Seattle Steam Optimizes Boiler Control with FOUNDATION Fieldbus
District heating company realizes advantages of reliable fieldbus control
solution
Seattle Steam is a district heating company located in Seattle, Washington. Founded in the late
1800s, the company maintains 18 miles of pipe buried under the streets of downtown Seattle ina one square mile area. Customers purchase steam for heating buildings and water, and in thecase of hospitals, for use in sterilization processes.
Although Seattle Steam's steam generating operation had been modernized several times overits history, the company had not upgraded its plant automation equipment in many years.
Management decided that a new boiler control system was in order. The project would involve
replacing outdated pneumatic controls that were increasingly difficult for plant personnel tomaintain.
Background
Because of the lengthy period between upgrades, Seattle Steam had no preconceived notions
about process automation technology. Control system selection began with a clean sheet ofpaper. However, plant engineers were most concerned about equipment obsolescence; as asmall company, Seattle Steam could not afford to replace its control system every 5‐10 years,
and thus required a solution able to evolve with new technology. The company also viewed
reliability as a key criterion.
After considering alternative approaches, Seattle Steam decided upon a FOUNDATION ™
Fieldbus‐based control system. At the heart of the system was a powerful, multifunction
hardware component that functions as an interface, linking device, bridge, controller, gateway,
fieldbus power supply, and distributed I/O subsystem.
The multi‐function hardware component, serving as a universal bridge, integrates all of thehardware and software needed to manage, monitor, control, maintain and operate the steam
plant boilers. Due to the use of open standards such as FOUNDATION Fieldbus and OPC, the unit
provides tight integration of intelligent devices supplied by various instrumentation vendors, aswell as the plant's human‐machine interface (HMI) software.
Selecting FOUNDATION Technology
For industrial organizations like Seattle Steam, FOUNDATION Fieldbus is a proven solution forimproving operational effectiveness, reducing costs and ensuring safety. It is also the rightchoice for a future driven by the Industrial Internet of Things (IIoT) and a connected enterprise.
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FOUNDATION Fieldbus allows industrial organizations to unlock the full capabilities of their
existing assets. By providing the means to leverage immense amounts of data generated bymodern automation systems, the potential uses and benefits are numerous. They range fromenhanced data collection and improved remote monitoring, diagnostics and asset
management, to reduced configuration and commissioning effort.
FOUNDATION Fieldbus provides an all‐digital communication infrastructure for process
automation, with powerful multivariable measurement capabilities, robust device diagnostics,
and the ability to integrate wireless devices across multiple networks. The block structure ofFOUNDATION Fieldbus is unique, enabling true distributed functionality, improved datamanagement, and alarm and alert management.
With FOUNDATION technology, multiple devices — each with multiple I/O signals — can sharethe same bus. Fieldbus‐based control systems employ two‐wire twisted pair cable and provide
intrinsically safe or non‐incendive device power suitable for all hazardous areas. Unrestricted
access to field device intelligence enables centralized configuration/setup and diagnostics for all
field instruments, including discrete sensors and actuators. This solution also supports
temporary masters such as handheld field communicators, laptops/tablets, and documenting
calibrators.
Unlike other digital architectures, FOUNDATION Fieldbus was designed from the ground up to
enable control‐in‐the‐field (CIF) strategies across the plant. This means that during a hostsystem failure, field instruments can communicate directly with one another to maintaincontinued safe operations. The technology includes a number of physical layers (the mediumthat the signal communicates through) and a rich software platform that allows for the over
1,000 registered products to interoperate between various manufacturers of devices andcontrol systems — offering end users the flexibility to choose best‐in‐class solutions for theirapplication.
FOUNDATION Fieldbus also supports the NAMUR NE107 recommendations for managing datafrom intelligent instrumentation. This ensures diagnostic data is managed effectively, and you
only see the information you need to see, when you need it.
Reliable and Flexible Control Solution
Process plants all across the globe choose FOUNDATION Fieldbus as an end‐to‐end digitalcommunication standard. Whether strict determinism, inherent disturbance rejection, or abroad base of registered devices matters most, FOUNDATION Fieldbus enables best‐in‐classsolutions for fully digital plant architectures.
FOUNDATION H1 (31.25 kbit/s) technology is designed specifically for field‐level interface anddevice integration within the process plant environment. It is the foundation upon which
Information‐driven systems offering increased connectivity, real‐time data, and advanced
analytics can deliver better performance and enhance competitive advantages—not only in theplant, but across the enterprise and out to its value chain.
2FOUNDATION H1 is an interoperable, bi‐directional, digital, serial, publisher‐subscriber
communications network, which is suitable for use in hazardous and potentially explosive areas(Ex zones 0 and 1), as well as intrinsic safety (IS) applications. Each H1 segment supports alength of 1,900 meters and connects up to 32 field devices, depending on the individualenvironment. These limits can be extended using bridges.
The FOUNDATION H1 solution enables field instruments and other devices to execute control
functions, thus reducing the load on plant computers and workstations. Since the H1 network isdigital, I/O conversion subsystems are eliminated.
Project Results
Seattle Steam was able to configure a simple, reliable, fieldbus‐based control system without
the complexity and cost associated with a legacy DCS. A single hardware module implements
four FOUNDATION Fieldbus H1 ports, and Ethernet and serial Modbus ports directly on thecontroller without the need for separate interface modules. As such, the unit requires a fractionof the space of solutions using individual modules, and is easier to install, maintain and expand.
Using FOUNDATION technology, field devices can handle continuous regulatory control for theboiler process. This approach restores single‐loop integrity and minimizes the chance ofintroducing errors into the process. Full redundancy and fault isolation also ensure increased
safety and uninterrupted operation. For example, plant operators can turn off their computers,
and as long as power is maintained to the fieldbus system, the boilers remain stable.
Most importantly, Seattle Steam realized significant hardware and installation cost savings byimplementing a FOUNDATION Fieldbus‐based control system. Compared to traditional single‐loopcontrollers, the fieldbus system reduced input/output (I/O) requirements and the labor
involved in wiring field instruments.
Conclusion
With a FOUNDATION Fieldbus control solution, Seattle Steam has a secure, affordable pathforward to new technology. The fieldbus‐based system has performed reliably during years ofcontinuous operation. That will help the company keep its customers warm well into thefuture!

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