Considerations When Saving Plc Data - Siemens SINUMERIK 840DiE sl Manual

15 User Data Backup/Standard Commissioning

15.3 Considerations when saving PLC data

15.3 Considerations when saving PLC data
Original image
Instantaneous
image
Inconsistent
image
15-464
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
The original image of the PLC is represented by the PLC data 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
If you cannot use the procedure described above, you can use the following
alternative procedure to save an original image:
Operating sequence:
1. Set the PLC to the operating status STOP
2. Archive PLC data
3. Set the PLC to the operating status RUN
An inconsistent image results if a series startup file with PLC data is created
and the PLC is in the status RUN (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.
Notice
The creation of a series–commissioning file with PLC data while the PLC is in
the RUN status (cyclic operation) may result in an inconsistent PLC image in
the series commissioning archive.
After this series startup file has been copied back, this data inconsistency in the
PLC user program may under certain circumstances result in the stop of the
PLC.
© Siemens AG 2007 All Rights Reserved
SINUMERIK 840Di sl Manual (HBIsl) – 01/2007 Edition
01/2007