Fieldbus and Sensor Validation.
Fieldbus is a generic term used to describe the set of standards now
emerging for digital communications in industrial plant. By providing
two-way transfer of data of arbitrary complexity, Fieldbus will
revolutionise industrial measurement and control practice, by making the
`intelligent' component the default. This development also offers challenges
to control and measurement theorists. The conventional models of sensors and
actuators - transmitters and receivers of single analogue signals - have
remained constant for decades. Fieldbus offers the opportunity to extend
these models, allowing components to describe their capabilities on-line
(ideally via generic metrics) so that truly optimal control, maintenance and
management decisions can be taken. Indeed there is an urgent need to provide
a solid theoretical framework to guide the current piecemeal efforts of
individual manufacturers.
The Sensor Validation (SEVA) programme at Oxford has been developing a theory
of how intelligent sensors should behave, working closely with Foxboro, one
of the leading control and instrumentation manufacturers. In addition to
generating a measurement, the SEVA sensor provides an uncertainty estimate
and generic status information. A number of prototype systems have been
developed, based upon commercial instruments.
This talk will describe the SEVA concepts (hopefully including a
video), and suggest corresponding definitions for the
self-validating actuator. In addition, some consideration will be given to
how control algorithms may be extended to make use of the additional data
provided by these devices.
Dr Manus Henry,
Oxford University