Specifications

2 - 7
As shown in the diagram below, set IP addresses and usage conditions (e.g.
sending/receiving, with/without procedures) of external devices to respective fixed
buffer areas(No.1 to 16) when opening a connection (logic circuit) of the Ethernet
module to fix each external device to each buffer. (*1)
*1 The connection No. (1 to 16) used for data communication are the same as
those for the fixed buffer.
For receiving from external device 8
Fixed buffer No.2
Fixed buffer No.3
Fixed buffer No.16
For sending to external device 1
For sending to external device 28
External device 1
External device 28
Fixed buffer No.1
For receiving from external device 1
External device 8
(2) Differences between with and without procedures
The following shows the differences between the fixed buffer communication
(Procedure exist) and the fixed buffer communication (No procedure).
Procedure exist No procedure
Communication method
The application programs of the local
station’s PLC CPU and an external device
communicate through handshaking.
The application programs of the local
station’s PLC CPU and an external device
communicate without handshaking (Data
reception of data at external devices cannot
be confirmed for data transmission.)
Applications for
connection opened
Communications using fixed buffer, random
access buffer, and MC protocol are available.
Only fixed buffer communication is available.
Message format of
application data unit
Message format determined by the Ethernet
module
No restrictions on the message format
(Communication is available in the message
format of the external device.)
Communication data
code
ASCII code or Binary code Binary code
Unit of data length for
dedicated instructions
Word Byte
(3) External devices capable of exchanging data
The communication using the fixed buffer can be performed with the following
external devices.
1) External devices that are connected to the same Ethernet as the Ethernet
module
2) External devices that are connected to other Ethernet networks via routers
Router
Personal computer
PLC CPU
(Access station)
Personal computer
Ethernet-2
Ethernet-1
2)
1)