The two hardware types are different, and their physical installation and configuration in DeltaV Explorer is different, but both provide similar functionality to implement safety instrumented systems. The differences are explained in other sections of this document. The term logic solver applies to both systems and is used when information being discussed applies to both systems.
DeltaV SIS components are physically separate from, but integrated with, the DeltaV distributed control system (also known as a basic process control system or BPCS). The logic solvers execute SIS modules that perform the safety instrumented function. Safety instrumented functions are configured in one or more SIS modules using the DeltaV engineering tools—DeltaV Explorer and Control Studio.
Configuration and use of SIS modules are similar in both systems. The main difference is in the system capacities of the two systems. Any differences are explained in this document when necessary.
In some cases the SIF cannot be completely implemented in a single module, so data must be shared between SIS modules. This data is shared through the use of Secure Parameters and Secure Parameter References. Secure Parameters can be Boolean or non-Boolean. They have status values that the SIS module can write to, and they can be referenced by other SIS modules. The number of secure parameters and the scope in which they can be referenced depend on the SIS implementation.