Siemens Simantic Net NCM for Industrial Ethernet S7 - Manual (Page 87)

Configuring Communication Connections
87
SIMATIC NET NCM S7 for Industrial Ethernet
C79000-G8976-C129–06
4.3 Connections
Characteristics of a Connection
A communication connection allows program-controlled communication between
two nodes on Industrial Ethernet with the following characteristics:
S
The data transfer is bi-directional, in other words, it is possible to transmit and
receive on the connection simultaneously.
S Both stations have the same rights, in other words, each station can trigger the
send and receive procedures in response to events.
S
The address of the communication partner is specified in the configuration.
The free UDP connection is the exception to this. Here, the address is specified
at the FC interface in the user program.
Communication
connection
Ethernet CP
Ethernet
node SIMATIC S7 station
with Ethernet CP
receive
send receive
send
Ethernet
node
receive
send receive
send
Communication
connection
Figure 4-3 Sending and Receiving via one Communication Connection
Note
The term “connection” is also used here for UDP. Reason: during configuration
(just as in TCP) the communication partners are assigned to each other and
therefore logically “connected”. In actual fact, with UDP there is no explicit
connection establishment between communication partners.