TCP/IP Communication Profile
The following figure shows the composition of a typical stack as it relates to the :
The port reserved for the BMX NOE 01x0 or the Ethernet port on the BMX P34 20x0 is TCP . To access these modules’ server, do so through this port.
Timeout on TCP Connection
If a TCP connection cannot be established (when the destination is absent for example), a timeout error occurs after 80 seconds.
Confirm that each communication function timeout is set to a value higher than 80 seconds if the first exchange was not successfully completed.
NOTE:
If you are using a derived function block (DFB), you can add a timer to verify the completion of a function block:
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To verify that the function block was incomplete, write an On timer to start when the function is triggered. If the time goes beyond the preset, the variable associated with the pin is set.
Result: You receive a timeout error indicating the communication did not work.
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To verify that the function block was complete, watch the active, error, and complete outputs of the communication function block. (Depending on the blocks used, they may not be present.) Use the complete as an event. If the event completes within the time set, no alarm is recorded. (Essentially, it resets it self.)
The TCP layer sends a
"keep alive" frame almost every two hours so that breaks in connection can be detected (for example, cable disconnection, detection of power outage from the client by a server, etc.).
