Siemens SIMATIC ET 200M Operating Instructions Manual page 161

• In redundant mode the function SYNC / FREEZE is not activated.
Note
If the function SYNC / FREEZE is nevertheless activated in a redundant system, the user
bears the responsibility for the behavior of the H system (e.g. when changing over).
• In a redundant system, you can only use the IM 153-2 interface module on DP masters
that support the "fail safe" parameter. The IM 153-2 will not run on DP masters that do not
support this parameter, and the BF LED flashes.
Tip: You can see in the GSD-file of the DP master whether this "fail safe" is supported.
Example configuration of a redundant DP master system and IM 153-2
The following figure shows an example configuration on an S7-400H. For the S7-400H the ET
200M is a one-channel switched (distributed) I/O. For detailed assembly instructions for H
systems, refer to the"S7-400H automation system, fault-tolerant systems
(https://support.automation.siemens.com/WW/view/en/1186523)" manual.
Figure 8-20
①
②
③
ET 200M
Operating Instructions, 04/2022, EWA-4NEB7806006-09
Redundancy with 2 x IM 153-2 in an H system
S7-400H automation system
ET 200M distributed I/O with 2 x IM 153-2
redundant DP master system
Functions
8.4 Redundancy with IM 153-2
161