National Instruments NI 660 Series User Manual

Chapter 2 Device Overview
© National Instruments Corporation 2-5 NI 660x User Manual
Example Application That Works Correctly (No Duplicate Counting)
Figure 2-4 shows an external buffered signal as the period measurement
Source.
Figure 2-4. Example Application That Works Correctly
On the first rising edge of the Gate, the current count of 7 is stored. On the
next rising edge of the Gate, the counter stores a 2 because two Source
pulses occurred after the previous rising edge of Gate.
The counter synchronizes or samples the Gate signal with the Source
signal. So the counter does not detect a rising edge in the Gate until the next
Source pulse. In this example, the counter stores the values in the buffer on
the first rising Source edge after the rising edge of Gate.
Gate
Source
Counter Value
Buffer
2
7
7
67 12 1
Rising Edge
of Gate
Counter detects rising edge
of Gate on the next rising
edge of Source.

National Instruments NI 660 Series Specifications

General

Brand	National Instruments
Model	NI 660 Series
Category	PCI Card
Language	English