Execution of a TCP Open EF
TCP Open EFs are executed asynchronously with the PLC cycle. Each EF call triggers a transaction with the Ethernet module concerned (TSX ETY 5103 or TSX ETY 110WS).
The transaction starts at the end of the PLC cycle and may take several cycles to complete. It is therefore necessary to manage the sequencing of calls so as not to saturate the module or request an action before the previous one is complete.
It is possible to call several TCP/IP services in the same PLC cycle. However, it is not certain that they will be processed in the chronological order in which they were called.
NOTE: We advise you to wait until the execution of one function is complete before requesting a new service on the same socket.
For example, wait for the FCT_SOCKET EF to be returned before calling the FCT_BIND EF, and wait for the FCT_BIND EF to be returned before calling the FCT_LISTEN EF.
The number of TCP Open functions supplied, as well as the manner in which they are used have been deliberately reduced in order to simplify the implementation of these services.
In addition to this, certain parameters are a requirement of the TSX ETY 5103 module. These limitations are detailed as part of the description of the
FCT_SOCKET function.
