724 / 1145
Institute of Measurement and Control. Functional Safety 2016
Page 12
Common or Integrated 1 Zone
Figure 6 Integrated 1 Zone
In a common architecture the BPCS and SIS are on a common platform and the functionality is
combined into a single controller. There is commonality of hardware, engineering tools and operator
interface. Standard and safety-related programs are executed in parallel and independent of each
other. This approach offers lower hardware costs and the need for fewer spare parts.
Common architectures can take advantage of the some of the same techniques as those used in an
integrated system to achieve separation of control and safety but, with the BPCS and SIS
functionality in the same physical device, there is little scope for considering them as separate zones
from a security standpoint. This makes achieving security more challenging but it can still be an
option, particularly if the risk from cyber threats is less. Again vendor’s guidelines indicate how the
requirements of the standards can be met for this type of architecture.