Mitsubishi Electric FX5 User Manual page 80

■Precautions for Passive open communication
• Configure an interlock circuit using the Open completion signal (SD10680.n) and Open request signal (SD10681.n) in the
program. The following chart shows on/off timings of the Open completion signal and Open request signal.
Open completion signal (SD10680.n)
Open request signal (SD10681.n)
• When a device establishes a connection by Passive open, the IP address and port number of the connected device can be
acquired using the SP.SOCCINF instruction.
• On TCP, one connection is established with one target device. To communicate with multiple devices from one port number,
prepare the same number of connections as the number of target devices. A connection that exceeds the preset number of
connections will be disconnected immediately.
• Do not accept a connection from a device until the CPU module is placed in the wait-for-open state. If a TCP connection
request is received before entering the wait-for-open state after completion of CPU startup, the request will be recognized
as an error, and a forced close message for the connection will be returned to the interfacing device. In this case, wait until
the CPU state is changed to the wait-for-open state and then retry the connection from the device.
• Do not execute the SP.SOCCLOSE instruction in a program. Doing so will disable data transfer since the Open completion
signal and Open request signal of the corresponding connection turn off for close processing. To reopen the closed
connection, execute the SP.SOCOPEN instruction.
7 SOCKET COMMUNICATION FUNCTION
78
7.1 Communication Using TCP
ON
OFF
ON
OFF
TCP connection completed
by the communication target
TCP disconnection completed
by the communication target
This device is
always ON.