Modification Of The Hardware Configuration; Modifications To The User Program And The Connection Configuration - Siemens SIMATIC S7-400H Manual

Modifying the System During Operation
• PROFIBUS DP and PROFIBUS PA LAN cables are to be equipped with active
bus terminators at both ends so that the lines continue to be correctly
terminated during the modification work.
• PROFIBUS PA bus systems should be built up using components from the
SpliTConnect product range (see interactive catalog CA01) so that separation
of the lines is not required.
• Loaded data blocks must not be deleted and created again. In other words,
SFCs 22 (CREATE_DB) and 23 (DEL_DB) may not be applied to DB numbers
occupied by loaded DBs.
• Make sure that at the time the system modification is made on the PG/ES the
current status of the user program is still available as a STEP 7 project in
modular form. It is not sufficient for the user program from one of the CPUs to
be loaded back into the PG/ES or compiled again from a STL source file.

Modification of the hardware configuration

With a few exceptions, all segments of the configuration can be modified during
operation. As a rule, a configuration modification also results in a modification in
the user program.
The following must not be modified:
• certain CPU parameters (for details refer to the relevant subsections)
• the transmission rate (baud rate) of redundant DP master systems
• S7 and S7H connections

Modifications to the user program and the connection configuration

The modifications to the user program and the connection configuration are loaded
into the PLC in redundant system mode. The procedure depends on the software
used. For more details refer to the Programming with STEP 7 V5.1 manual and the
PCS 7, Configuration Manual.
Special Features
• Do not carry out more modifications than you can keep an overview of. We
recommend that you modify only one DP master and/or a few DP slaves (e.g.
no more than 5) per reconfiguration run.
• During routine operation, you can add or remove modules in DP stations with a
redundant PROFIBUS-DP interface module only with the interface modules
IM 153-2, IM 153-2FO or IM 157 specified in Section 7.3.
• In the case of IM 153-2 bus modules can only be plugged in is the power supply
is interrupted.
• Before making a change, check the fault tolerance parameter in HW Config. If
this parameter is set to 0, have the parameter calculated again in HW Config
using the Properties CPU –> H Parameter.
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Automation System S7-400H Fault-tolerant Systems
A5E00068197-07