Technical Notes
TÜV grants concept approval
for safety fieldbus system
ISA News, February
18, 2004.
Independent testing agency
TÜV approved the Fieldbus Foundation's Safety Instrumented
Systems (FF-SIS) system concept. This move now allows
for the validation of the FF-SIS technical specifications
this year. Fieldbus foundation is developing specifications
and guidelines that meetthe International Electrotechnical
Commission (IEC) 61508 standard (functional safety of
electrical/electronic /programmable electronic safety-related
systems), and IEC 61511 (functional safety: safety instrumented
systems for the process industry sector). IEC 61511
addresses the application of safety instrumented systems.
"The specifications will
enable instrumentation suppliers to build a widerange
of devices that comply with IEC 61508," said David
A. Glanzer, Fieldbus Foundation director of technology
development. "Third-party certifiers, such as TÜV,
will certify the safety integrity level (SIL) capability
of the instruments based on this standard. In addition,
end users will evaluate the requirements for their safety
instrumented systems according to the IEC 61511 standard."
Senior technologists and end users from foundation member
companies collaborated on the FF-SIS project plan and
developed a system architecture and draft specifications
to meet the TÜV requirements.
Companies on the FF-SIS development team include: ABB,
DuPont, Emerson Process Management, ExxonMobil, HIMA,
Honeywell, Invensys/Triconex, Metso Automation, Rockwell
Automation, Rotork Control Systems, Saudi Aramco, Shell
Global Solutions, Smar, Softing, TÜV and Yokogawa.
To meet the requirements of the IEC 61508 standard,
FF-SIS specifies a special protocol layer between the
standard fieldbus communications and the function block
application process. The special layer adds error checking
to ensure that if a device malfunctions and sends out
a bad message, the system detects the bad message and
takes the proper action. For related information, go
to www.isa.org/networks.
