Our initial goal was the acquisition of Load Cell Data (cable strength) for dredging, coring and sampling purposes, positioning, accurate timestamping of events and other geophyisical data on an oceanographic ship.
The positioning data were supposed to be provided through a standard
NMEA GPS interface, in particular the well known GGA, GLL
and ZDA sentences, or a combination of them, or, at least, the GGA.
With a minimum overhead, the ZDA sentence can be used to
synchronize the computer clock to the UTC time of the GPS clock. This can be
useful when no NTP servers are available on the network.
A Trimble TSIP interface was also made available, particularly for the
AcutimeTMreceiver.
Amongst many others instrumental interfaces we may cite for example magnetometers, gravity meters,
cable layouts, and so on.
The GUI interface was designed to be flexible enough to accommodate all the necessary
parameters for each single instrument. Once the server application is launched on a
particular TCP/IP port, one client or many CLIENTS are allowed to connect and visualize and store the
ongoing data.
The software can have both the server (option -server) and the client
(option -client) active, however, the server instance
should be used only by trained personnel, since it is the core of system and it can be
prone to errors or problems if not properly programmed. The client side is
much less prone to errors and can be freely distributed to clients.
A more powerful, fully featured software instance, allows the
concurrent presence on the same GUI of the server and client runs.
The acquired data are available in a user selected directory as set during the initialization phase. They can be copied on the net using the standard Unix tools. The data arriving from each sensor are recorded 'as-is' on disk. The (sort) merge of the data in individual files is relatively easy since each record have the timestamp. The unix time field can be appropiately used to achieve this. See Appendices C containing data and some pieces of code for reading it.