Typically, NI-DAQmx uses one of the internal counter timebases when performing counter measurements. Use this property to specify an external timebase and produce custom measurement ranges that are not possible with the internal timebases.

You also can use this property to chain counters together. By using the output of a counter as the timebase of another counter, you can effectively widen a counter. For example, you can chain two 24 bit counters together to produce one 48 bit counter.