Safety Considerations Guide for Triconex General ... - ICEWeb

Sample Safety-Shutdown Programs 57
Partitioned Processes
You can achieve greater system availability if you can allocate modules to processes that do not
affect each other. For example, you could have two processes with:
• Outputs for one process on one DO module
• Outputs for another process on a second DO module
• Inputs from a shared DI module
You do this by partitioning processes.
Procedure
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 on page 58.
CAUTION
EX03_SHUTDOWN does not handle detected field faults, rare
combinations of faults detected as field faults, or output voter faults
hidden by field faults. The application, not the SYS_SHUTDOWN
function block, must read the NO_FLD_FLTS module status or FLD_OK
point status to provide the required application-specific action.
Safety Considerations Guide for Triconex General Purpose v2 Systems