Safety Considerations Guide, Tricon v9.0 - Tuv-fs.com

66 Sample Safety-Shutdown ProgramsPartitioned ProcessesYou can achieve greater system availability if you can allocate modules toprocesses that do not affect each other. For example, you could have two processeswith:• Outputs for one process on one DO module• Outputs for another process on a second DO module• Inputs from a shared DI module▼To partition processes:1 Partition the safety-critical I/O modules into three function blocks:• SHARED_IO for the shared safety-critical I/O modules.• PROCESS_1_IO for safety-critical I/O modules that do not affect process 2.• PROCESS_2_IO for safety-critical I/O modules that do not affect process 1.2 Connect the function blocks as shown in the EX03_SHUTDOWN example onpage 67.! CAUTIONThe EX03_SHUTDOWN sample program does not handle detected field faults,rare combinations of faults detected as field faults, or output voter faults hidden byfield faults. The application program, not the TR_SHUTDOWN function block,must read the NO_FLD_FLTS module status or FLD_OK point status to providethe required application-specific action.Tricon Safety Considerations Guide