Pcs 7, Step Ii: Editing And Downloading The User Program - Siemens SIMATIC S7-400H System Manual

14.4.2

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

Starting situation
The fault-tolerant system is operating in redundant mode.
The following program modifications are not possible in redundant state and result in the
system mode Stop (both CPUs in STOP mode):
• Structural modifications to an FB interface or the FB instance data.
• Structural modifications to global DBs.
• Compression of the CFC user program.
Before the entire program is recompiled and reloaded due to such modifications the
parameter values must be read back into the CFC, otherwise the modifications to the block
parameters could be lost. You will find more detailed information on this topic in the
CFC for S7, Continuous Function Chart
Procedure
1. Only make program changes related to the hardware you are removing. You can delete
2. In SIMATIC Manager, select the charts folder and choose the "Options > Charts >
3. Compile only the modifications in the charts and download them to the PLC.
Result
The fault-tolerant system continues to operate in redundant mode. The modified user program
will no longer attempt to access the hardware being removed.
S7-400H
System Manual, 09/2007, A5E00267695-03
CAUTION
the following components:
– CFC and SFC charts
– Blocks in existing charts
– Channel drivers, interconnections and parameter settings
Generate Module Drivers" menu command.
This removes the driver blocks that are no longer required.
NOTICE
Until an FC is called the first time, the value of its output is undefined. This must be taken
into account in the interconnection of the FC outputs.
System modifications in operation
14.4 Removing components in PCS 7
manual.
213