Siemens S7-1200 Programming Manualline page 37

3 General Programming
3.2 Program blocks
Figure 3-13: Downloading without reinitialization
Block in
the controller
Name
Tag1
Tag2
Tag3
Execute the following steps whilst the controller is in RUN mode.
1. Enable "Downloading without reinitialization"
2. Insert new defined tags in existing block
3. Load block into controller
Advantages
Reloading of new defined tags without interrupting the running process. The
controller stays in "RUN" mode.
Properties
Downloading without reinitialization is only possible for optimized blocks.
New defined tags will be initialized. The remaining tags keep their current
values.
A block with reserve requires more memory space in the controller.
The memory reserve depends on the work memory of the controller; however it
is max. 2 MB.
It is assumed that a memory reserve has been defined for block.
By default the memory reserve is set to 100 byte.
The memory reserve is defined individually for every block.
The blocks can be variably expanded.
Recommendation
Define a memory reserve for blocks that are to be expanded during
commissioning (e.g. test blocks). The commissioning process is not interrupted
by download of new defined tags. The current values of already existing
variables are kept.
Programming Guideline for S7-1200/1500
V1.2, Entry ID: 81318674
Block
in project
Value Name
1
3.4 Tag1
451 Tag2
23 Tag3
Tag4
Tag5
2
Block in
the controller
Name
Value
Tag1 3.4
Tag2 451
3
Tag3 23
Tag4 0
Tag5 0
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