Control system endurance
A common discussion across manufacturing industries is: How long should a control system last. The right answer to this question is: As long as you need it to.
Your control system was a significant capital investment when it was first purchased, with a projected life expectancy that should have well superseded the pace of subsequent new technology developments. Your company also invested many hours of engineering, configuration, and training to bring the system on line and to perfect the process. The investment, both intellectual and capital, in this existing system is substantial. Your challenge is to increase its value, extend its life, and lower costs without jeopardizing current performance.
Your process control system’s infrastructure should be able to provide you with years of useful service; and offer you the potential to build upon its base to add new capabilities, features, and functions that adapt to your ever-changing business needs. For example, back in 1990, who would have thought that integrating automation and electrical systems would be possible, to provide the competitive advantage it does now?
Some may argue that it makes business sense to completely discard this investment, rip out the old and just start with a new system that incorporates the latest technology. In addition to being very expensive and disruptive to production, this approach discards engineering effort, process knowledge and years of application work. With such a rip-and-replace approach, invaluable best practices for engineering, operations and maintenance are lost, as is the physical infrastructure such as wiring and I/O. Production comes to a complete stop for an extended period of time—all for a one-time improvement opportunity.
Another approach to a control system upgrade is to just replace the HMI. In many of these cases, suppliers develop interfaces to the proprietary controller products of their competitors. On the surface, this approach may appear to be less disruptive, but in reality it has long-term consequences that will lead to the costly replacement of the entire control system. While vendors may say these solutions protect control hardware investments (e.g., wiring, terminations, cabinets), they neglect the heart of the control system: your field-proven control strategies. This virtual rip and replacement is extremely costly because it requires the user to re-engineer, re-test, re-document, and re-commission existing applications.
The more progressive and far less radical way to move forward is to add desired features and functionality in a planned, stepwise fashion. These incremental additions help you to get better performance out of your existing control system while incorporating the advantages of today’s new technologies. You can integrate your system with areas and systems in the plant to produce results that weren’t possible just a few years ago.
This evolutionary control system approach is simply the continuous process of updating control systems with current technologies so that operations remain competitive. Evolution should be an incremental process, and it should use your existing installation as the foundation for change.
Several specific capabilities/approaches are necessary to evolve a control system successfully:
The mindset that existing applications will be the foundation for future productivity improvement; this requires portability and reuse of existing applications;
Integration of new technology with that of the existing installed system;
Consistent look and feel of new operator environments with those being upgraded;
New technology added with minimal disruption to production;
Product lifecycle support that enables step-wise system upgrades over extended periods (5-7 years) while having access to compatible hardware, software, and security updates;
Extension of the system user view to include all automation applications from a single operations environment;
New technology introduction driven and justified by business needs; and
Long-term planning that looks beyond the next business challenge.
For users who aren’t quite ready to expand their control systems, comprehensive service and support are vital tools for getting the most out of an existing system investment. There are a number of products that will help you keep your system running at peak performance, including engineering resources offered by your control system vendor or system integrator, comprehensive telephone and online support for your existing system, software maintenance subscription programs, and other options.
Mark Taft is group vice president for ABB’s Control Systems Business.