Add a timer to your form, enable it, set its interval to what you want (maybe 1000 ms).
Set: BasicDataLogger21.EnableLogging = False
Double click the timer to enter its Tick event and add your code to check the current date/time, compare it to the date/time you want and then start the logging with:
BasicDataLogger21.EnableLogging = True
Then check the date/time again and stop the logging:
BasicDataLogger21.EnableLogging = False