Siemens SIMATIC S7-1500 System Manual page 366

Please also note the following FAQs on the Internet
(https://support.industry.siemens.com/cs/ww/en/view/59457183) for removal of the SIMATIC
memory card.
Note
If you switch a CPU in redundant mode to the STOP operating state, the S7-1500R/H
redundant system switches to the RUN-Solo system state. The other CPU maintains control of
the process.
CPU response after a SIMATIC memory card is removed or inserted
Inserting or removing the SIMATIC memory card in STOP operating state triggers a re-
evaluation of the SIMATIC memory card. The CPU compares the content of the configuration
on the SIMATIC memory card with the backed-up retentive data. If the backed-up retentive
data matches the data of the configuration on the SIMATIC memory card, the retentive data
is retained. If the data differs, the CPU automatically performs a memory reset. A memory
reset deletes the retentive data on the CPU. You can find more information on memory resets
in the section CPU memory reset (Page 417).
The CPU evaluates the SIMATIC memory card. This process is indicated by the RUN/STOP LED
flashing.
Note
Using the SIMATIC memory card as a firmware update card
If you use the SIMATIC memory card as a firmware update card, pulling and plugging the card
will not result in the loss of retentive data.
Reference
You can find more information on the SIMATIC memory card in the function manual Structure
and use of the CPU memory
(https://support.industry.siemens.com/cs/ww/en/view/59193101).
S7-1500R/H redundant system
System Manual, 01/2024, A5E41814787-AF
Commissioning
12.3 Commissioning procedure
365