FOUNDATION Fieldbus

FOUNDATION Fieldbus
Name	FOUNDATION Fieldbus
Type	Industrial network protocol
Developer	The Fieldbus Foundation
Introduced	1990s
Standard	IEC 61158 family
Use	Process automation, distributed control

FOUNDATION Fieldbus. FOUNDATION Fieldbus is a digital, serial, two-way, multi-drop communication system for industrial process automation designed to replace analog 4–20 mA signals with a deterministic, instrument-level network. It was developed by The Fieldbus Foundation and standardized within the IEC 61158 family, enabling interoperability among transmitters, actuators, controllers, and asset management tools in chemical, oil and gas, pharmaceutical, power generation, and water treatment plants. The technology supports distributed control, diagnostics, and advanced control strategies by embedding application-layer functionality into field devices.

History

Fieldbus development emerged from collaborative efforts among vendors, end-users, and research institutions during the late 1980s and 1990s to address limitations of point-to-point wiring in process industries. Key participants included The Fieldbus Foundation, ISA, IEC, ABB, Honeywell, Emerson, Yokogawa, Siemens, and Foxboro, which influenced specifications and interoperability testing. Milestones overlapped with standards work at IEC, ISA, and national bodies such as ANSI and led to normative entries within IEC 61158 and related IEC technical committees. The evolution paralleled advances in distributed control systems at vendors like Honeywell International Inc., Siemens AG, and Emerson Electric Co., and intersected with initiatives such as PROFIBUS, HART, and Modbus.

Technical Overview

FOUNDATION Fieldbus implements a layered architecture conforming to the OSI model with specific mapping to IEC 61158 and IEC 61784 profiles. The protocol supports two main variants widely deployed in process plants: H1 (31.25 kbit/s) for intrinsic safety and device-level communications and HSE (High-Speed Ethernet) for controller-level and backbone connectivity. Devices exchange data using scheduled token-passing and publisher/subscriber paradigms, enabling cyclic and acyclic messaging for control, configuration, and diagnostics. Key components include device description language (DD), function blocks for control algorithms, and device revision management, integrating with asset management systems from vendors such as ABB Ltd., Schneider Electric SE, and Emerson Process Management.

Network Architecture and Protocols

The architecture segregates field segments, linking field devices to host systems via link active scheduler (LAS), linking devices like smart transmitters and valve positioners. H1 segments typically use Manchester-encoded Manchester II signaling over twisted-pair or intrinsically safe barriers in hazardous areas governed by standards from IECEx and national approvals like ATEX. HSE leverages Ethernet standards such as IEEE 802.3 and may interoperate with IEEE 1588 Precision Time Protocol for time synchronization. Protocol suites include Foundation Communication Entities mapped to IEC 61158 types, with network management, discovery, and firmware download supported by common industrial services used by DCS vendors including Yokogawa Electric Corporation and Honeywell.

Implementation and Instrumentation

Field devices implement FOUNDATION Fieldbus stacks and device description files enabling interoperability among sensors, actuators, and controllers. Typical instrumentation includes smart pressure transmitters from Emerson, Coriolis meters from Endress+Hauser, magnetic flow meters from ABB, and valve positioners from Fisher Controls integrated into plant DCS products such as General Electric (GE), Emerson DeltaV, and Siemens PCS 7. Implementation involves wiring topology planning, segment length and trunk/drop design, power supply and field power considerations, as well as commissioning tools provided by manufacturers and third-party vendors for function block configuration, calibration, and diagnostics.

Safety and Reliability

Safety-related deployments apply intrinsic safety techniques and redundant architectures to meet SIL requirements under IEC 61508 and industry standards such as API guidelines for process safety. Redundancy can be achieved through duplicated HSE networks, redundant link active schedulers, and redundant controllers from suppliers like ABB and Honeywell International Inc.. Diagnostics and device health monitoring enable predictive maintenance strategies used in facilities operated by companies such as ExxonMobil, Shell plc, and BP plc, improving mean time between failures and enabling compliance with regulatory frameworks overseen by agencies like OSHA and international classification societies.

Adoption and Industry Impact

FOUNDATION Fieldbus saw adoption across heavy process industries including petrochemical, refining, pharmaceuticals, and power plants, driven by the need for reduced wiring, richer diagnostics, and distributed control architectures. Major end-users such as Saudi Aramco, Chevron Corporation, and Dow Chemical Company participated in early deployments and interoperability testing. The technology influenced the development of other industrial protocols and converged with initiatives in industrial Ethernet, Industrial Internet of Things concepts advocated by organizations like IIC and IEC. Market dynamics involved competition and coexistence with protocols including PROFIBUS, HART Protocol, Modbus, and EtherNet/IP.

Standards and Compliance

FOUNDATION Fieldbus specifications were incorporated into the IEC 61158 standard as specific fieldbus types and are referenced in IEC 61784 profiles for real-time communications. Compliance and interoperability testing are coordinated by The Fieldbus Foundation and accredited test houses, with certification programs covering device conformity, intrinsic safety approvals, and EMC compliance per IEC 61000 series. Regulatory and industry guidance ties into functional safety standards such as IEC 61508 and sector-specific standards from API and NFPA.

Category:Industrial automation Category:Fieldbus protocols Category:Process control