Specifications

2 - 8
(4) Outline of data sending/receiving procedures
Data sending/receiving is performed as shown in the following figure.
(a) At TCP/IC communication
1) Fixed buffer communication (Procedure exist)
PLC CPU
Send
request
Completion
Receive
completion
Receive
completion
confirmation
Ethernet module
BUFSND
instruction
BUFRCV
instruction
Fixed buffer-n
Fixed buffer-m
Data sending
ACK receiving
Data receiving
ACK receiving
External device
Receive
processing
Send
processing
Response receiving
Response sending
ACK sending
ACK sending
2) Fixed buffer communication (No procedure)
PLC CPU
Send
request
Completion
Receive
completion
Receive
completion
confirmation
Ethernet module
Data sending
ACK receiving
Data receiving
ACK sending
External device
BUFSND
instruction
BUFRCV
instruction
Fixed buffer-n
Fixed buffer-m
Receive
processing
Send
processing
(b) At UDP/IP communication
1) Fixed buffer communication (Procedure exist)
PLC CPU
BUFSND
instruction
BUFRCV
instruction
Send
request
Completion
Receive
completion
Receive
completion
confirmation
Ethernet module
Fixed buffer-n
Fixed buffer-m
Data sending
Response receiving
Data receiving
Response sending
Receive
processing
Send
processing
External device
2) Fixed buffer communication (No procedure)
Data sending
Data receiving
PLC CPU
Sending
request
Completion
Receive
completion
confirmation
Ethernet module
BUFSND
instruction
BUFRCV
instruction
Fixed buffer-n
Fixed buffer-m
External device
Receive
processing
Send
processing
Receive
completion