Drive simplifies pharmaceutical packaging machines

One of the first controls suppliers to bring the function "building blocks" of IEC61131-3 to the public domain is Elau with its PacDrive automation solution.

The requirement to ensure compliance of pharmaceutical packaging machinery is all to often an open ended, unpredictable process that can account for anywhere between 10 to 40% of a project's total cost.

There are, however, solutions to manage these costs and still meet compliance requirements effectively.

These are a combination of the latest 3rd generation machinery design and user driven standardised function blocks for motion that have simplified the validation of machine control solutions to meet FDA standards.

Generation 3 machinery is designed from first principles for integrated, electronic control using servos, and employs open systems architecture based on internationally accepted hardware and software standards.

This new generation is the most advanced yet, outperforming previous servo and all-mechanical designs on all fronts - speed, accuracy, reliability, flexibility, functionality and cost of ownership.

These advantages are not bought at a price because, while Generation 3 machines require a different set of skills to validate and support than mechanical and previous Gen2 machines, they accommodate product line changes seamlessly, at much greater speed and are extremely easy to reconfigure.

The key to this improved operation is that machine operators can make process changeover adjustments reliably, simply by selecting digital control system "recipes".

This can reduce setup times and improve consistency over manual adjustments that require highly trained technicians.

The capability of the Gen3 control system to provide remote adjustment may also reduce stoppages in sterile packaging operations that create a septic environment and require resanitisation.

In addition to reductions in machine setup times, the totally integrated, high level servo operation provided on Gen3 machines means that exposed systems of jackshafts, gears, pulleys, chains, clutches, and other related components are eliminated.

This provides several benefits for the machine user: more reliable machine operation, lower maintenance costs and a machine that is generally easier to clean.

The latter is the result of an overall more compact machine design that offers fewer areas for dirt and debris to accumulate, leading to possible contamination of the packaging process.

Gen3 packaging machinery also provides benefits to users in that the logic and motion controllers used are not separate hardware platforms with their own and often proprietary languages.

Instead, motion and logic are performed in one control, on the same processor, in the same application program.

This reduction of hardware and software interfaces inherently increases performance, and it also reduces the number of control systems to validate from two to one.

The key to this level of control is the IEC61131-3 programming language standard, which has emerged as an effective alternative to proprietary motion languages.

By embedding motion functions into powerful lEC standard software objects called function blocks, complex servo motion can be performed within a familiar ladder logic program.

One of the first controls suppliers to bring the function "building blocks" of IEC61131-3 to the public domain is Elau with its PacDrive automation solution.

PacDrive, available in the UK through Elau systems integrator, Inmoco, is based on international standards such as IEC61131-3, Sercos, Ethernet and Profibus.

As a result, control systems engineers no longer need to specify a vendor "standard".

They can now write specifications based solely on standards and performance requirements and never have to support another proprietary language or interface.

With PacDrive all five IEC languages - SFC, FBD, LD, IL and ST - are available for user programs.

This means that the user can program motion and logic control in one integrated program, in one software development environment, to run on a single, high speed Pentium processor.

It has been calculated that the seamlessly integrated software and hardware solution provided by PacDriveTcuts machine development times by up to 50% and whole machine life cycle costs by up to 30%, while, at the same time, increasing productivity by an average of 25%.

The process of validating Gen3 machines is also streamlined with the use of software libraries consisting of pretested IEC61131-3 and PLCopen-compliant function blocks.

A recent development is the PackML state model.

A guideline developed by the OMAC (Open, Modular Architecture Controls) Packaging Workgroup (www.omac.org) in the USA, this state model standardises naming conventions for machine states and transitions.

It expedites the validation and documentation workload by addressing the fact that every machine has its own state model regarding how it will start, stop and run.

When the same terminology is used across machines, it becomes much easier to co-ordinate machinery and to extract meaningful performance and MES data from packaging lines.

PackML tag names can readily be mapped to the machine' s existing state model, and the state model can be easily programmed and visualised in the IEC Sequential Function Chart language as a best practice.

In addition to its primary function, PackML (www.packml.org) has also proven effective for visualising and documenting specifications, and for conducting factory acceptance tests.

Its success in these areas is based upon the fact that graphically enhanced specifications are less readily misinterpreted than text-only.

It has been calculated that, as a spec-writing tool, PackML can avoid corrections valued at 5% of a machine's total acquisition cost.

This is a powerful argument for machine builders to embrace the universal state model, because it is OEMs that typically incur the costs of corrections.

PackML is also useful when machinery is reconfigured, as the state model will be instantly understandable and readily modified regardless of the equipment's age or origins.

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