Pulp mill claims a foundation fieldbus first

InTech, Oct 1997 by Mangano, Jason, Dumdie, Dan

Daishowa is using the first production fieldbus installation demonstrating multiple-vendor interoperability with closed-loop control.

Port Angeles, Wash.-A Daishowa America pulp mill has staked claim to being the first (nonBeta) production installation of Foundation fieldbus demonstrating interoperability among multiple vendors with closed-loop control distributed in the field devices.

The installation at Port Angeles, Wash., which saw a successful start-up June 3, 1997, currently includes two fieldbus hosts and six fieldbus transmitters with two closed loops, six analog inputs, and five analog outputs.

[Editors note: Dow Chemicals Ft. Saskatchewan plant claims the first commercial application of products conforming to the Fieldbus Foundation's final specification. However, that installation primarily involved a single vendor's (Fisher Rosemount) equipment. See June 1997 InTech, page 15.]

The fieldbus technology is being used to control a refinery hydrogen peroxide bleaching process in a mechanical pulping facility and will facilitate brightness optimization, chemical usage reduction, and chemical tracking. The project introduced fieldbus technology to Daishowa and offers a path forward-away from old, high-cost DCS technology (vendor dependence) to lower-cost standard fieldbus technology (vendor independence).

Daishowa's fieldbus project takes advantage of many features listed in the Fieldbus Foundation's final specification. The process uses analog output (AO), analog input (AI), and PIDcontrol function blocks in field devices for controlling and monitoring the process. Interoperability is demonstrated by two different manufacturers' devices operating on one fieldbus H1 segment. SMAR International provided redundant fieldbus power supplies; all fieldbus devices, including six transmitters, each with multiple I/O (AI or AO function blocks); and a PID-control function block. National Instruments provided the host software and hardware. This included a fieldbus configurator, an operator interface (Lookout), utility software, and fieldbus interface PC cards. Relcom provided the fieldbus power multiplexer (for redundant power supplies and battery backup), power conditioner, impedance controller, bus terminators, and all fieldbus spur connectors.

The configuration was done on the host and downloaded to the field devices. The host also serves as the link active scheduler (LAS) and communicates with field devices to obtain process information and trends for operations. Daishowa was able to purchase and evaluate all software and hardware (starter kits) available for fieldbus applications prior to engineering the project. This ensured selection of the best available components.

The ability to download a configuration from National Instruments' hardware and software to SMAR International's fieldbus devices clearly demonstrates interoperability and its benefits. Verbal communications among these vendors before and during start-up was excellent and helped make the project a success. Fieldbus technology is not only important for the peroxide project but will also play a major role in Daishowa's future. There are significant savings associated with fieldbus control hardware, wiring reduction, maintenance, and system checkout when compared to DCS technology. Equipment costs are reduced because the control hardware, I/O, and communications hardware are all contained within the field transmitters. Air-conditioned rack rooms with raised floors for cabling are unnecessary.

There are no separate control cabinets, I/O cabinets, large power supply cabinets, nor any control and I/O modules, communications modules, control and I/O racks, or separate termination units and associated cabling. The equivalent to all of this is contained in the field transmitters.

In the near future, a significant amount of preventive maintenance will be done online in field devices. The conduit and wiring cost will be 40% to 60% less than for DCS installations because only one twisted pair is used to interconnect many field devices. Finally, engineering costs will be significantly reduced due to the decreased number of cabinets and hardware devices used in a fieldbus installation.

The peroxide bleaching process was chosen as the first installation for fieldbus at Daishowa. Using fieldbus controls rather than DCS control resulted in about 55% capital savings. This was critical since the project was initially rejected based on cost estimates, further justifying the decision to go with fieldbus technology.

The success of this technology gives the mill altematives for future control installations and upgrades. A second fieldbus project, planned for the fourth quarter of 1997 in the mechanical pulping facility, will be significantly larger than the first project.

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