Update Sequence - Siemens SIMATIC CPU 410 System Manual

If 3. is inconsistent, the user program in the load memory in RAM is copied from the master
CPU to the standby CPU.
Link-up with master/standby changeover
In STEP 7 you can select one of the following options:
● "Switch to CPU with modified configuration"
● "Switchover to CPU with modified operating system"
● "Switchover to CPU with modified hardware version"
● "Switchover to CPU via only one intact redundant link"
● "Switching to a CPU with modified PO limit"
Switch to CPU with modified configuration
You may have modified the following elements on the standby CPU:
● The hardware configuration
No blocks are transferred from the master to the standby during the link-up. The exact
circumstances are described in Chapter Switch to CPU with modified configuration
(Page 351).
For information on steps required in the scenarios mentioned above, refer to section
Replacement of failed components during redundant operation (Page 223).
Note
Even though you have not modified the hardware configuration on the standby CPU, there is
nevertheless a master/standby changeover and the previous master CPU switches to STOP.
18.13.2

Update sequence

What happens during updating?
The execution of communication functions and OBs is restricted section by section during
updating. Likewise, all the dynamic data (content of the data blocks, timers, counters, and bit
memories) are transferred to the standby CPU.
Update procedure:
1. Until the update is completed, all asynchronous SFCs and SFBs which access data
records of I/O modules (SFCs 13, 51, 52, 53, 55 to 59, SFB 52 and 53) are
acknowledged as "negative" with the return values W#16#80C3 (SFCs 13, 55 to 59, SFB
52 and 53) or W#16#8085 (SFC 51). When these values are returned, the jobs should be
repeated by the user program.
2. Message functions are delayed until the update is completed (see list below).
CPU 410 Process Automation/CPU 410 SMART
System Manual, 05/2017, A5E31622160-AC
Supplementary information
18.13 Link-up and update sequence
347