IEC61511 edition 2 has undergone some changes since the original version. The standard has not changed in emphasis, although there have been some detail changes. There are no changes in scope or conformance requirements, although clause 3 does include both new and changed definitions.
In clauses 5 to 7, the main change is the emphasis on competence and functional safety assessment (FSA). A new security risk assessment requirement has been added to clause 8. There are clarified rules on the basic process control system as a protection layer, and more emphasis on software requirements.
The design phase now includes a specific requirement for a safety manual, and there are modified rules for hardware fault tolerance. The section on application programming has been completely re-written.
The primary change in the validation stage is the requirement to show traceability of all SIS documentation in the validation record.
Operationally, an SIS now requires both a specific operations procedure and maintenance plan. Users must also collect demand and failure data for reliability calculations.
So, what do these changes mean to users of the standard?
All end users must be aware of the new requirement for SIS and BPCS control system security assessment, probably implemented as part of the FSA. An SIS operations procedure and a maintenance plan will need to be developed, if not already in place. A database of failures and demands on the SIS will need to be developed.
For system integrators, or users who program their own logic solvers, there are new requirements to learn for specification and design of the application program. A checklist should be developed to ensure conformance with the new clause 12 of the standard, which is very different from original.
Due to the reference to sister standard IEC61508, suppliers of sensors, logic solvers and valves must consider updating any "SIL" certifications that pre-date 2010. All suppliers of devices with embedded software, operating systems and application programs must show evidence of product or system resilience to cyber-attacks.
This e-course is ideal for EC&I engineers, CFSP/CFSE, TUV FS Engineer, TUV FSCP's and other functional safety practitioners in the process industry sector.
The course assumes that subscribers have a reasonable existing level of knowledge of the original IEC 61511/ ISA 84 standard from 2004. Anyone who is new to the subject of IEC 61511 / ISA 61511 should start with the SIS Foundation course.
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