ScopeFetchRelativeTo Enumeration
- Updated2023-09-06
- 2 minute(s) read
ScopeFetchRelativeTo Enumeration
Specifies the position to start fetching within one record.
Namespace: NationalInstruments.ModularInstruments.NIScope
Assembly: NationalInstruments.ModularInstruments.NIScope.Fx45 (in NationalInstruments.ModularInstruments.NIScope.Fx45.dll) Version: 2023
Syntax
public enum ScopeFetchRelativeTo
Public Enumeration ScopeFetchRelativeTo
Members
Member name | Value | Description | |
---|---|---|---|
Start | 482 | Fetches data starting at the first point sampled by the digitizer. For devices that support continuous acquisition, you must fetch relative to Now or relative to Start before the trigger occurs. The number of points available when fetching relative to start may be extremely large because there may be an infinite number of pretrigger samples if the trigger never occurs. Furthermore, the pretrigger points are sampled into a circular buffer, so the data at the start may be overwritten. If the data is no longer available for fetching, the fetch method throws an exception. | |
Trigger | 483 | Starts fetching at the first posttrigger sample, which is useful for fetching a small number of points near the trigger. | |
Pretrigger | 477 | Fetches data relative to the first pretrigger point requested. | |
Now | 481 | Starts fetching data at the last sample acquired. Therefore, you must use a negative offset when fetching relative to now. This option is useful for configuring an infinite acquisition (one that never triggers) and occasionally fetching the most recent data. | |
ReadPointer | 388 | Specifies the read pointer value. When you initiate a new acquisition, the read pointer is set to 0. At this point, fetching relative to the read pointer is equivalent to fetching relative to start. After every fetch, the read pointer is incremented to be the sample after the last sample retrieved. Therefore, you can repeatedly fetch relative to the read pointer for a continuous acquisition program. |