The DeltaV SIS™ unique, modular distributed architecture enables customization for each SIS application. Whether you have an isolated boiler or a large ESD application, the DeltaV SIS system scales to help provide the safety coverage you require for your SIL 1, 2 and 3 applications. Modularity gives you the flexibility to meet changing project requirements. The DeltaV SIS architecture is flexible to help provide the safety you want, when you want, where you want.
Unlike other approaches, the modular logic solver hardware scales in sizes of 16 configurable I/O. This means memory and logic solver processing is automatically added with increasing I/O count. The days of running out of memory or processing power are over. Furthermore, a capacity limit of 30,000 I/O provides flexibility and confidence that the DeltaV SIS system can be designed to fit the needs of large processes.
The DeltaV SIS logic solver also provides flexible redundancy. That means redundant logic solvers can be used only where availability is highly critical. Simplex logic solvers can be specified where availability is not as critical and be on the same node as the redundant logic solvers. Implementation of both simplex and redundant logic solvers have been certified by TÜV as SIL 3 rated.
The DeltaV SIS architecture allows you to concentrate on the design of each safety instrumented function (SIF). Each logic solver is a container for a small number of SIFs, and there can be no unplanned interaction between them. This is very different from the traditional approach where hundreds of SIFs are all placed in a single safety PLC and the effect of changing a single register or the addition of a SIF could affect all of the logic. This architecture isolates SIFs, which eliminates single points of failure and simplifies change management. For complex applications, which require multiple SIFs acting on the same final element, input data is shared among multiple logic solvers so that cause and effect logic can easily be implemented in a single SIS module.
Multiple DeltaV SIS nodes can be connected together via the SISNet secure communications network. The SISNet is a redundant counter-rotating fiber optic ring network that provides SIL 3 certified communications between DeltaV SIS nodes with very high communications reliability. The SISNet can provide the capability to distribute safety logic throughout a facility, installing just the right amount of logic solving where it is needed. The SISNet provides increased flexibility to implement megaprojects, as well as providing easier expansion of existing systems.
