In control since 1995

Control Systems Obsolescence: Support Strategies and Key

Considerations

Optimao

A comprehensive survey of the UK’s manufacturing machinery plant and machinery assets will leave us in no doubt that the majority of these were built to last mechanically. Naturally, robust steel frameworks of machines age much more slowly than their moving parts and also have an extremely long life span if well-maintained. However, with those same machines’ control systems the case is different. Modern technology advances so quickly that a system can be out of date in as little as 10-12 years. In this article, Michael Hill, managing director of Optima Control Solutions, looks at three different manifestations of control system obsolescence and offers practical advice on how to deal with each case. The last part of the article contains a checklist of the key factors to consider before moving forward with any obsolescence support strategy.

Type of obsolescence: Support strategy:

1. Parts no longer supported by the OEM; Incompatible with new equipment;

Catalogue the most vulnerable components and plan a step-by-step migration of the control system to up-to-date and openly available control equipment starting with the most critical components first.

2. High frequency of breakdowns/ system failures;

Catalogue the most troublesome components, determine the availability of compatible components and essential product knowledge. If deemed insufficient of either/both replace the control system. For high-dependency systems consider alternative design concepts: e.g. redundant control systems.

3. Equipment will not meet the producers needs to make products that the market wants

New machine or a complete system overhaul within a short period of time.

We consider these in detail below.

1. Control system components no longer built or supported by the original manufacturers. It is now very rare, and has been for some time, for machine builders to use home-grown control equipment in their machine control systems. Virtually every machine builder uses components manufactured by specialist companies. Now, as in most industries, the control and automation industry is measured by its continuous innovation and development record. It is an essential culture that requires significant investment of both time and money on the part of those manufacturers. However, as current components slide into their obsolescence phase and are superseded by new, more advanced products, control equipment manufacturers employ different strategies to handle such obsolescence. New developments demand that those manufacturers steer the market in the direction of using their latest equipment. The last generation equipment becomes another of the “Legacy equipment” listed items.

It is essential that the implications to be drawn when equipment manufacturers label previous generations of their equipment as 'Legacy' are understood. – e.g. one should read: “these components are no longer available” or “have limited support facilities”, “this technology is obsolete” and so on.

Another problem encountered by the control system designer is poor 'backward compatibility'. It is not unusual for equipment makers to upgrade firmware versions in one of their products without fully considering previous generations of that product and in doing so prevent the latest software version from directly interchanging with previous product releases. This will almost certainly mean that time-consuming engineering resource is needed when retro-fitting newer technology.

Another acknowledged consequence of obsolescence is to see dramatically increased the prices of any legacy products - sometimes increasing many times over. It is fair to say that the “Supply and demand” law is “Alive and well”. The relatively high prices for the legacy equipment do however make the latest products commercially more attractive.

Another key consideration for companies that have obsolescence vulnerability on critical plant is the time that it can take to source replacement parts. Internet auction sites are not a viable support strategy but are too often relied upon by under-pressure engineers. Even where large, distributed companies have some legacy stock, it might be expensive, it might be available but it is not unusual be stored in a central location where it is available to a great number of potential users. So when you need it – it might not be there.

With each passing year obsolescence is a phenomenon that plays an increasing role in an engineering support strategy and not only due to the natural aging process of existing hardware technologies. Because component manufacturers want to offer software based functionality and flexibility, that desire, coupled with their low costs, tends manufacturers to use microprocessors more and more, meaning their development cycle and “time-to-market” reduces significantly and subsequently shortens the useful lifetime of the equipment.

It is vital that, regarding obsolescence, an engineer is aware of the status of the control equipment within their scope of responsibility and has a viable strategy to deal with the catastrophic component failure of a vulnerable product. A control system integrator is a great source of help and advice – it is worth knowing that industrial automation manufacturers tend to communicate with their solution partners early when highlighting the “soon-to-be-obsolete” products. So either talk to the equipment manufacturers or to your system integrator about your susceptibility to obsolescence.

