Wow -- I hadn't really looked at these "simple" examples (not so simple!). However, it should be fairly easy to do what you want. Notice that the VI "Log Data" (in the Logging library) has the responsibility of dequeuing samples from the Data Queue and writing them to the TDMS file. What you really want to do is to write every "n-th" point (it's equivalent to "save a point every M minutes", but a little easier to program). Say your sampling rate is 100 Hz, and you want to save a sample every 2 minutes. That's 1 sample every 100*60*2 = 12000 samples. You could wrap a While loop around the Log Data code, wire True to the Stop terminal (this makes it a "Do Once" loop), run a Shift Register through the loop that increments a U32 counter (and thus becomes a "sample counter", and only pass the data to the TDMS file when the count is a multiple of 12000 (I presume you know how to do this -- one way is to write the sample counter to the top input of the Quotient and Remainder function, 12000 to the bottom input, then test if the remainder = 0).
If you want to change the frequency of logging, simply recompute the number of samples per logged sample, as described above.
