Supplementary information   
16.6 Communication services 
  CPU 410-5H Process Automation/CPU 410 SMART 
234  System Manual, 10/2013, A5E32631667-AA 
Job lengths and parameters for the different types of connection 
Table 16- 7  Job lengths and "local_device_id" parameter 
"local_device_id" parameter for the connection description 
Dev. ID  16#5 for CPU 0 
16#0 for CPU 0 
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. 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. 
Terminating a communication connection  
●  Use with TCP and ISO on TCP 
FB 66 "TDISCON" disconnects the communication connection between the CPU and a 
communication partner.  
●  Use with UDP 
FB 66 "TDISCON" disconnects the local communication access point. This means that 
the connection between the user program and communication layer of the operating 
system is terminated.