NI-DAQmx: Buffered Period Measurement with External Counter Source

This program demonstrates how to make a buffered edge count with reset using the buffered period measurement. The number of edges of a source signal will be counted and each time the gate signal has a rising edge the count will be stored in the buffer and reset.

This program demonstrates how to make a buffered edge count with reset using the buffered period measurement. The signal to be measured is connected to the source of the counter by selecting the corresponding PFI line on the front panel. The number of edges of the source signal is counted between the rising edges of the gate signal. Once a rising edge of the gate signal is observed, the count value is moved into the buffer and the count is reset. This functionality is shown in Figure 1.

The typical buffered period measurement will measure the gate signal using a known internal time base as a reference. Counting the number of edges of the known time base between rising edges of the gate signal allows for a calculation of the period of the gate signal. The output is in seconds by default and is based on the known rate and the number of edges counted. This example changes the units of the output to ticks, so scaling is not a factor. This example also changes the counter source from an internal time base to the selected channel.

*NOTE: The first result of the measurement is not an accurate representation because it is a measure of the number of edges of the source signal between the beginning of the measurement and the first rising edge of the gate.

 

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Figure 1: Example buffered edge count with reset measurement 

Requirements

Filename: buffered_edge_count_reset.vi

Software Requirements

Application Software: LabVIEW Base Development System 8.0

Hardware Requirements

Hardware Group: CompactDAQ, Multifunction DAQ (MIO), Counter/Timers (TIO)
Driver: NI-DAQmx 8.7.1

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