Siemens SIMATIC NET S7-300 Manual page 29

Configuring S7 Connections
Create S7 connections to use S7 communication for data exchange between two
SIMATIC S7 stations.
For more detailed information, refer to the STEP 7 Description /6/.
Notice
S7 connections via routers are supported only within a STEP 7 project but not
between partners in different STEP 7 projects of a multiproject!
Interface in the User Program of the S7 Station
You use SFBs (for S7-400) and FBs (for S7-300) in the user program.
SFB / FB12
SFB / FB13
SFB / FB15
SFB / FB14
SFB / FB8
SFB / FB9
SFC / FC62
1)
you do not need to configure a connection on the server
2)
for S7-300
Notice
Please remember the following points regarding data consistency in your user
program:
In the CPU of the S7 station, the read or written information is taken from the S7
user program into the operating system or copied from the operating system to the
S7 user program in blocks of 8 or 32 bytes (depending on the firmware version).
If information in the word or double-word format is located across such
boundaries, data inconsistency may arise during transmission using S7
communication!
For more detailed information, refer to the STEP 7 documentation /8/.
S7-CPs for Industrial Ethernet Configuring and Commissioning
Release 01/2007
C79000-G8976-C182-07
1 Communication via Ethernet CPs in S7 Stations
Block Type
BSEND
BRCV
PUT
GET
USEND
URCV
CONTROL (S7-400) /
C_CNTRL (S7-300)
Client Server
x - STEP 7
Documentation /8/ D
x
1)
x -
1)
x -
x -
- x
2)
x x
Described in
t ti /8/
A -29