AADvance Safety Manual - Tuv-fs.com

Chapter 4 AADvance System ArchitecturesSIL2 Fault Tolerant Input ArchitecturesA SIL2 fault tolerant input architecture can have dual or triple input modules with asingle processor and a single output module.The illustration shows a dual input arrangement where the dual input modules operatein 1oo2D under no fault conditions, they degrade to 1oo1D on detection of the firstfault in either module of the redundant pair, and when a fault occurs on the secondmodule it will fail-safe.The processor module operates in 1oo1D under no fault conditions and degrades tofail safe on the first detected fault. The output module operates in 1oo1D under nofault conditions and will fail-safe on the first detected fault.When a triple input module arrangement is configured the group of input modulesoperate in 2oo3D under no fault conditions, degrade to 1oo2D on the detection offirst fault in any module, then degrade to 1oo1D on the detection of faults in any twomodules, and will fail-safe when there are faults on all three modules.Table 3:Modules for SIL2 ArchitecturePositionModule TypeI/P A and B 2 × 9401/2 Digital Input Module, 24V dc, 8/16 Channel +9802 Digital Input TA, 16 Channel, Dual or 2 × 9431/2Analogue Input Module, 8/16 Channel, Isolated, + 9832Analogue Input TA, 16 Channel, DualCPU A1 x 9110 Processor Module, 9100 Base Unit and 9300 I/OBase UnitO/P A 9451 Digital Output Module, 24V dc, 8 Channel +9851 Digital Output TA, 24V dc, 8 Channel, SimplexDocument number 553630 Issue 7: February 2010 4-3