2. Frequent breakdowns and system failures

We are (I am) happy to say that there is a newfound tendency towards engineers employing empirical data in the analysis of machine reliability these days. The “Trusted Gut-Feel” is actually no longer actually trusted. Obviously machines fail for numerous reasons, but it is common knowledge that the frequency of failures increases with age.

In a control system, it is difficult to see a component degrading with age. Very often it is only when a catastrophic failure of a component occurs that we become aware that there is a problem. It is well understood that electronic components have a limited lifespan, the absolute lifetime of a component is determined by the number of hours-per-day that it operates and how close to its designed upper rating it runs. It is fair to state the “Inevitability” that a machine control system will fail at some stage and naturally it will fail more regularly towards the end of its useful lifetime. Good management of legacy control systems, though always very prudent, becomes more essential in those latter stages as independent spares and support become sparse. Here are some essentials when managing near obsolete plant:

1. Maintain good copies of circuit schematic diagrams

2. Maintain reliable backups of any functional software that is resident in the control system

3. Catalogue some key calibration values for equipment that is performing well.

4. Identify vulnerable items that are either close to or in fact are obsolete. Score them for criticality and availability

5. Correspond regularly with control equipment manufacturers and system integrators to stay abreast of ageing products projected availability

Making the decision to upgrade a control system is not trivial. The point in time where there is no option but to upgrade is often once significant costs have been incurred in lost production and uneconomic repairs have been carried due to equipment failures. Appreciation of the vulnerability of any particular control system varies according to professional discipline. Engineers generally flag potential issues early, whilst financial management often do so much later, considering the risk versus cost arguments from differing perspectives. However, delaying too long will become a serious and expensive problem for both parties.

3. The system no longer provides an adequate solution to the manufacturer

It is not only the equipment owned by manufacturers that suffers obsolescence. The goods that those companies manufacture also need to be constantly developed to maintain or grow their own market share. New machinery is an obvious choice when targeting new product manufacture but it is quite normal for manufacturers to employ their existing, older machines and adapt where possible to produce these newer modern products for their own markets. This solution can have some obvious limitations, but careful analysis of the plant can often resolve its capability questions and determine with some certainty the plant’s ability to produce the required goods. Indeed, machines can be improved to such a level that these will be able to produce future generations of product by employing latest control technology and techniques. It is important to understand that a machine’s mechanical systems also have a critical part to play in determining the possibility of its adaptation. Careful consideration though can often identify a much cheaper route to improving product specifications and choices.

The checklist to defining an obsolescence support strategy i. Risks associated with a machine failure

What are the financial costs of machine downtime? A simple financial risk assessment would allow you to prioritise some control system upgrade projects over others.

ii. Maintenance Costs Once the cost of managing obsolescence on a machine outweigh the cost of its upgrade it is time to re-engineer the control system

iii. Return on Investment The cost of a control system upgrade can be significant. It is important to project the return on investment and to monitor its performance following the upgrade.

iv. Constraints and Planning Factors that often limit the opportunity to upgrade include limited downtime windows or perhaps strict procurement policies that limit spares holding and subsequently compromise the ability to plan effectively for potential obsolescence problems. ”Planning for the worst scenarios” should be considered to allow for a quick response in case of system failures.

v. Available Resources – Identifying specific budget and allocating it to addressing obsolescence problems is a smart thing to do. By costing your chosen strategy and setting aside an amount of money in each period (monthly, quarterly, annually) your selected strategy can be managed and implemented.

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Disclaimer: All data provided in this report is for informational purposes only. Opinions expressed in this report are those of the relevant contributors. Reproduction and citations are allowed after appropriate referencing of the full report. Optima Control Solutions Ltd. reserves the right to prohibit the use of this report by third-party websites and third-party publications. Images sourced from: Optima™ gallery – all copyrights reserved. Design: Picasa, Gimp Written by: Hristina Stefanova Revised by: Michael Hill