7.2.1 Open Connection - Hitachi EH-150 Applications Manual

7.2.1 Open connection

The procedure for opening connection is shown as Figure 7.7.
Host PC
(A-2)
(A) In case of active open setting
EH-ETH2 requests active open against host PC of passive
(A-1)
open status.
Host PC receives the request to connect from EH-ETH2,
(A-2) sends a reply of ready to open connection to EH-ETH2, and
waits ACK from EH-ETH2.
EH-ETH2 receives the reply from the host PC, and sends
(A-3)
back ACK.
Host PC requests active open against EH-ETH2 of passive
(B-1)
open status.
EH-ETH2 receives the request to connect from Host PC,
(B-2) sends a reply of ready to open connection to Host PC, and
waits ACK from Host PC.
Host PC receives the reply from the EH-ETH2, and sends
(B-3)
back ACK.
Figure 7.7
Caution
- In case of the task code communication, the way to open is fixed as passive open.
- In case of ASR connection, the way to open is selected as active or passive, which can configured in EH-ETH2
Configurator only.
The each ASR parameters are set properly and EH-ETH2 is in active mode to open ASR connection.
In this explanation, EH-ETH2 is own station and the other equipment is other station.
The following items are "ASR information".
(1) Select communication protocol
(2) Select active open or passive open
(3) Configure own logical port number
(4) Select specified or optional other station.
(5) Configure IP address of the other station (Only in case the other station is "specified".)
(6) Configure Logical port number of the other station. (Only in case the other station is "specified".)
ASR parameters are set in EH-ETH2 Configurator. Please refer to "Section 5.4" in details.
Chapter 7 Automatic Sending/Receiving function (ASR)
EH-ETH2
(A-1)
(A-3)
(A) In case EH-ETH2 is in active open
Description
(B) In case EH-ETH2 is in passive open
Description
Basic procedure to open connection
7-5
Host PC
(B-1)
(B-3)
(B) In case of passive open setting
Segment
Sending SYN flag
Sending SYN ACK
flag
Sending ACK flag
Segment
Sending SYN flag
Sending SYN ACK
flag
Sending ACK flag
EH-ETH2
(B-2)
EH-ETH2
internal status
Sending request to
connect
(SYN-SENT )
-
Connection opened
(ESTABLISHED )
EH-ETH2
internal status
Sending request to
connect
(SYN-RCVD)
Connection opened
(ESTABLISHED )