Two Counter Measurement Method
For period and frequency measurements, you also can use a second counter. For most applications, the low frequency with one counter method is sufficient and desirable because it uses fewer resources. However, if you have a high-frequency or widely varying signal, you can use one of the two counter measurement methods—the high-frequency measurement method or the large-range measurement method. Depending on the rate of your input signal and measurement method used, your measurement is subject to different amounts of quantization error. In two counter applications, you only need to call the Create Channel function/VI once, specifying only the counter channel to which you want to connect your input signal. NI-DAQmx automatically takes care of making the internal routes necessary to perform the measurement across paired counters.