If we use the total station for acquiring position data, does Hydromagic register the sytem time of the total station when it saves a position value or does it use the system time oft he pc, where Hydromagic is installed?

When recording incoming data to the internal raw data format, data is most of the times time tagged with the PC time.

If the plugin you are using has an option to use the time of the device you are connecting, then the time of the device will be used if this option is checked.

We recommend to use this option when depth and position data are always time tagged by a single device (for instance an echo sounder which has a GNSS receiver connected and uses the GNSS timestamps to synchronize the time, like the CEESCOPE).

example of a Hydromagic raw data file opened in Notepad.