Safety Integrated - Industry - Siemens

Program sequence
General overview
The following figure shows the program structure of both
S7-CPUs (S7-400 as DP Master and IM 151-7F-CPU as
DP Slave).
Transfer area in the I/O address space
For an intelligent DP Slave (here: IM 151-7F-CPU) the DP Master
does not access the connected inputs and outputs of the
intelligent DP slaves, but accesses a transfer area in the input/output
address space of the "preprocessing CPU". The input
addresses of the DP Master CPU (S7-400) are output addresses
of the DP Slave CPU (here: IM 151-7F-CP) and vice
versa.
Note
The configured I/O areas for data exchange between
master and slaves must not be "assigned" by I/O modules.
In this example, a transfer area of 32 bytes was reserved each
for inputs and outputs (from byte 14). You reach the mask be-
low as follows: In the hardware configuration of STEP 7 you
double-click the intelligent DP slave:
Note
All variables of the respective example, which are addressed
via the above described transfer area, start
their names with "C_" for "Couple" (e.g. C_OUT1).
Functional Example No. AS-FE-I-012-V10-EN 383
Ex. No.
12