Precautions for TCP/IP communications
■Conditions for closing
In addition to when close is requested from the external device, the TCP/IP communications processing will be closed in the
following cases if 'Open completion signal' (Un\G1900000 to Un\G1900007) turns off.
• When alive check function times out
• When forced close is received from external device
■TCP/IP connection elements
The TCP/IP connection is managed with the following four elements. Only one connection containing the same four elements
can be created at one time. To use multiple TCP/IP connections simultaneously, ensure that one of the four elements is
different.
• IP address of the Ethernet-equipped module side
• Port number of the Ethernet-equipped module side
• IP address of the external device side
• Port number of the external device side
■Reconnecting with same connection
After closing the connection during TCP/IP communications, wait at least 500ms before reconnecting to a connection with the
same external device (IP address), own station port number, and external device port number.
If a wait interval cannot be provided before reconnecting, changing the own station port number on the Active open side and
connecting is recommended.
1 FUNCTIONS
1.4 Socket Communications
1
63