There are two ways you can log data using CDU:
1) Using the Logging Control Window under Tools.
2) Using the Save Data& feature under tools as well. Using the logging control window allows you to view the graphical windows while monitoring the the data being saved. The other way is to capture any data that is seen on the com port. Here is how to do it.:
1) Save all the log commands into a text file. Ensure that the carriage return is at the end of each command.
2) Establish communications with the receiver using CDU
3) Make sure the receiver is running and tracking satellites
4) Close all the display windows on CDU leaving only the Console Window open
5) Click on Tools, then Save Data. You will be asked to specify the file and directory where the data will be captured to.
6) Click on Tools, then Run Batch to specify the text file containging all of your log commands.
7) Leave the CDU running until the data collection is complete.
8) Deselect Save Data& to close the logging file.
9) Exit CDU.