Specifications

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*1 For the open and close processing on the Ethernet module side shown
below, there are two methods:performing from the PLC CPU and by the
Ethernet module system. The method is determined by the following
parameter setting value for the Ethernet module on the GX Developer.
• The open and close processing by Passive open in the TCP/IP
communication
• The open and close processing in the UDP/IP communication
(1) If the following 1) and 2) are satisfied in the parameter settings for the
Ethernet module on GX Developer, the Ethernet module system
performs the open and close processings of the corresponding
connection.
No open and close processing from sequence programs is required.
(Refer to the next page for the setting screen.)
1) "Always wait for OPEN" is set for "Initial timing" of the operational
settings. (Common setting to all connections for users)
2) For the connection for users, the following are set for "Protocol"
and "Open system" of the open setting.
• "Protocol" = TCP, "Open system" = Unpassive
• "Protocol" = TCP, "Open system" = Fullpassive
• "Protocol" = UDP, "Open system" = (No setting is required)
REMARK
When the Ethernet module was started in the setting described above
(Connection set as "Protocol" = TCP)
• The open processing (Active open) from an external device makes
the connection open and enables data communication.
• For finishing the data communication, the close processing from the
external device disconnects the connection.
• If necessary, perform the open and close processing from external
devices, and executes data communication at any time.
However, when closing a connection from the PLC CPU side due to
a communication error while the connection is open, use the
CLOSE instruction in the sequence program.
In this case, as the wait for OPEN processing of the corresponding
connection will not be performed by the Ethernet module system, all
the subsequent open processing (using the OPEN instruction) and
close processing on the Ethernet module side must be performed
using the sequence program .
("Protocol" = UDP)
Starting the Ethernet module enables the data communication with
external devices.