Every DCS faces obsolescence after their long and useful life. When obsolescence makes it hard to work with the current DCS any longer, it is time to consider a DCS migration. This requires extensive planning, financial justification and answers to many difficult choices. You can find more information on these topics in previous articles:
- DCS migration checklist; planning of distributed control system migrations.
- Distributed control system migration approach; important choices when considering a DCS migration.
- Financial justification of DCS migrations; Return of investment & 5 financial justifications
Why consider a DCS migration?
1. Obsolete by original equipment manufacturer
When spare parts for the current (obsolete) DCS become harder to come by, migration will be a good consideration. If not because spare parts for a new DCS will be much easier to find, then it can be financially justified by the fact that spare parts for the obsolete DCS will become very expensive due to scarcity. Also, expertise for the current obsolete DCS becomes scarce, while expertise for the new DCS is growing.
Throughout the 25 years of functioning well, the DCS was operated by a couple of (expert) engineers. Many of these engineers have retired and took their expertise with them. Newly hired engineers, which were mainly educated in the operation of new DCSs, do not have the expertise to operate obsolete DCSs. Let alone to recognize necessary maintenance, problems and risks. This would require training new engineers to operate obsolete DCSs, which is highly inefficient; the obsolete DCS will start failing sooner rather than later. Therefore it is recommended to start the migration process to a new DCS before real problems and risks start to occur.
2. Lack of production data
A lack or production data might also be a consideration to start the migration process. While your old DCS still provides you with data about the production process, this might be inadequate. New technology created many new opportunities. The obsolete DCS has been running for many years without renewal of the technology. The new DCS with innovative technologies results in better visibility and easy access to plant and production data for better decision making.
3. Limited network and/or expansion options
Some distributed control systems do not have open communication options. While new control system have real-time information available throughout the enterprise for better decision making. These control systems can be integrated to process networks such as HART, Fieldbus and Profibus. Also, when a plant is expanded and the existing control system is still supported, many companies do not want to install obsolete technology on new process units. Therefore, they will migrate to a new DCS.
4. Technical end of life
Some distributed control systems have grown obsolete and are showing small failures which eventually grow into big failures. This causes a growing concern about the reliability of the DCS. Often data shows the occurrence of failures that do not immediately have an impact on control, but indicate that reliability in the future might become a problem. Companies endeavor a reliable and stable process and are therefore recommended to start planning a DCS migration as soon as the reliability of the obsolete DCS becomes questionable.
5. Lack of flexibility and production efficiency
The lack of flexibility and production efficiency of obsolete DCSs has been changed to a great extent by introducing scalable and flexible DCS solutions. “Today’s scalable and flexible DCS solutions enable process end users to extend their scope at any time from process control and management to include personnel and assets, and to even integrate the resources of their entire business operation” (Honeywell, August 2016).
Reasons enough to consider migrating from an obsolete DCS to a new DCS. A big challenge will be to financially justify your plan to start migrating to the ones holding the company purse. You will find more information on this topic in one of our previous articles.