3 min read

Saying Goodbye To Your Favorite Control System

If you are like me, you loved your first car. Nothing since has felt so solid. So reliable. You knew the car and the car knew you. And I bet you feel the same way your legacy DCS system. You know your control system inside & out. The controller & I/O feel as sturdy as a tank. You know the purpose of every button; you know every fantastic feature; and you appreciate every wart. But you have to say goodbye. Just like your first car, your control system is now obsolete and now needs to be replaced. It is time to start shopping.

Do you want your new DCS to be exactly like your old one? You may want to say yes. However, as much as you liked your old car, you may now never want to be without a backup camera, GPS navigation, heated seats, or a moonroof. So what about your DCS? You should be asking if your DCS graphics promote abnormal situation awareness? Do you need to do an alarm rationalization exercise? How does your DCS fit into your organization’s convergence of IT & OT? Do your engineers need visualization from remote locations? The bottom line is that when you migrate your DCS, you should be looking to gain as many benefits as you can from this process.

At the same time, you need to figure out how best to minimize the impact to operational schedule(s). Therefore, we need to determine how to perform your DCS modernization when it most likely operates 24 hours every day of the year. How does anyone do it?

When it comes to a DCS modernization we have two primary options: complete decommission and new installation (rip & replace) OR a phased implementation. Your DCS has three primary components: I/O modules, controller(s), and an HMI (graphical front end). With the first option, you take your operation down and replace all three at once. The phased option allows you replace one component at a time.

Which option is best? That depends. If you can afford a long enough shutdown, then the complete rip & replace will likely be the most cost-effective option. However, if you cannot afford the required shutdown time, then the phased approach begins to have advantages. It is likely you can upgrade your DCS graphics (HMIs) with minimal to no operational downtime. In the second phase of your migration, you can upgrade your DCS controllers, with minimal downtime. Finally, you can upgrade your I/O wiring and modules as your downtime schedules permit.

Sounds easy. It can be but it could also go poorly. Any modernization option is going to require rigorous documentation and testing to ensure a successful project execution. ACE recently performed a full rip and replace migration project for a legacy DCS system. Planning, implementation, and upfront testing took two years but the entire DCS was successfully migrated in only ten (10) days.

What should you be doing now? Come up with a plan. What are your production & shutdown schedules? Have you decided on an upgrade technology? Do you need to upgrade your communications backbone? What other stakeholders do you need to consider for the migration: IT, QA, etc.? What physical or parallel upgrades need to happen at the same time?

When you start to address these questions, ACE can assist with an upfront engineering effort to address how to achieve your objectives and schedules. We should start by developing a project execution plan and schedule. This schedule should include physical installation, commissioning & testing, and operator training. Once you are able to see the project plan in place ACE help you determine if a rip an replace or a phased migration makes the most sense for your system.

You may not want to say goodbye to your old DCS but ACE can help you begin to love your new one. And just like heated seats, we are sure that there will be new features you will quickly find out that you cannot live without.

Learn more about our approach to the modernization of legacy systems here.