11 Data Backup
11.10 Saving PLC data
11.9
Machine/Setting data
11.10
Saving PLC data
Original image of
project
Instantaneous
image of PLC–CPU
11-284
The machine/setting data are listed in
References:
/LIS/ Lists
The consistency of the PLC data backup can only be guaranteed if the proce-
dure below is followed:
1. Switch PLC to PLC–STOP (PLC switch S4 to position 2)
2. Transfer the PLC data from the programmer to the control
3. Archive the PLC data
4. Switch the PLC to PLC–RUN (PLC switch S4 to position 0)
This sequence of operations produces an original image of the project in the
data backup.
As an alternative to the above, the PLC can be switched from PLC–RUN to
PLC–STOP:
1. Switch PLC to PLC–STOP (PLC switch S4 to position 2)
2. Archive the PLC data
3. Switch the PLC to PLC–RUN (PLC switch S4 to position 0)
This sequence of operations produces an instantaneous image of the PLC–
CPU contents in the data backup.
Note
If the PLC data backup is performed during cyclic operation of the PLC (PLC–
RUN), the data modules are not backed up at the same time. This may result in
a data inconsistency which causes the user program to stop the PLC.
SINUMERIK 840D Installation and Start-Up Guide (IAD) – 04.00 Edition
Siemens AG 2000 All Rights Reserved
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