Siemens S7-1200 System Manual page 515

The following example shows the communication between two CPUs that utilize 2 separate
connections for sending and receiving the data.
● The TSEND_C instruction in CPU_1 links to the TRCV_C in CPU_2 over the first
● The TRCV_C instruction in CPU_1 links to the TSEND_C in CPU_2 over the second
S7-1200 Programmable controller
System Manual, 03/2014, A5E02486680-AG
connection ("connection ID 1" on both CPU_1 and CPU_2).
connection ("connection ID 2" on both CPU_1 and CPU_2).
① TSEND_C on CPU_1 creates a
connection and assigns a connection
ID to that connection (connection ID 1
for CPU_1).
② TRCV_C on CPU_2 creates the
connection for CPU_2 and assigns the
connection ID (connection ID 1 for
CPU_2).
③
TRCV_C on CPU_1 creates a second
connection for CPU_1 and assigns a
different connection ID for that
connection (connection ID 2 for
CPU_1).
④
TSEND_C on CPU_2 creates a
second connection and assigns a
different connection ID for that
connection (connection ID 2 for
CPU_2).
Communication
10.2 PROFINET
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