
Principles of Operation
113
The conversion rate of each channel is determined by the frequency of the A/D sample clock;
refer to
for more information on the A/D sample clock. The conversion rate of each
scan is determined by the period between external retriggers; therefore, it cannot be accurately
controlled. The board ignores external triggers that occur while it is acquiring data. Only
external retrigger events that occur when the board is waiting for a retrigger are detected and
acted on.
To select externally-retriggered scan mode, use software to specify the following parameters:
• The dataflow as Continuous.
• Triggered scan mode as enabled.
• The retrigger source as an external digital (TTL) trigger.
• The number of times to scan per trigger or retrigger (also called the multiscan count).
Notes:
If you are using an external trigger source as the initial trigger and want to retrigger
externally, specify the same trigger source as the retrigger. For example, if you are using an
external digital (TTL) trigger as the initial trigger, specify the external digital (TTL) trigger as
the retrigger.
An A/D Trigger Out signal is provided for your use. This signal is high when the A/D
subsystem is waiting for a trigger and low when a trigger occurs. In externally-retriggered
scan mode, this signal stays goes low when the trigger occurs and stays low until the desired
number of samples have been acquired, then goes high until the external retrigger is
generated.
Triggers
A trigger is an event that occurs based on a specified set of conditions. DT3010 Series boards
support a number of trigger sources and trigger acquisition modes, described in the following
subsections.
Trigger Sources
DT3010 Series boards support the following trigger sources:
• Software trigger
• External digital (TTL) trigger
• Analog threshold trigger
This subsection describes these trigger sources in more detail.
Software Trigger
A software trigger event occurs when you start the analog input operation (the computer
issues a write to the board to begin conversions). Specify the software trigger source in
software.
Содержание Data Translation DT3010 Series
Страница 2: ...DT3010 Series UM 16866 V User s Manual Title Page ...
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Страница 15: ...About this Manual 14 ...
Страница 16: ...15 1 Overview Features 16 Supported Software 18 Accessories 19 Getting Started Procedure 21 ...
Страница 23: ...Chapter 1 22 ...
Страница 24: ...Part 1 Getting Started ...
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Страница 37: ...Chapter 2 36 ...
Страница 49: ...Chapter 3 48 ...
Страница 91: ...Chapter 4 90 ...
Страница 102: ...Part 2 Using Your Board ...
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Страница 147: ...Chapter 6 146 ...
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Страница 160: ...159 8 Calibration Calibrating the Analog Input Subsystem 161 Calibrating the Analog Output Subsystem 169 ...
Страница 176: ...175 9 Troubleshooting General Checklist 176 Technical Support 178 If Your Board Needs Factory Service 179 ...
Страница 181: ...Chapter 9 180 ...
Страница 193: ...Appendix A 192 ...
Страница 213: ...Appendix B 212 ...
Страница 231: ...Index 230 ...