Even in the cheapest real estate markets, control room space comes at a premium. But what if your plant has run out of elbow room, and company planners are itching to put your control room floor space to more productive use?
Such was the situation described by Eric Phares, automation engineer at Johnson Matthey's West Deptford, N.J., facility, where a range of active pharmaceutical ingredients (APIs) are produced. The company is in the process of migrating older Emerson PROVOX control systems over to the DeltaV system. And for the unit in question, they chose to go with Electronic Marshalling in no small part because it would allow them to readily move the system I/O out of the control room and into cabinets distributed throughout the production environment.
"Electronic Marshalling allowed us to distribute that I/O out to the process," Phares explains. "It gave us the opportunity to use that space for operations instead of a place to hang computers. And for a small facility like ours, even a hundred square feet is a big deal," he says.
The control room that was once the home-run destination of hundreds of instrument wires now holds only a single DeltaV workstation—and that's likely to go, too, in anticipation of the control room's eventual demise. Now, instead of bundles of copper running back to the old control room, the 17 field enclosures feed six CHARM I/O card (CIOC) enclosures fiber optically linked to a DeltaV controller cabinet and six DeltaV workstations, all of which are situated in the Class I Div 2 production floor environment.
Johnson Matthey also is reaping performance and functionality benefits with the new system. "Instrument techs have remarked that the Electronically Marshalled instrument loops are performing more precisely," Phares says. And, now that the new system is in place, they're adding new functionality starting with the automating of reactor inertion and pressure testing sequences that weren't readily doable with the old system. "Now we can, so we do! We have the ability to make a lot of good things happen now," Phares says.
Built for Offshore Demands
From the very start, Electronic Marshalling was intended not only to collapse project schedules and reduce engineering and installation effort, but also to address the often extreme space and weight limitations of offshore production platforms. The effective elimination of marshalling cabinets was a huge first step toward smaller I/O cabinet footprint. Further, with the introduction of intrinsically safe CHARMs, the need for separate third-party barriers—and all the engineering that went with them—has disappeared as well.
The ability to install Emerson's CIOCs in standardized field enclosures with standard wiring out to the instruments and a fiber optic network link to the rest of the system reduces control room I/O cabinet requirements to essentially zero, as well as reducing the amount of copper wiring required, an added weight savings bonus for offshore installations.
BG Rashpetco, an Egyptian natural gas producer, took advantage of these new system features recently when it modernized the controls on a gas metering skid. They chose the DeltaV platform to improve connectivity with other process control systems, but Electronic Marshalling also paid off in saved space and installation time. "We used intrinsically safe CHARMs, which significantly reduced the cabinet size because we didn't have to include separate barriers and terminations," says Mostafa Lakosha, instrumentation and control engineer. "This also reduced the time required for installation."
Another big advantage is that can we can use just the number of I/O necessary," Lakosha adds, "instead of buying extra cards to accommodate the I/O mix we needed."
Reduce and Reuse
Meanwhile in South Africa, AEL Mining Services, a manufacturer of mining-related chemicals and explosives, was able to both reduce system footprint and reuse its existing marshalling cabinets during a recent control system modernization project, according to Leon Clulee, senior project manager for AEL. Fortunately, the AEL team had room to install the new CIOCs inside the existing system marshalling cabinets. "We got the new system up and running in parallel," Clulee explains, "and were able to shutdown and switch over quite seamlessly. Some loops were even switched over while the plant was running."
The old marshalling cabinets—which now double as the new I/O cabinets—are connected via Ethernet to the now sparsely populated controller cabinets. "The DeltaV controller now sits in one corner of the cabinet," Clulee says. "We saved four square meters of floor space, and are going to move other servers in there now."
With the modernization to the DeltaV system, the company also saw control performance improvements. For example, a boiler that had been run in manual for decades now runs consistently and predictably in automatic mode. "We're running more efficiently, and operators are freed up to do other tasks," Clulee says. "Operators can walk the floor to see what needs attention, rather than just staring at a screen. They have more time to look at what can be improved instead of doing mundane tasks."
"We're currently rolling out the same approach to the rest of our chemical plants, installing the CIOCs inside existing cabinets while the plant is running, ‘dry-commissioning' the system while the plant is online, and then taking the opportunity during a plant shutdown to changeover the control to DeltaV. The installation and configuration process is quite painless."
These plants will all be linked together via a redundant fiber optic network, putting all of the plants on the same control platform. Plant operators who once controlled the units in isolation will now have better visibility upstream and downstream, and into how the performance of their unit impacts the bigger system.