Rockwell Automation AADvance Controller Solutions Handbook - Manual (Page 53)

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Document: 553631
(ICSTT-RM447J_EN_P) Issue: 09:
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SIL2 Fault Tolerant Input Architectures
A SIL2 fault tolerant input architecture can have dual or triple input modules with a
single processor and single output modules. The illustration shows a dual input
arrangement where the dual input modules operate in 1oo2D under no fault
conditions, they degrade to 1oo1D on detection of the first fault in either module of
the redundant pair, and when a fault occurs on the second module it will fail-safe.
The processor module operates in 1oo1D under no fault conditions and degrades to
fail safe on the first detected fault. The output module operates in 1oo1D under no
fault conditions and will fail-safe on the first detected fault.
When a triple input module arrangement is configured the group of input modules
operate in 2oo3D under no fault conditions, degrade to 1oo2D on the detection of
first fault in any module, then degrade to 1oo1D on the detection of faults in any two
modules, and will fail-safe when there are faults on all three modules.
Table 6: Modules for SIL2 Architecture
Position Module Type
I/P A and B 2 × T9401/2 Digital Input Module, 24V dc, 8/16 Channel +
T9802 Digital Input TA, 16 Channel, Dual or 2 × T9431/2
Analogue Input Module, 8/16 Channel, Isolated, + T9832
Analogue Input TA, 16 Channel, Dual
T9300 I/O Base Unit
CPU A 1 x T9110 Processor Module, T9100 Base Unit
O/P A T9451 Digital Output Module, 24V dc, 8 Channel +
T9851 Digital Output TA, 24V dc, 8 Channel, Simplex
T9300 I/O Base Unit