Siemens SIMATIC S7-1200

Programming concepts
7.8 Synchronizing the online CPU and offline project
S7-1200 Programmable controller
System Manual, V4.2, 09/2016, A5E02486680-AK
219
See also
Synchronizing the online CPU and offline project (Page 219)
7.8
Synchronizing the online CPU and offline project
When you download project blocks to the CPU, the CPU can detect whether blocks or tags
have changed in the online CPU since the last download. In such cases, the CPU offers you
the choice to synchronize the changes. This means that you can upload the online CPU
changes to the project before downloading the project to the CPU. Changes in the online
CPU can be due to a variety of factors:
● Changes to the start values of data block tags during runtime, for example by the
WRIT_DBL instruction (Page 538) or by loading a recipe
● A download from a "secondary" project (a project other than the one that originated the
last download) where one or more of the following conditions exist:
– The online CPU includes program blocks that do not exist in the project.
– Data block tags or block attributes differ between the offline project and online CPU.
– PLC tags exist in the online CPU that do not exist in the offline project.
Note
If you edit blocks or tags in the project that you used for the last download, you do not have
to make any choices about synchronization. STEP 7 and the CPU detect that the offline
project changes are newer than the o
nline CPU and proceeds with a normal download
operation.