The configuration file defines the instrument — auxiliary sensors integrated with the instrument, and channels, serial numbers, and calibration dates and coefficients for all the integrated sensors (conductivity, temperature, and pressure as well as auxiliary sensors). Sea-Bird’s real-time acquisition and data processing software uses the information in the configuration file to interpret and process the raw data (sensor frequencies and voltages). If the configuration file does not match the actual instrument configuration, the software will not be able to interpret and process the data correctly. When Sea-Bird ships a new instrument, we include a .con or .xmlcon file that reflects the current instrument configuration. The file is named with the instrument serial number, followed with the .con or .xmlcon extension. For example, for an instrument with serial number 2375, Sea-Bird names the .xmlcon file 2375.xmlcon. You may rename the configuration file if desired; this will not affect the results. (Click here to see an example of where to find the serial number on your instrument) Seasave V7 and SBE Data Processing version 7.20 (2009) introduced .xmlcon files (in XML format). Versions 7.20 and later allow you to open a .con or .xmlcon file, and to save it to a .con or .xmlcon file. To view or modify the configuration file, use the Configure Inputs menu in Seasave V7, or the Configure menu in SBE Data Processing. Notes: Seasave V7 and SBE Data Processing check that the serial number in the configuration file matches the instrument serial number in the .dat or .hex data file. If they are not the same, you will get an error message. The instrument serial number can be verified by sending the Status command (DS or #iiDS, as applicable) in the appropriate terminal program. SBE 16, 16plus, 16plus-IM, 16plus V2, 16plus-IM V2, 19, 19plus, 19plus V2, 21, and 49 — The instrument serial number is the same as the serial number of both the conductivity and temperature sensors. SBE 37 (older), 39, 39plus, and 48 — These instruments store calibration coefficients internally and do not accept auxiliary sensors, so they do not have configuration files. SBE 37 (newer) that is compatible with SeatermV2 terminal program — SeatermV2 creates a configuration file for these instruments when it uploads data. The configuration file can then be used for processing the data in SBE Data Processing. The calibration date in the configuration file is for information only. It does not affect the data processing. When Sea-Bird recalibrates an instrument, we ship the instrument with a Calibration Sheet showing the new calibration coefficients (1 calibration sheet per sensor on the instrument that was calibrated). Sea-Bird also supplies a .xml file with the calibration coefficients for each calibrated sensor. The .xml files can be imported into Seasave or SBE Data Processing, to update the calibration coefficients in the configuration file. — For CTDs: Sea-Bird also creates a new configuration file, which includes calibration coefficients for the CTD as well as any auxiliary sensors that were returned to Sea-Bird with the CTD. If you did not return the auxiliary sensors with the CTD, you need to update the configuration file to include information on the auxiliary sensors that you plan to deploy with your CTD.