Ethernet Units Operation Manual

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Overview of FINS Communications Section 5-1
• Writing data, changing modes, reading detailed information about Units,
and so on, can be executed without any particular knowledge of commu-
nications procedures or network classification.
• Units and Boards that support FINS commands return responses auto-
matically, so there is no need for a program at the receiving end.
• The FINS communications service is mainly used between OMRON CPU
Bus Units, CPU Units, and Support Boards for FA Computers. By cor-
rectly setting information such as headers, however, it can also be used
from ordinary Ethernet communications devices.
The FINS communications service can be used from a PC with either of the
following three instructions:
• SEND(090)/RECV(098)
SEND(090) and RECV(098) are used to send and receive data (area read-
ing and writing).
• CMND(490)
CMND(490) is used to send FINS commands. The particular FINS com-
mands that are supported vary depending of the type of Unit or Board. For
details on FINS commands addressed to Ethernet Units, refer to Section
11 FINS Commands Addressed to Ethernet Units. For details regarding
FINS commands addressed to CS/CJ-series CPU Units, refer to the CS/
CJ-series Programmable Controllers Communications Commands Refer-
ence Manual (W342).
The following table shows how the FINS communications service is used by
the communications source and destination, for PC to PC and host computer
to PC.
Local node to remote node SEND(090)/RECV(098) CMND(490) (FINS commands)
PC to PC
Host computer to PC
• When the PC executes SEND(090) or
RECV(098), a program is not required for
receiving a response.
• When the PC receives a SEND(090) or
RECV(098) instruction, a program is not
required for processing the instruction.
CPU Unit CPU Unit
User program
PC PC
• When the PC executes CMND(490), a
program is not required for receiving a re-
sponse.
• When the PC receives a CMND(490) in-
struction, a program is not required for
processing the instruction.
Ethernet Unit
CPU Unit
CPU Unit
When addressed to
CPU Unit
User program
PC PC
• The host computer issues the data for the SEND(090)/RECV(098) or CMND(490) in-
struction as a UDP datagram. Programs are required for sending data and for receiving
and processing responses.
• If the PC receives a SEND(090) or RECV(098) instruction, a program is not required for
processing the instruction.
Ethernet Unit
CPU Unit
When addressed to CPU Unit
Host computer
UDP packet issued by user program
Data