There may be reasons why you need to consider something beyond your automation system that has been running in your plant for years and years. It might be the need to more tightly control energy usage to reduce energy costs. It might be to improve quality and consistency to stay ahead of your competitors. It might even be that you are losing peoples’ expertise to retirement to maintain this automation system.
The vernacular for this process varies–modernization, migration, or upgrade–but planning is an essential component. I caught up with Laurie Ben, who directs a team of modernization consultants in Emerson’s Process Systems and Solutions business. They have expertise in Emerson systems and systems from other automation suppliers. They also have methods and tools to design a migration solution.
This migration process can range from a simple connection between systems all the way to a “rip and replace” project, depending on the business drivers prompting the change. Some plants have existing pneumatic and panel-mount controls. Downtime and reliability concerns often provide the justification required to transition these to the current digital communications-based systems.
These digital technologies provide ways to do hot cutovers to keep the process running while the automation is migrated from pneumatic to digital. An example of how this works is a Fisher Foundation fieldbus-based DVC6000f digital valve controller. Its pressure control functionality connects to a DeltaV system while also sending a pressure signal to the existing actuator or pneumatic positioner. Once these pressures are balanced within the system, control is transferred to the digital valve controller. During this phase, AMS Device Manager helps finalize the cutover by helping the team to communicate locally with the valve to monitor exactly what is happening during the process of mounting, adjusting, stroking, and calibrating the valve.
Laurie mentioned that operator consoles typically have the shortest life span of all the automation system components. It is often the first consideration for migration to a modern automation system. Newer operator workstations keep the look and feel of the operator graphics and faceplates and connect to the existing automation system. Over time, I/O and controller hardware and software can be migrated. The business drivers help dictate the pace of migration.
For instance, if energy cost reduction is the business driver, it may make sense to modernize the controller and I/O to get embedded advanced control capabilities. Units like lime kilns, fired heaters, boilers, etc. can be run more efficiently as a unit with model predicted control than as a collection of interdependent loops.
It really begins with your business drivers and developing a plan to move forward to modernize your automation. The hardest path is to justify it based on obsolescence since the calculation of ROI based on problem avoidance. The best path is to find cost reduction or efficiency-improving opportunities. These numbers are the basis for your financial justification calculations.