This year Emerson Process Management introduced an innovative safety solution that is the first Safety Integrated System that integrates the logic solver with the diagnostics included in intelligent field devices to minimize the hazards associated with periodic manual checks of final sensing and control elements in the safety loop. The Emerson approach continuously diagnoses the sensors, logic solver, and final control elements as an entity to perform on demand as required. What''s more, Emerson has integrated the operations, maintenance, and engineering environments of the Safety Instrumented System (SIS) and the basic process control system (BPCS), which ensures that the information from the intelligent field devices can be automatically routed to the right personnel in real time.
The Offshore Reliability Database shows that 92% of the failures in safety loops arise from difficulties in the sensors (42%) and final control elements (50%.) The Emerson approach uses the intelligence in these digital devices to monitor and alert maintenance personnel and operators to possible difficulties. In addition, it is possible to replace some, or all, of the periodic manual testing of final control elements with automated partial valve stroke testing. This improves the performance of the safety loop, while reducing or eliminating the chance for human errors that occur during manual valve testing and simultaneously increasing the time between plant shutdowns.
The Emerson Safety System is rated suitable for use in for SIL 1-3-rated safety applications, as defined by the stringent international standard IEC 61508 for Functional Safety. It has also includes tools to automate compliance with the IEC 61511 standard, easing the burden on the plant owner / operator.
The SIS is engineered to work seamlessly with the basic process control system. All required separations of engineering tools, operating systems, and communications are maintained to ensure the integrity of the safety applications. At the same time information from the safety instrumented system can be presented to operators and the configuration of the system can be done using the same tools as those used for the basic process control system.
For the first time, the logic solver portion of the safety instrumented system is available in small modules with 16 I/O channels built in. This gives engineers the flexibility to purchase only the amount of safety loops they need for their facilities and distribute the logic solvers in the facility to reduce installation and wiring costs.
Finally, the safety instrumented system was designed with OLE for Process Control (OPC) integration to other industrial systems and applications including MES applications. The safety instrumented system can easily send system data, alarms, and events to plantwide historians and MES applications to facilitate system maintenance.