Considerations When Backing Up Plc Data - Siemens SINUMERIK 840Di sl Commissioning Manual

15.3

Considerations when backing up PLC data

When creating a series startup file that contains PLC data, the PLC image that is saved
during this process is dependent on the status of the PLC at the time of creation.
Depending on the status of the PLC, the following PLC images result:
● Original image
● Instantaneous image
● Inconsistent image
Original image
The original image of the PLC is represented by the PLC-data state immediately after
loading the S7 project into the PLC.
Operating sequence:
1. Set the PLC to the operating status STOP
2. Load the appropriate S7 project into the PLC using the SIMATIC Manager STEP 7
3. Create a series startup file with PLC data
4. Set the PLC to the operating status RUN
Instantaneous image
If you cannot create an original image, you can save an instantaneous image as an
alternative.
Operating sequence:
1. Set the PLC to the operating status STOP
2. Archive PLC data
3. Set the PLC to the operating status RUN
Inconsistent image
An inconsistent image results if a series-commissioning file with PLC data is created and the
PLC is in the RUN state (cyclic operation).
The data blocks of the PLC are saved at different times with contents that under certain
circumstances may meanwhile have changed. This may result in a data inconsistency that
after copying the data backup back into the PLC may under certain circumstances result in
PLC stop in the user program.
Manual
Commissioning Manual, 05/2008, 6FC5397–4CP10–4BA0
User data backup/Series commissioning
15.3 Considerations when backing up PLC data
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