FINS/TCP Method

Section 7-4

FINS/TCP Connection Status (Word n+23)

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 an error in communications with a remote node or a FINS command (i.e., FINS/TCP CONNECTION REMOTE NODE CHANGE REQUEST).

15 14 13 12 11 10 09 08 07 06 05 04 03 02 01 00

n+23

*: Bit 15 corresponds to connection No. 16, bit 00 to connection No. 1, etc.

FINS/TCP

With FINS/TCP, FINS node addresses are exchanged immediately after a

Communications

connection is established. This makes it possible to determine the FINS node

Procedure

addresses to which the 16 connection numbers are connected, and to man-

 

age them in an internal table.

Personal computer

(Client)

Example:

IP address C

FINS node address A

Active open

Ethernet Unit

(Server)

Example:

IP address S

FINS node address B

Passive open

Connection request (CS)

Connection established

Connection established

Local node address sent

FINS node address A sent

Connection established

Remote node address received

Remote node address received

FINS frame sent

FINS node address B sent

Local node address sent

FINS frame sent

Full duplex communications

FINS node addresses exchanged

Normal data 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: command code 27 30 hexa- decimal) is sent by the client.

When there is no response from the client when the keep-alive function is in effect.

If a command other than FINS FRAME SEND is received from the client, the connection will close after the FINS FRAME SEND ERROR NOTIFI- CATION command is sent.

After a connection has been established as a FINS/TCP client, it can be termi- nated in the following ways.

• If the connection is closed by the server.

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Omron CJ1W-ETN21 operation manual Communications, FINS/TCP Connection Status Word n+23, Age them in an internal table