National Instruments DAQ X Series User Manual

Contents
X Series User Manual xii ni.com
Chapter 7
Counters
Counter Timing Engine ................................................................................................. 7-2
Counter Input Applications ........................................................................................... 7-3
Counting Edges ............................................................................................... 7-3
Single Point (On-Demand) Edge Counting ...................................... 7-4
Buffered (Sample Clock) Edge Counting......................................... 7-5
Controlling the Direction of Counting.............................................. 7-5
Pulse-Width Measurement.............................................................................. 7-6
Single Pulse-Width Measurement .................................................... 7-6
Implicit Buffered Pulse-Width Measurement................................... 7-7
Sample Clocked Buffered Pulse-Width Measurement ..................... 7-8
Hardware-Timed Single Point Pulse-Width Measurement .............. 7-8
Pulse Measu rement ......................................................................................... 7-9
Single Pulse Measurement................................................................ 7-9
Implicit Buffered Pulse Measurement .............................................. 7-10
Sample Clocked Buffered Pulse Measurement ................................ 7-10
Hardware-Timed Single Point Pulse Measurement.......................... 7-11
Pulse versus Semi-Period Measurements ......................................... 7-11
Semi-Period Measurement.............................................................................. 7-12
Single Semi-Period Measurement .................................................... 7-12
Implicit Buffered Semi-Period Measurement................................... 7-12
Frequency Measurement
................................................................................. 7-13
Low Frequ
ency with One Counter ................................................... 7-13
High Frequency with Two Counters ................................................ 7-14
Large Range of Frequencies with Two Counters ............................. 7-15
Sample Clocked Buffered Frequency Measurement ........................ 7-16
Hardware-Timed Single Point Frequency Measurement ................. 7-18
Choosing a Method for Measuring Frequency ................................. 7-18
Period Measurement ....................................................................................... 7-22
Position Measurement..................................................................................... 7-23
Measurements Using Quadrature Encoders...................................... 7-23
Measurements Using Two Pulse Encoders ...................................... 7-25
Buffered (Sample Clock) Position Measurement ............................. 7-25
Hardware-Timed Single Point Position Measurement ..................... 7-26
Two-Signal Edge-Separation Measurement ................................................... 7-26
Single Two-Signal Edge-Separation Measurement.......................... 7-27
Implicit Buffered Two-Signal Edge-Separation Measurement ........ 7-28
Sample Clocked Buffered Two-Signal Separation Measurement.... 7-28
Hardware-Timed Single Point Two-Signal Separation
Measurement.................................................................................. 7-29
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National Instruments DAQ X Series Specifications

General

Brand	National Instruments
Model	DAQ X Series
Category	I/O Systems
Language	English