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Institute of Measurement and Control. Functional Safety 2016
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Integrated 2 Zone
Figure 5 Integrated 2 Zone
In the Integrated architecture the BPCS and SIS are typically from the same vendor and are
networked together but utilize physically separate controllers. The level of integration differs from
one vendor offering to another but will typically have extensive commonality of hardware,
engineering tools, engineering workstations and operator interface. A truly integrated system will
have been designed to take into account common cause failures and will also factor in the need for
security.
Such systems take advantage of certified safety communications which provide a safe and secure
method for connectivity thus enabling owner/operators to reduce costs and improve overall
operational efficiency. An example of this would be certified safety communications from the
Operator Interface to the SIS for bypasses, maintenance overrides etc, and safety communications
between controllers.
BPCS and SIS controllers are, in most cases, physically separate even in an integrated system they
can be effectively separated into independent zones and conduits with the potential for achieving
the necessary security. For new systems vendor guidelines should show how the requirements of
the standards can be met. Retrospectively applying this for existing systems may prove more
challenging but is still quite possible.