Packaging Machine

Networked drives Distributed intelligent drives for a packaging machine: Control networks do not make traditional drive technology obsolete. Although networkable drives offer significant advantages, there are some drawbacks. The key limitations are somewhat slower response times, and less control over multi-axis synchronisation, because commands must travel over a network. From Baldor's experience in implementing systems, networked motion control tends to score very highly in any situation involving loosely coupled axes, as are often found in printing and packaging machines, or materials handling systems, for example. They do less well, and can be unsuitable, where axes must be very tightly synchronised and interpolated as in some sectors of the machine tool industry.

They can be used to distribute I/O. They can also be used to control drives using the more powerful peer to peer architecture. A Baldor customer replaced a centralised motion controller and drives system on a large packaging machine. The use of intelligent drives cut the cabling needed to interconnect the conveyor feeding, synchronisation and carton erection stations to just power and network - a much more manageable arrangement than the previous power and drive cabling which necessitated clumsy drag-chains. The complexity of the central controller itself was greatly reduced, now requiring just a small processor capable of co-ordinating the movement. By using CAN, the manufacturer was able to move from a proprietary network to an industry-standard one (CAN - available in chip form from several leading semiconductor manufacturers), saving considerable expense and software development time, and greatly improving the robustness and reliability of the network.

The peer to peer nature of the motion architecture is also simplifying the company's plans to make their machines more modular, allowing them to create autonomous standalone elements (feeding and registration stations etc) which may be integrated into systems and assigned to work in groups easily, to configure the machine to work with different packaging materials and sizes, or create application-specific machines without the requirement for complex new software programs. In this case, for the eight axes involved, a distributed architecture saved around GBP1500 in motion controller hardware costs alone. As many packaging machines can often have 30 axes or more - the potential for direct hardware savings by using this approach can easily be GBP 5k per machine.

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