Omron CJ1W-EIP21 - 10-2010 Operation Manual page 232

FINS/TCP Method
Note
FINS/TCP
Communications
Procedure
Personal computer
(Client)
Example:
IP address C
FINS node number A
Active open
Connection established
Local node No. sent
Remote node No. received
FINS frame sent
204
FINS/TCP Connection Status (Word n+24)
While a connection with a remote node is established, the bit corresponding to
the FINS/TCP connection status turns ON in the section of the CPU Bus Unit
words allocated in the CIO Area. The bit turns OFF if the connection is termi-
nated by a communications error or a FINS command (i.e., FINS/TCP CON-
NECTION REMOTE NODE CHANGE REQUEST).
15 14 13 12 11 10 09
n+24
*: Bit 15 corresponds to connection No. 16, bit 00 to connection No. 1, etc.
The starting word of the FINS/TCP Connection Status Area is different in the
CS1W-ETN21 and CJ1W-ETN21 Ethernet Units; it is n+23 in the Ethernet
Units. If a ladder program using FINS/TCP communications was created for
Ethernet Units, and is being reused for EtherNet/IP Units and built-in Ether-
Net/IP ports, change the word starting word address for this area from n+23 to
n+24.
With FINS/TCP, FINS node addresses are exchanged immediately after a
connection is established. This makes it possible to determine the FINS node
addresses to which the 16 connection numbers, and to manage them in an
internal table.
Example:
IP address S
FINS node number B
Connection request (C→S)
FINS node number A sent
Remote node No. received
FINS node number B sent
Full duplex communications
After a connection has been established as a FINS/TCP server, it is termi-
nated in the following ways.
• When the connection is closed by the client.
• When a FINS command to close the connection (FINS/TCP CONNEC-
TION REMOTE NODE CHANGE REQUEST) is sent by the client.
• When there is no response from the client when the keep-alive function is
in effect.
08 07 06
Ethernet/IP Unit
(Server)
Passive open
Connection established
Connection established
FINS node numbers exchanged
Local node No. sent
FINS frame sent
Normal data communications
Section 8-3
05 04 03 02 01 00