Supplementary information   
18.7 Communication services 
  CPU 410 Process Automation/CPU 410 SMART 
320  System Manual, 05/2017, A5E31622160-AC 
Job lengths and parameters for the different types of connection 
Table 18- 7  Job lengths and "local_device_id" parameter 
ISO on TCP  32 KB  1452 bytes 
"local_device_id" parameter for the connection description 
Dev. ID  16#5 for CPU 0, interface x5 
16#15 for CPU1, interface x5 
16#8 for CPU 0, interface x8 
16#18 for CPU1, interface x8 
16#0 for CPU 0 
16#10 for CPU1 
Establishing a communication connection 
●  Use with TCP and ISO on TCP 
Both communication partners call FB 65 "TCON" to establish the connection. In the 
configuration, you specify which communication partner activates the connection, and 
which one responds to the request with a passive connection. To determine the number 
of possible connections, refer to your CPU's technical specifications. 
The CPU automatically monitors and holds the active connection. 
If the connection is broken, for example by line interruption or by the remote 
communication partner, the active partner tries to reestablish the connection.  
If a subsystem of a fault-tolerance system is switched to STOP, the system retains the 
connections through the CPU switched to STOP and establishes them again after link-up.  
You do not have to call FB 65 "TCON" again. 
When FB 66 "TDISCON" is called or the CPU is in STOP operating state, an existing 
connection will be terminated. To reestablish the connection you must call FB65 "TCON" 
again. 
●  Use with UDP 
Both communication partners call FB 65 "TCON" to set up their local communication 
access point. This establishes a connection between the user program and operating 
system's communication layer. No connection is established to the remote partner. 
The local access point is used to send and receive UDP message frames.