Siemens S7-300 Configuration Manual page 27

Interface in the user program of the S7 station
You use the following program blocks in the user program:
Block type / instruction
SFB / FB12
SFB / FB13
SFB / FB15
SFB / FB14
SFB / FB8
SFB / FB9
SFC / FC62
1)
2)
Note
Remember word boundaries
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 doubleword format is located across such boundaries, data
inconsistency may arise during transfer using S7 communication!
Notes on S7 communication between PC/PG station and S7 station
Applications in a PC/PG station communicate with the S7 station via an OPC interface or
SAPIS7 interface for operator intervention, monitoring and control.
The S7 stations use the integrated program blocks (client and server functionality at both
ends).
The following general requirements must be met by a PC/PG station for S7 communication:
● The following are installed in the PC/PG:
● The CPs in the S7 stations are supplied with a MAC/IP address (use the default MAC
To be able to use S7 communication with the SIMATIC S7 PLC from the PC, address the
CPU module as the target in the SIMATIC S7 station in your PC application.
Configuring and commissioning S7 CPs for Industrial Ethernet
Configuration Manual, 09/2013, C79000-G8976-C182-13
BSEND
BRCV
PUT
GET
USEND
URCV
CONTROL (S7-400) /
C_CNTRL (S7-300)
you do not need to configure a connection on the server
for S7300
– an Ethernet CP;
– an interface for S7 communication: SOFTNET S7 for Industrial Ethernet or software
from the SIMATIC NET CD.
address or set an IP address).
Communication via Ethernet CPs in S7 stations
1.5 S7 communication via Industrial Ethernet
Client Server
x -
- x
x -
1)
x -
1)
x -
- x
x x
2)
Described in
Online help in STEP 7
27