1. Growing lack of knowledge
Many distributed control systems in process plants are reaching the end of their useful lives. Some systems have functioned well for over 30 years! Why would you consider upgrade/migration now? Factors such as retirements and layoffs result in a decrease in expertise in the current DCS, which may have been operating longer than any company employee. Eventually there will be no one left with any (specific) knowledge about the obsolete DCS. Before this happens you may want to migrate the obsolete DCS and familiarize the younger engineers with the new technologies that follow.
“Your business should be in control of your control system, not the other way around”
2. Upgrading/ migrating your DCS at the absolute end of its lifespan is very unwise.
Upgrading/ migrating a DCS requires planning. Last minute upgrading/ migrating could lead to unforeseen problems. Therefore, planning ahead is mandatory to the replacement of the current DCS. All complete DCS migration project, including planning and executing, could take years. Migrating your DCS before it stops working is therefore a wise thing to do. This is safer, more efficient, less costly and less risky. The most important thing is to be in control of your system and not the other way around.
3. New systems allow for configuration possibilities.
Older systems are only configurable for a limited number of controls. Advanced regulatory techniques can directly be implemented in new DCS systems.
4. DCS migration costs versus DCS maintenance costs.
The maintenance of older systems become more expensive as they grow older. Spare parts are expensive and not easy to come by. Also, unplanned shutdowns result in production loss, which increase your costs. The costs of a DCS migration will therefore become cheaper than the necessary maintenance to your old DCS.
5. Old systems are not compatible with new technologies.
The old DCS are often not able to communicate with third party systems. These systems, such as SAP, MES and ERP, can be very beneficial to your company.