Step 1: Application Program Safety Requirements
Objective:
- To specify application program safety requirements for each SIS necessary to implement the required SIF.
- To specify the requirements for the application program for each SIF allocated to that SIS.
Inputs:
- SIS safety requirements
- Safety manuals of the selected SIS
- SIS architecture
Outputs:
- SIS application program safety requirements specification
- Verification information
Step 2: Application Program Safety Validation Planning
Objective:
To develop a plan for validating the application program.
Inputs:
- SIS application program safety requirements
Outputs:
- SIS safety validation planning
- Verification information
Step 3: Application Program Development Architecture
Objective:
- To create an application program architecture that fulfills the specified requirements for application program safety.
- To review and evaluate the requirements placed on the application program by the hardware architecture of the SIS.
- To specify the procedures for the development of the application program.
Inputs:
- SIS application program safety requirements
- SIS hardware architecture design constraints
Outputs:
- Description of the architecture design (e.g., segregation of application program into related process subsystems and SIL recognition of common modules like pump or valve sequences)
- Application program architecture and subsystem integration test requirements
- Verification information
Step 4: Application Program Design
Objective:
- To develop the application program design.
- To identify a suitable set of configuration, library, management, and simulation/test tools over the safety life cycle of the application program.
Inputs:
- SIS application program safety requirements
- Description of the architecture design
- Manuals of the SIS
- Safety manual of the selected SIS logic solver
Outputs:
- Application program design
- Procedures for use during programming
- Description of the standard (manufacturer’s) library functions to be used
- Verification information
Step 5: Application Program Implementation
Objective:
- Application development and application module development.
- To implement the application program that fulfills the specified requirements for application safety.
- To use appropriate support tools and programming languages.
Inputs:
- Description of the design
- List of manuals and procedures of the selected logic solver
Outputs:
- Application program (e.g., function block diagrams, ladder logic)
- Application program simulation and integration test
- Special-purpose application program safety requirements
- Verification information
Step 6: Application Program Verification
Objective:
- To verify that the requirements for application program safety have been achieved.
- To show that all SIS application programs interact correctly to perform their intended functions and do not perform unintended functions.
Inputs:
- Application program simulation and integration test requirements (structure-based testing)
- Application program architecture integration test requirements
Outputs:
- Application program test results
- Verified and tested application program system
- Verification information
Step 7: SIS Integration Test
Objective:
- To integrate the application program onto the target logic solver, including interaction with a sample set of field devices and/or simulator.
Inputs:
- Application program and logic solver integration test requirements
Outputs:
- Application program and logic solver integration test results
