the horizontal distribution system. The openness of the EtherCAT platform also gives us the option to use devices from different vendors. That offers both us and our customers valuable flexibility,” Ball said.

Simplified cabling, lean control structure

tna has now installed EtherCAT into all non-standalone tna roflo 3 systems worldwide. Currently, the most extensive system of this type is located in France: 21 servo axes for three production lines are controlled by just one computer. There are further large-scale installations in Korea, with 18 axes, and in Mexico, with 19 axes. A single communication network can be used for several tna roflo 3 systems.

The connection to the field level takes place via the EK1100 EtherCAT Coupler. Digital inputs such as level sensors and all universal inputs are connected via standard input terminals. Air-operated doors, warning lamps etc are connected to the digital output terminals. The EK1122 branch terminals increase the topology options of the EtherCAT network in the case of larger systems for which a star topology is suitable.

Highlights of the EtherCAT solution

In the example of the system installed in France, 21 tna roflo modules make up a distribution system that is perfectly tailored to the needs of the customer’s application. A single tna ‘switcheroo’ or ‘lifteroo’ feed line — a mechanism that separates, tilts and turns the tna roflo pans — is able to distribute three different products from the processing line to the waiting packaging machines. This innovative function changes the way in which processing lines are interconnected and enables the simultaneous movement of products in several directions on a single packaging line.

“Previously we needed three conventional feed lines for this — with the corresponding costs and space requirements. With the EtherCAT-based controller, the 21 servo axes distributed throughout the entire factory are controlled by just one powerful computer,” said Ball, outlining the advantages. “Thanks to EtherCAT we can build and test the tna roflo modules at our production site. All cables are located in the roflo modules; in addition, information is exchanged over the network so that no ‘spaghetti cabling’ is created and the system can be designed very simply,” Ball explained.