Step 7, Step I: Offline Modification Of The Hardware Configuration; Step 7, Step Ii: Editing And Downloading The User Program - Siemens SIMATIC S7-400H System Manual

System modifications in operation
14.6 Removing components in STEP 7
14.6.1

STEP 7, step I: Offline modification of the hardware configuration

Starting situation
The fault-tolerant system is operating in redundant mode.
Procedure
1. Perform all the modifications to the hardware configuration relating to the hardware being
2. Compile the new hardware configuration, but do not load it into the PLC just yet.
Result
The modified hardware configuration is in the PG. The PLC continues operation with the old
configuration in redundant mode.
14.6.2

STEP 7, step II: Editing and downloading the user program

Starting situation
The fault-tolerant system is operating in redundant mode.
Restrictions
Any attempts to modify the structure of an FB interface or the instance data of an FB in
redundant mode will lead to a system STOP at both CPUs.
Procedure
1. Edit only the program elements related to the hardware removal.
2. Download only the program changes to the PLC.
Result
The fault-tolerant system is operating in redundant mode. The new user program will no
longer attempt to access the hardware being removed.
228
removed offline.
CAUTION
You can add, edit or remove OBs, FBs, FCs and DBs.
System Manual, 09/2007, A5E00267695-03
S7-400H