Download JW-51CM User`s Manual Version 1.0

Chapter 6: Outline of Function
6-3 Network parameter settings
The following items are set for use as network parameters in the EEPROM.
These parameters are read when the JW-51CM starts up, and they control the details of each operation.
1 IP address, subnet mask
2 Method for opening each type of connection (TCP_Passive/TCP_Active/UDP) and port No. to
use.
3 Address settings for the send/receive functions
4 Settings related to the specified buffer command
5 Settings related to the ring buffer command
6 Settings for routing
7 Settings related to the connection status flag
8 Settings related to the completion information of the computer link command
After the power is turned ON, the JW-51CM will open each channel according to the details stored in the
EEPROM. The method for opening a channel varies with the parameter settings, as shown below.
(1) TCP_Passive
The port which is opened after selecting the TCP_Passive mode waits for a connection from the other
station.
This mode can be used in communication target stations with a computer link function or when the
send/receive function is selected.
Connections opened in the TCP_Passive mode cannot be disconnected by the module using that
mode. The station opened in the TCP_Passive cannot open or disconnect any connection. However,
it can start instructions of the send/receive function. The port which is under opening the connection
cannot communicate with other stations.
(2) TCP_Active
The TCP_Active mode is used to open connections to other stations. This mode can be used with a
command triggering station using the send/receive functions. By using this method, the connection to
another station can also be broken. While a connection is open, the port cannot communicate with
other stations.
(3) UDP
The UDP mode is a mode not to open any connection. It can be selected by the computer link or with
send/receive functions. The UDP is less reliable than TCP, since it does not allow confirmation of the
data receipt (checking to see the data was received by the target station) at the data transmission
protocol stage.
[Example]
Set the open method used for the communication between PC1, PC2, and the host device A.
1 Host device A communicates with PC1 using the TCP over the computer link.
2 PC1 communicates with PC2 using the send command (TCP_Passive).
Host
device
A
1
PC1
PC2
2
TCP_Passive
TCP_Active
6·3
TCP_Passive
6