Campbell Scientific NL240 Wireless Network Link Interface - Manual (Page 59)

Appendix C. NL240 Settings
RS-232 Service Port Number
This setting is used when the RS-232 port is configured as a Serial Server or
MODBUS/TCP gateway. To communicate with a TCP/IP server, the client
application must open a socket to that server. The socket of a specific server is
uniquely identified by an IP address of the host where the server is running and
a port number associated with the server application on that host. This entry is
where the port number of the server is set. Ensure that the client application is
set to use the same port number as configured here. Most MODBUS/TCP
applications use port 502. (range 1..65535)
RS-232 Baud Rate
This setting specifies the baud rate of the RS-232 port. The connected device
must be set to communicate at the same baud rate.
RS-232 RTS
The NL240 asserts the RTS and DTR lines when doing RS-232 communications.
This setting allows the user to disable the RTS line if needed so that it will not be
asserted. Some hardware will not function if the RTS line is asserted, but
typically, it is not necessary to change this setting from its default (enabled).
RS-232 TCP Timeout
This setting will determine how fast the device will time out on the open TCP
connection. For Serial Server and MODBUS/gateway configurations, the
device will close the TCP connection if no activity is detected for the timeout
period. For the TCP Client configuration, the device will close the TCP client
connection if no activity is detected and then immediately open another
connection with the remote server. This behavior helps to ensure that the
connection is functional as the device does not know the frequency or nature of
the expected data. Set to 0 for no timeout (not recommended). (range 0..999)
(seconds)
RS-232 Always On
This setting controls whether the device is allowed to shut down the RS-232
port when it is not in use in order to conserve power. Typically it is not
necessary to change this setting from its default [Auto].
Auto
Based on the RS-232 port configuration, the device will decide which of
the following two modes is more likely to be desired and will operate in
the according manner.
Always On
The device will not power down the RS-232 port. The port will remain
active always. As a result the processor cannot enter its lowest power
state. Keeping the port always on may be necessary because when the
RS-232 port is powered down there is a wake-up latency and the first few
bytes that come in on the port will be missed. If this behavior is
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