Electronic Marshalling: Put Time on Your Side

Whether Modernizing or Building New, Electronic Marshalling Can Buy Time When You Need it Most.

By ControlGlobal.com Staff

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Daniel Santos Monasterios Morales knows what it's like to be on a project's critical path. He's been there.

Automation manager for Braskem's petrochemical facilities in southeastern Brazil, Morales oversaw a recent control system modernization project for one of the company's polypropylene production facilities. Two factors weighed heavily on the company's modernization plan: the desire to re-use existing field wiring, and the need to fully execute the transition to a new control platform within a narrow 15-day turnaround—only a fraction of which could be used for automation activities.

"In the limited time available, it would have been impossible to migrate this system using traditional methods," Morales says. Enter Emerson Process Management and its Electronic Marshalling technology. The migration team tested everything on the new DeltaV system out beforehand, and when it came time for the switch, "We just moved the old FTAs [field termination assemblies] out, and the CHARM I/O cards in. This was straightforward because we didn't have to concern ourselves with rearranging cables from the field," Morales says.

Morales estimates that the flexibility of the Electronic Marshalling solution allowed them to design and install the new system in 50% less time compared with conventional I/O approaches. The team met their "impossible" project deadline, and the plant was back up and running on schedule. Further, Morales credits this approach with a 19% installation cost savings and a 15% design cost savings.

Read Also: What Could You Do with I/O on Demand?

For Braskem, the truly critical-path time savings afforded by Electronic Marshalling was in the system installation and commissioning. With this approach, once the new CIOCs are in place field technicians can quickly land the existing field wiring on any available I/O channel without regard to type. Subsequently, each channel is given its appropriate character by simply plugging in the appropriate type of characterization module, or CHARM. The mapping of each I/O point to the appropriate controller in the system is done through the DeltaV system software with very little effort. In the end, Electronic Marshalling can save time and prevent mistakes just when the migration team is under the most pressure to get the plant back up and running.

HCD in the Details

While Electronic Marshalling represents a conceptually different approach to doing automation projects, Emerson's focus on human-centered design (HCD) also is apparent in the smallest implementation details that can streamline system installation and commissioning tasks. For example, the DeltaV CIOC itself has been designed for ease of use, both in physical installation and its software tools. Components snap together with secure DIN-rail latches and interlocking carrier connectors; a series of 96 I/O channels can be connected to a DIN-rail in a matter of minutes.

No tools are needed to remove a CHARM or CHARM terminal block from the baseplate. Upon initial insertion, CHARMs are sensed by the system, automatically creating the I/O definition in the DeltaV configuration database. Also, upon initial insertion of a CHARM, each terminal block is "self-keyed" such that the wrong type of CHARM cannot be mistakenly inserted without removing and manually resetting its terminal block (again, without tools).  CHARMs also can be partially ejected to a stand-by position, disconnecting the field wiring from the system to perform field maintenance actions or to remove power to a field device. Activating the CHARM latch ejects the CHARM to the stand-by position. Closing the latch locks the CHARM in place and isolates the field wiring for field work.

For Glen Pfeifer, controls specialist for chemicals manufacturer E.R. Carpenter LP, a recent control system retrofit at its Pasadena, Texas, facility "worked out wonderfully" with Electronic Marshalling technology. The modernization project involved new DeltaV control and safety instrumented systems for two units, each consisting of 550 I/O points.

They reused the old systems' remote I/O cabinets, landing new wires from newly installed remote CIOC field enclosures on new terminations installed on stand-off brackets in the old remote I/O cabinets. "We were able to completely commission the new controls, the network and the CIOCs all the way to the new termination points in the old cabinets," Pfeifer says. When it came time for the cut-over, "we just lifted the wires off the old I/O card, landed them on the new terminals, and—boom—it was talking."

Commissioning definitely went faster than with traditional approaches, Pfeifer adds, citing the ability of each I/O channel to self-identify and self-configure. "The simultaneous enabling and downloading of multiple I/O channels was helpful; the system software worked just as I expected it to, and for the most part I couldn't think of a better way to do it."

An Earlier Start

While Electronic Marshalling shines under the pressure of a retrofit cut-over, its ability to save time and associated expenses is perhaps even more apparent in greenfield projects. Here, time can certainly be saved in installation and commissioning, but the real game-changer is in the ability to start automation system design earlier in the overall design process.

Classical marshalling, the old way of doing I/O, is at the heart of a labor-intensive, relatively inflexible work practice that also is subject to the whims of late-stage process design modifications. Changes in process design drive changes in control system inputs and outputs required, and proceed to cascade through all that detailed engineering work—from reworking drawings to control system partitioning to building new cabinets. Late design changes are inevitable, but they add cost, time, and most importantly risk to any project. The practice of wired marshalling only intensifies these problems. But what if the nature of any single I/O channel could be changed at will, at any time during a project? What if all marshalling cabinets and junction boxes were of a "standard" design, and need not be engineered beyond knowing an approximate total I/O count? That's precisely what Electronic Marshalling brings to the table. As a result, it effectively removes I/O from the critical path of many projects—decoupling process design from I/O architecture decisions as well as eliminating the rework costs and project delays that were once the inevitable consequence of late-stage design modifications.

While important to owner-operators, the technology also has proven popular among innovative engineering and procurement contractors like WorleyParsons, which engineers, designs and builds plants and platforms and works with Emerson to provide the automation systems. "As our customers ask us to take on increasingly large, complex projects -- often with fast-track schedules—changes late in the design process are inevitable," says Robert Armstrong, chief instruments and controls engineer, WorleyParsons.  "Electronic Marshalling streamlines how projects are designed and engineered and as a result, has helped control the cost and schedule impact of last-minute changes."

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