The Fieldbus Foundation is the leading organisation dedicated
to a single international, interoperable fieldbus standard.
Established in September 1994 by a merger of WorldFIP
North America and the Interoperable Systems Project (ISP),
the foundation is a not-for-profit corporation that consists
of more than 350 of the world's leading suppliers and
end users of process control and manufacturing automation
products. Working together, these companies have provided
unparalleled support for a worldwide fieldbus protocol,
and have made major contributions to the IEC/ISA fieldbus
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FOUNDATION fieldbus is an all-digital, serial, two-way
communications system that serves as a Local Area Network
(LAN) for factory/plant instrumentation and control devices.
The fieldbus environment is the base level group of the
digital networks in the hierarchy of plant networks. FOUNDATION
fieldbus is used in both process and manufacturing automation
applications and has a built-in capability to distribute
the control application across the network.
proprietary network protocols, FOUNDATION fieldbus is
neither owned by any individual company, or regulated
by a single nation or standards body. The technology is
controlled by the Fieldbus Foundation, a not-for-profit
organisation consisting of more than 100 of the world's
leading controls and instrumentation suppliers and end
While FOUNDATION fieldbus retains many of the desirable
features of the 4-20 mA analog system, such as a standardised
physical interface to the wire, bus-powered devices on
a single wire, and intrinsic safety options, it offers
a host of additional benefits to users.
With interoperability, one fieldbus device can be replaced
by a similar device with added functionality from a different
supplier on the same fieldbus network while maintaining
specified operations. This permits users to "mix and match"
field devices and host systems from various suppliers.
Individual fieldbus devices can also transmit and receive
multivariable information, and communicate directly with
each other over a common fieldbus, allowing new devices
to be added to the fieldbus without disrupting active
With FOUNDATION fieldbus, multiple variables from each
device can be brought into the plant control system for
archival, trend analysis, process optimization studies,
and report generation. This access to accurate, high resolution
data enables processes to be fine-tuned for better manufacturing
throughput and reduced plant downtime. These efficiencies
add up to higher plant performance and profitability.
Modern fieldbus devices, with powerful, microprocessor-based
communications capabilities, permit process errors to
be recognized faster, and with greater certainty. As a
result, plant operators are notified of abnormal conditions
or the need for preventive maintenance, and can make better
production decisions. Problems that detract from operating
efficiency are more quickly corrected, enabling yields
to go up while raw material costs and regulatory problems
Fieldbus technology will help manufacturing plants keep
up with increasingly stringent safety requirements. By
providing operators with earlier notification and warning
of pending and current hazardous conditions, fieldbus
allows for corrective action before an unplanned shutdown.
Enhanced plant diagnostic capabilities also reduce the
need for frequent access to hazardous areas, thus minimizing
the risks to field personnel.
Enhanced device diagnostics capabilities make it possible
to monitor and record such conditions as valve wear and
transmitter fouling. Plant personnel are able to perform
predictive maintenance without waiting for a scheduled
shutdown, thus avoiding or reducing downtime.
FOUNDATION Fieldbus' use of existing wiring and multi-drop
connections provides significant savings in network installation
costs. This includes reductions in intrinsic safety barrier
termination and cable costs, particularly in areas where
wiring is already in place.
Additional cost savings can be achieved through the decreased
time required for construction and start-up, as well as
simplified programming of control and logic functions
using software control blocks built into fieldbus devices.
Two related implementations of FOUNDATION fieldbus have
been introduced to meet different needs within the process
automation environment. These two implementations use
different physical media and communication speeds.
H1 works at 31.25 kbit/s and generally connects
to field devices. It provides communication and power
over standard twisted-pair wiring. H1 is currently the
most common implementation.
HSE (High-speed Ethernet) works at 100 Mbit/s
and generally connects input/output subsystems, host
systems, linking devices, gateways, and field devices
using standard Ethernet cabling. It doesn't currently
provide power over the cable, although work is under
way to address this.