Siemens SIMATIC PCS 7 Function Manual page 173

Use cases for plant changes
A plant change in which the hardware of the plant is changes occurs in the following cases:
● Hardware components of a fault-tolerant system are removed.
● Hardware components of a fault-tolerant system are added.
● Hardware components of a fault-tolerant system are replaced by non-identical components.
Plant modification always requires a software modification. Configuration changes are made
in HW Config and downloaded to the CPU. The modified hardware is physically replaced,
removed or added.
Similar to the events that occur when components are replaced, when the system is modified
in runtime, the functions of the modified components are taken over by the corresponding
redundant components. The running program is not interrupted.
Which components can be changed?
changes
Changes in the CPU
Adding for removing modules in central
racks
Adding or removing modules
components in distributed I/O modules
Changing the parameters settings for a
module
Fault-tolerant Process Control Systems (V8.0)
Function Manual, 03/2012, A5E02779471-02
Component Replacement and Plant Changes
Possible modifications
● Editing CPU Parameters
● Changes to the memory components of the CPU
● Communication modules
● Interface modules (for example, IM 460, IM 461), in de-
energized state only
● DP slaves with redundant interface modules (for
example, ET 200M, DP/PA Link, Y Link)
● Non-redundant DP slaves in any DP master system
● Modules in modular DP slaves
● DP/PA Coupler
● PA devices (process automation)
● Use of a free channel or reassignment of a utilized
channel on an existing module
● Editing parameters
5.2 Plant changes in runtime
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