When Cat. 4/SIL 3 is required, the isolation module must be implemented in the following situations:
Application | Isolation module must be used |
Central use after CPU 31xF-2 DP or CPU 31xF-2 PN/DP | |
| Yes, behind the CPU |
| Yes, after the last standard module and before the first fail-safe module |
Central use after CPU 31xF-2 DP or CPU 31xF-2 PN/DP in an expansion rack | |
| Yes, after the IM 36x |
| Yes, after the last standard module and before the first fail-safe module |
Distributed behind the IM 153-2 with copper connection | |
| Yes, after the IM 153-2 |
| Yes, after the last standard module and before the first fail-safe module |
Distributed behind the IM 153-2 with fiber-optic connection | |
| No |
| Yes, after the last standard module and before the first fail-safe module |