Intermediate Memory In The Cpu 41X As Dp Slave - Siemens SIMATIC S7-400 Reference Manual

Monitor/Modify, Programming via PROFIBUS
As an alternative to the MPI interface, you can use the PROFIBUS DP interface to
program the CPU or execute the programming device functions Monitor and
Modify. To do this, you must enable these functions when you configure the CPU
as DP slave in STEP 7.
Note
The use of Programming or Monitor and Modify via the PROFIBUS DP interface
extends the DP cycle.
Data Transfer Via an Intermediate Memory
As a DP slave the CPU 41x makes an intermediate memory available to
PROFIBUS DP. Data transfer between the CPU as DP slave and the DP master
always takes place via this intermediate memory. You can configure up to
32 address areas for this.
In other words, the DP master writes its data in these address areas of the
intermediate memory and the CPU reads the data in the user program and vice
versa.
DP master
PROFIBUS
Figure 1-11

Intermediate Memory in the CPU 41x as DP Slave

Automation System S7-400 CPU Specifications
A5E00165965-01
CPU 41x as DP slave
Intermediate
I/O
memory in the I/O
address area
Structure of a CPU 41x
I/O
1-47