Siemens CM 1542-5 Operating Instructions Manual page 30

Configuration, programming
4.3 Program blocks for FDL
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 connection must also be terminated by calling TDISCON. Make sure that
you take this into account in your programming.
Configured and programmed FDL connections
The following types of FDL connections can be established:
● Configured FDL connections
These connection types are configured in the STEP 7 program editor, see below. TSEND
/ TRCV or TUSEND / TURCV are used as the blocks.
– Specified connection
– Unspecified connection
– Broadcast connection
– Multicast connection
● Programmed FDL connections
These connection types cannot be configured in the STEP 7 program editor. Instead for
these connection types either calling TCON along with TSEND/TRCV or
TUSEND/TURCV is required or TSEND_C / TRCV_C.
– Specified connection
– Unspecified connection
– Unspecified Layer 2 connection
– Broadcast connection
– Multicast connection
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Fully configured connection between two partners
Configured connection with an unspecified partner
Connection with all connected partners
Connection with several defined partners
Fully configured connection between two partners
Configured connection with an unspecified partner
Programmed FDL-Verbindung with an unspecified partner with free layer 2 access
Connection to all connected partners
Connection to several defined partners
Operating Instructions, 11/2018, C79000-G8976-C290-04
CM 1542-5