The scenario: A decision-maker determines that it’s justifiable to commit capital dollars to replace a legacy control system with a more contemporary automation system. Questions then begin to surface: Do we just replace like-for-like? How big of a cutover period will production give us to rip out the old and put in the new? Are there inherent problems with the legacy system that we should correct as part of the project scope? Are there ancillary systems that will also need to be replaced along with the legacy control system? Is our instrumentation adequate, working and accurate? Should we increase our data mining efforts on the system to create better analysis tools for management? Do we embrace mobility technology? Do we spread this migration across multiple years because of the complexity or overall cost?
The answers that bubble to the surface to these questions can produce a wide range of results. The right combination of answers along with engaging a competent integrator partner can lead to significant and noticeable improvements in the plant’s operation. Let’s touch on the wheres and hows.
Let’s face it—risk factors, time and money (mostly money) are the big influencers on these migration projects. But when is it time to undertake a control system migration? It’s time to migrate when replacement components are only available on eBay or Craigslist. Or when the legacy system is so old that only one guy in the entire country knows how to troubleshoot and maintain the system. Or the plant manager stresses when daily production quotas cannot be met because the old control system routinely faults, the operators and maintenance struggle to find the root cause, thus greatly disrupting manufacturing workflow. These consequences, and a whole lot more, can all be addressed with the proper plan and the proper partner.
Migrations of legacy control systems can be the catalyst to making improvements in the process operation, process control, quality control, change control, traceability, documentation, on-site and remote technical support, predictive maintenance, energy management, system security and longer-term system sustainability. Replacing like-for-like does not typically provide the opportunity to enhance the usefulness of the new automation system for the stakeholders.
Migrations do not necessarily need to steal an inordinate amount of cherished production time for the cutover with proper planning and execution. Capital budget limitations can be overcome by developing a multiple-year plan based on a phased migration model that is well thought out. Technology platforms can be advantageously used, such as physical-to-virtual (P2V) server conversion, I/O converter kits, and EtherNet/IP gateways, to help bridge between old and new when the migration is not all performed at the same time.
Existing operational problem areas can be addressed during the migration, and the project budget most likely will not experience a sizable burden because some of the issues operators and maintenance deal with are easy fixes to the control code or HMI. Migrations can use industry-accepted programming and graphical standards to make the operator’s day-to-day job more efficient and effective as well as make the OT engineer’s and OT technician’s ability to troubleshoot much quicker, saving precious production time.
Legacy control system migrations are the ideal time to add automatic data archiving, data mining and reporting where manual record keeping and word of mouth were the primary methods for monitoring, tracking, notifying and documenting the manufacturing operations. An additional investment is typically included in the project’s capital budget for this system enhancement. And the payback, in many cases, is almost immediate as clients routinely glean process and operational information from the data system that had been previously masked, unnoticed or unknown. Properly designed, specified, configured and verified, the automatic data and reporting system will most definitely become an essential tool for production, maintenance, quality and management to use to drive operational improvements.
Legacy control system migrations are common in today’s manufacturing plants, but the projects should not be commoditized and should not just be done as cheaply as you can. Take the opportunity to create a suitable project budget and engage the services of a qualified and capable integrator partner. Together, formulate a migration plan to a sustainable automation system that not only addresses the needs of all stakeholders within the manufacturing company, but also provides them with the means to drive operational improvements and add to the company’s successes.
Steve Malyszko, P.E., is president and CEO of Malisko Engineering Inc., a certified member of the Control System Integrators Association (CSIA). See Malisko Engineering’s profile on the Industrial Automation Exchange.
