Siemens SIMATIC ET 200AL, System Manual

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Communications services
3.4 Setting up a connection
Communication
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Function Manual, 05/2021, A5E03735815-AJ
Effects on the connection resources of the CPU
You can often choose between a configured or a programmed connection. Programmed
connection setup allows connection resources to be released following data transfer. Like
routed connections, programmed connections are not guaranteed, meaning that they are
only established when resources are available. With configured connection setup, the
resource is available after download of the configuration until the configuration changes
again. Corresponding resources are therefore reserved for connection establishment via
configured connections. The "Connection resources" table in the Inspector window of the CPU
displays an overview of connection resources already used and those still available.
How do I set up a connection?
Table 3- 5 Setting up the connection
Connection Automatically Programmed setup Configured setup
Programming device connection X - -
HMI connection X - X
Web communication X - -
OPC UA server communication X - -
OPC UA client communication - X -
Open communication via TCP/IP
connection
- X X
Open communication via ISO-on-
TCP connection
- X X
Open communication via UDP con-
nection
- X X
Open communication via ISO con-
nection
- X X
Open communication via FDL con-
nection
- X X
Communication via Modbus TCP
connection
- X -
E-mail connection - X -
FTP connection - X -
S7 connection* - - X
* Note that for an S7-1500 CPU you must enable the use of PUT/GET communication in the properties
of the CPU. You can find more information on this topic in the STEP 7 online help.
Additional information
You will find further information on the allocation of connection resources and the display of
connection resources in STEP 7 in the section Connection resources (Page 391).