3.18.2
Redundancy with S7 DP Masters
Principle of operation
Redundancy on an H-system provides the highest availability. If an interface module fails, the
system switches over to the redundant interface module without interruption.
Prerequisites
● H-system (e.g. S7-400H)
● Terminal module TM-IM/IM
● 2 x IM 152 (V2.0 and higher)
● 2 x RS 485-IS coupler
●
STEP 7 software package and SIMATIC S7 H systems
● In a redundant system, the IM 152 can only be implemented on DP masters that support
the "Fail-Safe" parameter. On DP masters that do not support this parameter, the IM 152
does not start up, and the BF LED flashes.
Tip: The GSD file of the DP master indicates whether it supports this "Fail-Safe" parameter.
WARNING
The SYNC/FREEZE function must not be activated during redundant operation. Violation
of this condition can result in invalid process values.
Cross-segment synchronization of SYNC/FREEZE commands does not take place during
redundant operation.
Installation and wiring
The H-system is completely set up, configured, and parameterized.
1. Install the ET 200iSP with terminal module TM-IM/IM.
2. Connect a PROFIBUS RS 485-IS to each bus connector. Each PROFIBUS RS 485-IS
requires a separate RS 485-IS coupler.
3. Fit the TM-IM/IM with two IM 152 interface modules (V2.0 or higher).
Configuration and parameter assignment
1. In the "Hardware Catalog" of HW Config, select a suitable DP master interface and place
it in both module racks. In the properties dialog that appears automatically, create
PROFIBUS DP networks with the same parameters for both DP master interfaces.
2. For each DP master system, insert a DP master system. Result: STEP 7 will automatically
produce a redundant system.
3. Drag one IM 152 (V2.0 and higher) from the "Hardware Catalog" to a PROFIBUS DP in the
station window. Result: STEP 7 will automatically create the connection to both PROFIBUS
DPs.
Configuration options
3.18 Redundancy with IM 152
ET 200iSP
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Operating Instructions, 11/2017, A5E00247483-07