Siemens SIMATIC NET ET 200SP - Page 97

Programming (OUC)
5.1 Program blocks for OUC
CP 1542SP-1, CP 1542SP-1 IRC, CP 1543SP-1
Operating Instructions, 01/2017, C79000-G8976-C426-03
97
SDT only for CP 1543SP-1
The CP 1543SP-1 can use the following SDT for data transfer with Security function:
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TCON_IP_V4_SEC
For the secure transfer of data via TCP
Connection establishment and termination
Connections are established using the program block TCON. Note that a separate program
block TCON must be called for each connection.
A separate connection must be established for each communications partner even if
identical blocks of data are being sent.
After a successful transfer of the data, a connection can be terminated. A connection is also
terminated by calling "TDISCON".
Note
Connection abort
If an existing connection is aborted by the communications partner or due to disturbances on
the network, the co
nnection must also be terminated by calling TDISCON. Make sure that
you take this into account in your programming.