Chapter 5
72
Gate Types
The edge or level of the Counter 0 Gate signal determines when a counter/timer operation is
enabled. Using software, you can specify one of the following gate types:
•
None
– A software command enables any counter/timer operation immediately after
execution.
•
Logic-high level external gate input
– Enables a counter/timer operation when Counter 0
Gate is high, and disables a counter/timer operation when Counter 0 Gate is low. Note
that this gate type is used for event counting and rate generation modes; refer to
for more information about these modes.
•
Falling-edge external gate input
– Enables a counter/timer operation when a high-to-low
transition is detected on the Counter 0 Gate signal. In software, this is called a low-edge
gate type. Note that this gate type is used for edge-to-edge measurement mode; refer to
for more information about these modes.
•
Rising-edge external gate input
– Enables a counter/timer operation when a low-to-high
transition is detected on the Counter 0 Gate signal. In software, this is called a high-edge
gate type. Note that this gate type is used for edge-to-edge measurement operations; refer
to
for more information about these modes.
Pulse Duty Cycles
Counter/timer output signals from the modules are high-to-low going signals.
The duty cycle (or pulse width) indicates the percentage of the total pulse output period that is
active. In rate generation mode, the duty cycle is fixed at 50% for the DT9812, DT9813, and
DT9814 Series modules.
illustrates a high-to-low going output pulse with a duty
cycle of 50%.
Figure 22: Example of a Pulse Output SIgnal with a 50% Duty Cycle (High-to-Low Going)
Total Pulse Period
Active Pulse Width
low pulse
high pulse
Содержание DT9812 Series
Страница 1: ...DT9812 UM 20769 R DT9813 and User s Manual DT9814 Series Title Page ...
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Страница 12: ...About this Manual 12 ...
Страница 13: ...13 1 Overview Key Hardware Features 14 Supported Software 15 Getting Started Procedure 16 ...
Страница 17: ...Part 1 Getting Started ...
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Страница 26: ...Chapter 2 26 ...
Страница 53: ...Part 2 Using Your Module ...
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Страница 76: ...Chapter 5 76 ...
Страница 88: ...Chapter 6 88 ...
Страница 89: ...89 7 Troubleshooting General Checklist 90 Technical Support 92 If Your Module Needs Factory Service 93 ...
Страница 94: ...Chapter 7 94 ...
Страница 113: ...113 B Screw Terminal and Connector Pin Assignments ...
Страница 124: ...Index 124 writing programs in C C 15 Visual Basic 15 Visual Basic NET 15 Visual C 15 Visual C 15 ...