6 Configure the Operation Modes
6.2.2.2.1 Driver Mode
Only very few parameters have a function in Driver Mode. NetCom
+
is operating as a Server in TCP mode, it accepts two connections per serial port. This mode is
required when the driver software for Virtual Com Ports shall be used.
Mode
Driver Mode
TCP Port(Control)
[2000 ]
TCP Port(Data)
[2001 ]
KeepAliveMode
On Connect
KeepAliveInterval
[0
]
Figure 76: Driver Mode parameters
The first connection is used to transmit the serial data, this is the
TCP Port(Data)
. And the other
is used to transmit control information,
TCP Port(Control)
. This control connection includes the
configuration of the serial port, as well as signals for changed Modem Status lines. This mode is
required when the serial port is operated via the Virtual Com Driver, it is the default.
In Driver Mode the NetCom
+
accepts only one client per serial port. An attempt to connect a
second client is actively refused. This is required to avoid confused configurations and data on the
serial port.
The NetCom
+
can monitor an open connection. This is controlled by the
KeepAliveMode
, which
has three settings:
Off
,
On Connect
and
Polling
.
•
Off
: never send KeepAlive packets.
•
On Connect
: when a client is trying to connect to the server and there was a connection
before, the server checks if the first connection still exists. If it does not exist anymore, the
server accepts the new connection.
This option is the default configuration.
•
Polling
: the server checks in
KeepAliveInterval
(seconds), if a connection still exists.
If the network connection between client and NetCom
+
seems to be unstable, the configuration of
Polling
may be desired. This way the NetCom
+
may detect when the connection got lost. When
the NetCom
+
detects a lost connection, this is discarded, so the NetCom
+
is available for other
clients. Disabling the check is not recommended.
September 2016
NetCom Plus User Manual
77
