Siemens SIMATIC S7-400 Manual page 26

Structure of a CPU 41x
2.5 Running a memory reset
Values Retained After a Memory Reset
After the CPU has been reset, the following values remain:
● The content of the diagnostic buffer
● Parameters of the MPI (MPI address and highest MPI address). Note the special features
● The IP address of the CPU
● The subnet mask
● The SNMP parameters
● The time of day
● The status and value of the operating hours counter
Special Features MPI parameters and IP address
A special situation is presented for the MPI parameters and IP address when a CPU memory
reset is preformed. The following table shows which MPI parameters and IP address remain
valid after a CPU memory reset.
Table 2-10
With inserted FLASH card
Without plugged FLASH card
2-14
The content can be read out with the programming device using STEP 7.
shown in the table below.
MPI parameters and IP address following memory reset
Memory reset .. MPI parameters and IP address ...
..., stored on the FLASH card are valid
...are retained in the CPU and valid
S7-400 Automation System, CPU Specifications
Manual, 10/2006, 6ES7498-8AA04-8BA0