Posted to News on 10th Dec 2008, 14:27
Intelligent Line Shaft software increases machine throughput
ELAU, Schneider Electric's packaging automation company, says it has updated the principle of electronic line shafting (ELS). The Intelligent Line Shaft (ILS), a new software module complying with IEC 61131-3, is said to be capable of increasing machine cycle rates by up to 30 per cent without any additional programming or mechanical redesign.
ELS has long enabled improvements in packaging machinery performance by replacing a mechanical line shaft with servo axes slaved to either a real or virtual master axis over a network. The introduction of the ILS can, it is claimed, improve machine cycle rates by a further 10 to 30 per cent by limiting velocities and accelerations at critical points, then compensating by increasing speed in non-critical portions of the motion profile.
In ELS, the machine's motion control software transforms the position values for each axis module into cam parameters. The master bases the maximum machine speed on the axis or mechanical component with the highest physical load, or on the motion that will affect packaging quality.
Critical motion and compensation
However, the ILS eliminates the rigid time-constant execution of master/slave motions. During a machine cycle, the master receives feedback from the individual axes and anticipates if an individual axis is about to exceed a set limit value for machine speed and acceleration during the next machine cycle. When the critical motion phase arrives, the ILS-enabled master then reduces the speed and/or acceleration of that axis to avoid exceeding the set limit. Outside the critical motion phases, the virtual master may even increase the speed of the axis to a value significantly above the previous set speed.
Cycle rates can therefore be optimised for speed or for reduced wear. ILS is a software module in ELAU's automation software library and is available to Elau users free of charge. Its integration into programs based on the Elau programming template typically takes an hour. Up to 10 slave axes can be optimised within a machine cycle in terms of both maximum acceleration and speed. The ILS software module is suitable for optimisation of both existing machines and new designs with no additional programming or mechanical redesign.
