Specifications

2 - 11
2.3 Open/Close Processing
For data communication with external devices using the Ethernet module, a connection
must be established (connection of logic circuit) after completion of the initial
processing automatically carried out at module start up.
For the Ethernet modules, there are two connection types: one for the system and the
other for the user. Completing all of the open processing makes data communication
with external devices executable.
When the communication is completed, the close processing is performed for the
established connection.
The following describes the Ethernet module connection, and its open and close
processing.
(Diagram of data communication procedures)
Automatically started
Set parameters for the
Ethernet module through
GX Developer
Refer to "4.3 Settings and Procedures Prior to Starting the Operation"
Start up the PLC CPU
Initial processing
Open processing
Refer to (2)
(Connection for
user No.1 to 16)
Communication
using the MC
protocol
Communication
using fixed
buffer
Communication
using random
access buffer
Close processing
Refer to (3)
(Connection for system)
E-mail
sending/
receiving
MELSECNET/H,
MELSECNET/10
relay communi-
cation
Communication
using data link
instructions
File transfer
(FTP)
Communication
using Web
function
Communication
using GX
Developer
Communication
using the MC
protocol
(1) Connection of the Ethernet module
(a) Connection for system
1) This is a connection for users to perform data communication using the
special functions of the Ethernet module, as shown on the right side of the
above diagram.
2) The open processing is automatically performed at start of the Ethernet
module.
Users need not to open and close the connection.
(b) Connection for user
1) This is a connection for users to perform data connection using the basic
functions of the Ethernet module, as shown on the left side of the above
diagram.
2) User performs the open processing when starting data communication
with external devices and the close processing when finishing the data
communication.
3) According to the communication method set up for the data
communication with external devices, the connection is established.