Best practices in control system migration

ControlGlobal.com

Keywords: control system and migration

Migration from your old control system to a new one is as an inevitable as death and taxes. But, the key to minimizing the pain is to abide by the control system migration best practices listed here.

By Dan Hebert, PE, Senior Technical Editor

Migration from your old control system to a new one is as inevitable as death and taxes. But unlike dying and paying taxes, you will be better off after a control system migration than before. That’s the good news.

The bad news is that the migration can sometimes be just as painful as paying taxes, if always a little better than death. The key to minimizing the pain is to abide by control system migration best practices. Here, culled from recent interviews with a host of our readers—your peers—is the roadmap for the minimal-pain upgrade.

When to Migrate
The most important control system migration best practice is knowing when to jettison the old in favor of the new. Lack of spare parts for the old control system’s hardware is the leading reason for replacement. In essence, the vendor has made your system obsolete by its decision to discontinue support.

WHEN TO MIGRATE Don’t upgrade until obsolescence threatens Don’t install soon-to-be obsolete hardware on new processes

“We often replace non-standard proprietary controller for various clients,” reports Bob O’Brien, principal engineer at CSIA member Concept Systems “Such controllers are prone to becoming obsolete, making service very costly and replacement parts hard or impossible to get.”

One end user justified migration based on pending obsolescence. “Our main justification for the migration was concern about the reliability of our Honeywell TDC 2000 system due to its age and spare parts availability,” says Jaime Salom, CSEE and principal instrument engineer at Lyondell Chemical Company (Houston, Texas). “Our data showed some occurring failures that weren’t impacting control, but indicated that reliability in the future might become a problem.”

FIGURE 1: TIME FOR A CHANGE
Non-standard proprietary controllers such as the one shown at the upper left of the panel are prone to obsolescence, making service very costly and replacement parts hard or impossible to get. Image courtesy of Concept Systems

Even when an old control system remains supportable, there can be good reasons for replacement. “Our migration project was undertaken in conjunction with a plant expansion,” reports an anonymous end user at a Midwestern petrochemical company. “The existing control system is still supported, but we did not want to install obsolete technology on new process units.” 

Obsolescence does not happen on a specific date, but rather is a gradual process that starts with a vendor discontinuing support. Spare parts then become harder to procure and more expensive. At some point, spares become too expensive or too hard to find, obsolescence becomes inevitable and migration must occur.

Once the decision has been made to migrate, the first task is deciding on a partner. Options range from a vendor to a system integrator to an engineering firm. In each case, quality of service should be the deciding factor.

Service is Key
One end user and system integrator after another reiterated the same point: All the major vendors make good hardware and software. No one should make a decision about vendors based on claims about hardward and sofware perforamnce, because all the stuff is pretty good.  

The big differences arise when it comes to service, and you will require lots of service and personal attention from vendors before, during and after a control systems migration. “Our experience with migrations has been mixed,” reports Mark Hall, the IS and applications engineering manager at leading refiner Hess Corporation (New York).

“The technology offerings are all solid and perform reasonably well, but support has been marginal at best. There is a core team of experts at the vendor that are very well-versed on the technology and implementation strategies, but the level of expertise falls off quickly from this point,” concludes Hall.

Another end user voices concerns with vendor service. “Vendor support has a way to go yet. Smaller local service firms offer more bang for the buck than the factory-trained guys with the OEM logo on their hats,” says Patrick Loupin, a technology resources manager at papermaker Boise Cascade (Boise, Idaho).

The contrast between vendors with respect to service is stark, “Exceptional coordination and planning by Yokogawa made for a well-executed migration plan,” claims Jim Peppers, an instrumentation process engineer at the chemical manufacturer Hexcel Corporation (Stamford, Conn.). “As different processes in the plant were starting up, Yokogawa provided application engineering support around the clock,” adds Peppers.