Acquisition Sub-System
The acquisition sub-system configures the size of the waveform record, the length of time that corresponds to the overall waveform record, and the acquisition start time. The configurable acquisition sub-system properties include:
- IviScope Acquisition Start Time
- IviScope Horizontal Minimum Number of Points
- IviScope Horizontal Time Per Record
You specify the minimum number of points they require the oscilloscope to acquire with the IviScope Horizontal Minimum Number of Points property. The IviScope Horizontal Time Per Record property specifies the length of time that corresponds to the overall waveform record. You specify the length of time from the trigger event to the first point in the waveform record with the IviScope Acquisition Start Time. If the value is positive, the first point in the waveform record occurs after the trigger event.
All of the acquisition properties can be set individually or they can be set as a group with the IviScope Configure Acquisition Record VI.
In addition, the acquisition sub-system includes two read-only properties:
The IviScope Horizontal Record Length property returns the actual number of points in the waveform record. The IviScope Horizontal Sample Rate property returns the effective sample rate of the oscilloscope.
The IviScope class driver defines separate properties for the minimum record size you request and the actual record length. Typically, oscilloscopes change the record length dynamically when the acquisition type changes. For example, when you change the acquisition type from normal to envelope, many oscilloscopes reduce the record length by half. When you change the acquisition type, the instrument driver uses the value held in the IviScope Horizontal Minimum Number of Points property to check that the new record length is equal to or greater than the minimum record length you require.