ELAU, Schneider Electric’s packaging automation specialist, has updated the principle of electronic line shafting. The Intelligent Line Shaft, a new IEC 61131-3-conforming software module, can increase machine cycle rates by up to 30% without any additional programming or mechanical redesign. This innovation has already been nominated for the Automation Award 2008 by a jury of representatives from e.g. VDMA and ZVEI.
Electronic line shafting (ELS) has long enabled 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 Intelligent Line Shaft (ILS) can further increase machine cycle rates by 10 to 30% by limiting velocities and accelerations at critical points, then effectively ‘making up the time’ by increasing speed in non-critical portions of the motion profile.
In electronic line shafting, the machine’s motion control software transforms the position values for each axis module into cam parameters. The master bases the maximum machine speed based on the axis or mechanical component with the highest physical load or on the motion that will affect packaging quality.
The Intelligent Line Shaft - 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 will then reduce that axis’ speed and/or acceleration to avoid exceeding the set limit. Outside the critical motion phases, the virtual master may even increase the axis’ speed to a value significantly above the previous set speed.
The cycle rate can therefore be optimised for maximum speed or reduced wear-and-tear. ILS is an IEC 61131-3 conforming software module in ELAU’s automation software library and available to ELAU users free of charge. Its integration into programs based on the ELAU programming template typically takes an hour. Up to ten 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 minimum effort, without any additional programming or mechanical redesign.