The Sea-Bird CTD configuration file (XMLCON), and other file types.

The instrument configuration file

Instrument configuration files are files located on your computer and determine how the CTD signal should be interpreted. The configuration file (xmlcon) enables the PC to correctly interpret the data file/stream. These files can be edited using a SeaSoft program (image 1) either by double clicking it on the windows explorer or by pressing "configure inputs" in SeaSave and some other SeaSoft programs.

Image 1: instrument configuration file interface on SeaSoft.

1. In the top section of the configuration editor, the general setup of the device is determined. It is crucial to ensure that the sampling mode (Profile or Moored), the number of "External voltage channels", and the "Serial RS232C" settings match the instrument setup. Mismatches will results in a "Sacn length error".
2. In the middle section of the configuration editor, the file specifies additional data that is added to the sampling file/stream. Things like GPS data (in NMEA format).
3. In the bottom part of the file, the number of sensors that are mounted on the CTD, Their type and position is determined. This section of the configuration is the most important because it determines the calibration coefficients and therefore the accuracy of the sampling. By double clicking a sensor in the list you can open a specific sensor calibration file (image 2) where you can change an instrument calibration.

Image 2: Calibration window for specific instrument.

The .xmlcon should be changed whenever you change instrument configuration on your device or whenever you calibrate a sensor. Changing Simple calibration can be performed by double clicking an instrument, Then you can change the calibration coefficients either manually or by by importing an instrument calibration file (it's a specific XML file). Changing the order, number or type of mounted sensors (white lines in image 1) can be performed by right clicking a line and then "select new voltage sensor".

When sampling with a CTD using SeaSave, Some of the configuration file is added to the instrument output (.hex file) as a header. you can review this section by opening a hex file using a text editor.

The .psa file

.psa file (short for program setup files) are file that configure a singe seabird program. each of the seabird software suite programs (SeaSoft) has its own .psa file. The functioning of the software is defined using the .psa file. For instance, in the image and screencast below you can see the serial port communication definitions in SeaSave, things like number of serial ports used by SeaSave, their port numbers and baud rates. all of those definitions are save in the .psa file.

Image 1: Some of the content defined using the SeaSave .psa file

When exiting one of the SeaSoft programs and if you made any change to the setup file you are asked whether to save the changes. For instance:

1. When sampling using SeaSave you change the output data file name every time and therefore either you save the setup file or no it doesn't matter because you will have to change it again 
2. You used your friends CTD once and changed the baud rate, its advised not to save the .psa after sampling. 

When asked to save the .psa file. think before you push "YES" (or "NO")

 The dsa file

The dsa (device setup file) is a file that defines the configuration of items within the SEaSave data window. Which sensors to display in a window, which variables etcetera. the SEaSave .psa file is linked with each windows .dsa file.