Open User Communication Library - Siemens SIMATIC S7 System Manual

Libraries

9.4 Open user communication library

9.4 Open user communication library
The STEP 7-Micro/WIN SMART Open User Communication (OUC) library instructions
create the tables required by the OUC instructions (Page 217) (TCON, TSEND, TRECV, and
TDCON). The library instructions build the table as needed, call the OUC instruction, and
then present you the status values on the outputs of the library instruction. The CPU uses
library memory to create a table to pass to the OUC instructions. The Open User
Communication library requires 50 bytes of V memory.
The library instructions are as follows:
● TCP_CONNECT: Create a TCP connection.
● ISO_CONNECT: Create an ISO-on-TCP connection.
● UDP_CONNECT: Create a UDP connection.
● TCP_SEND: Send data instruction for TCP and ISO-on-TCP connections.
● TCP_RECV: Receive data instruction for TCP and ISO-on-TCP connections.
● UDP_SEND: Send data instruction for UDP connections.
● UDP_RECV: Receive data instruction for UDP connections.
● DISCONNECT: Terminate the connection for all protocols.
Note
The CPU models CPU CR20s, CPU CR30s, CPU CR40s, and CPU CR60s have no
Ethernet port and do not support any functions related to the use of Ethernet
communications.
Note
Only call the library functions from either the main program or from interrupt routines, but not
both.
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System Manual, V2.3, 07/2017, A5E03822230-AF
S7-200 SMART