National Instruments cDAQ-9185 - Page 9

Contents
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Using the Watchdog Timer............................................................................... 5-14
Getting Started with DO Applications in Software ..........................................5-14
Digital Input/Output Configuration for NI 9401 ......................................................5-14
PFI.....................................................................................................................................5-14
PFI Filters .................................................................................................................5-14
Chapter 6
Counters
Counter Timing Engine .................................................................................................... 6-2
Counter Triggering ........................................................................................................... 6-3
Counter Input Applications............................................................................................... 6-3
Counting Edges......................................................................................................... 6-4
Single Point (On-Demand) Edge Counting ...................................................... 6-4
Buffered (Sample Clock) Edge Counting.........................................................6-5
Controlling the Direction of Counting..............................................................6-5
Pulse-Width Measurement........................................................................................6-6
Single Pulse-Width Measurement .................................................................... 6-6
Implicit Buffered Pulse-Width Measurement................................................... 6-7
Sample Clocked Buffered Pulse-Width Measurement .....................................6-7
Pulse Measurement ................................................................................................... 6-8
Single Pulse Measurement................................................................................ 6-8
Implicit Buffered Pulse Measurement .............................................................. 6-8
Sample Clocked Buffered Pulse Measurement ................................................ 6-9
Semi-Period Measurement........................................................................................6-10
Single Semi-Period Measurement .................................................................... 6-10
Implicit Buffered Semi-Period Measurement................................................... 6-10
Pulse versus Semi-Period Measurements .........................................................6-11
Frequency Measurement...........................................................................................6-11
Low Frequency with One Counter....................................................................6-11
High Frequency with Two Counters................................................................. 6-12
Large Range of Frequencies with Two Counters ............................................. 6-13
Sample Clocked Buffered Frequency Measurement ........................................6-14
Choosing a Method for Measuring Frequency ................................................. 6-15
Which Method Is Best?..................................................................................... 6-17
Period Measurement ................................................................................................. 6-19
Position Measurement............................................................................................... 6-19
Measurements Using Quadrature Encoders...................................................... 6-20
Channel Z Behavior .................................................................................................. 6-20
Measurements Using Two Pulse Encoders.......................................................6-21
Buffered (Sample Clock) Position Measurement ............................................. 6-21
Two-Signal Edge-Separation Measurement ............................................................. 6-22
Single Two-Signal Edge-Separation Measurement .......................................... 6-23
Implicit Buffered Two-Signal Edge-Separation Measurement ........................ 6-23
Sample Clocked Buffered Two-Signal Separation Measurement ....................6-23
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