Siemens S7-300 - Page 84

SEND/RECEIVE interface in the user program
4.1 How the SEND/RECEIVE interface works on the CPU
Configuring and commissioning S7 CPs for Industrial Ethernet
84 Configuration Manual, 09/2013, C79000-G8976-C182-13
The diagram below illustrates what happens: Using AG_SEND / AG_LSEND / AG_SSEND
and AG_RECV / AG_LRECV / AG_SRECV, the user program instructs the Ethernet CP to
send or receive data on the configured connection.
Amounts of data and configuration limits
The Ethernet CP can transfer (send or receive) the following amounts of data per job:
Program block
ISO-Transport
ISO-on-TCP
TCP
UDP
Send
AG_SEND *
)
AG_LSEND **
)
AG_SSEND ***
)
8192 bytes
8192 bytes
1452 bytes
8192 bytes
8192 bytes
1452 bytes
8192 bytes
8192 bytes
1452 bytes
2048 bytes
2048 bytes
1452 bytes
Received
AG_RECV *
)
AG_LRECV **
)
AG_SRECV ***
)
8192 bytes
8192 bytes
1452 bytes
8192 bytes
8192 bytes
1452 bytes
8192 bytes
8192 bytes
1452 bytes
2048 bytes
2048 bytes
1452 bytes
*)
- With older versions of AG_SEND / AG_RECV (up to V3.0), the data area is always restricted to a
maximum of 240 bytes.
-
With the S7-400, the data area of AG_SEND / AG_RECV is always restricted to a maximum of 240
bytes.
**) S7
-400 only
***) Only with the S7
-400 with CPUs as of version V5.1 and the following CPs:
- CP 443-1 (as of 6GK7 443-1EX20.../ EX30)
- CP 443-1 Advanced (as of 6GK7 443-1GX20.../ GX30)