Industrial Control Systems Between Innovation and Stability - Between Modernisation and Eternal Maintenance
Production plants are often in use for decades, but their control systems have shorter innovation cycles and/or their availability is restricted. This means that a number of plants are currently being used with outdated control systems or visualization and control technology whose maintenance and spare parts have been officially discontinued. If a malfunction occurs, it can result in anything from prolonged downtime to total failure of the plant.
Walter Woiset schläger
director of SOFTwerk prof.
automation GmbH
Austria
“Production plants simply have to work” – but for how long? “What can be done?”
- A completely new system?
- Gradual changeover?
- Re-use parts?
- Economic efficiency?
Appropriate Individual Consultation Is Essential
Control systems are subject to rapid development which ensures that there are always advantages, particularly in the field of information technology. Such advantages could be improved through operating/observational capabilities, continuous data concepts, global communication possibilities for remote maintenance and diagnostics, as well as connection to superordinate computing systems. Modernization costs often pay for themselves by increasing or optimizing production, reducing downtime and minimizing costs for maintenance and spare parts.
Failing that, a partial modernization is cheaper than a comprehensive spare parts package. This again raises the question of just how long can/will the new system be used successfully, a service life of 6–12 years is regarded as the standard here. However, control systems are being modernized after 8 years in some instances and are being repaired for up to 35 years in others. This depends significantly on the manufacturer and the availability of the components used. The transition to the new system should occur simultaneously without any substantial stoppages and re-commissioning procedures, which means that most of the functionality should be transferred from the existing system to the new one.
Without a Concept there’s Nothing!
What is particularly important is a clear modernization concept that covers several factors
- Elevation of the current status with data backup
- Hardware – rapid conversion, centralized or decentralized structures
- Safety consideration – risk analysis, implementation of the latest guidelines
- Functionality – where/ what intelligence is required for the components/modules used
- Data flow – what data is needed where and how is it needed
- Transfer possibility – everything should not have to be reinvented
- Service and spare parts availability – should be considered at the time of investment
- Consumption of energy/ resources – should be kept as low as possible in all areas
- Modification and commissioning period/ expenditure – should be as low as possible
- Economic efficiency/ added value – should always come first.
All Possibilities
Several possibilities are generated here for the operator, if individual modules/components used by smaller manufacturers are discontinued, a complete overhaul is often imperative. For standard industrial modules used by large manufacturers it is often much easier to acquire used or repaired hardware, even up to 30 years later. The level of know-how is also more widely available, thereby resulting in consequently improved maintainability.
However all types of mixed operations, i.e. use of the latest visualization and intelligent control modules in combination with standard modules that are up to 25 years old, such as I/O cards, are also possible. This results in economic advantages such as low investment costs and short conversion periods.
Worth Mentioning – Preventive Maintenance
In this challenging environment, it is even more important to identify opportunities and risks early on and to take the right decisions. The user of a production plant should think, plan and act with foresight and should be aware which components are operating in his control cabinet.
Preventive measures are not only used for extending the life of the equipment, the more important point is to keep it working. Industrial control equipment should be inspected periodically to avoid costly production failures and system standstills.
Experience shows that in particular, the time and effort for these preventive measures like repairs, maintenance, risk analyses, quality controls, proof of spare part availability, etc. … are often underestimated. This increases the risk that internal projects fail due to insufficient available resources. But only this preliminary work can open up potential for optimization – the use of external resources can be reasonable and economic.
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