Specific Blocks For S7-400H - Siemens SIMATIC S7-400H Manual

S7-400H Installation Options

Specific Blocks for S7-400H

Apart from the blocks that can be used on both the S7-400 and the S7-400H, there
are further additional blocks for the S7-400H with which you can influence the
redundancy functions.
You can react to redundancy errors of the S7-400H with the following organization
blocks:
• OB 70, I/O redundancy errors
• OB 72, CPU redundancy errors
Using the system function SFC 90 "H_CTRL" you can disable and re-enable
link-up and updating of the fault-tolerant CPUs. You can also affect the scope and
routine of the cyclic self–test.
Notice
With a fail-safe system, the periodic self-tests must not be inhibited and then
enabled again.
For more details refer to the manual S7-400F and S7-400FH Programmable
Controllers.
Further information
You will find detailed information on the programming of the above-mentioned
blocks in the manual called Programming with STEP 7 and in the Reference
Manual called System Software for S7-300/400, System and Standard Functions.
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Automation System S7-400H Fault-tolerant Systems
A5E00068197-07