SEFRAM BK Precision DAS30, Руководство пользователя

Страница: 38 / 84

38
When all blocks are full, any new data acquisition will shift the previous blocks from the N position into the N-1 position;
the 1
st
block will be lost.
The new data acquisition will take the place of the last block.
7.4 Trigger position
The data acquisition into a memory block relies on the concept of « circular buffer »:
•
the buffer is filled from the starting condition on
•
the buffer is filled as long as the stop condition is not valid; when the buffer is full, it fills from the initial position of
the buffer zone (block)
Thus, the memory block always contains the last N samples.
The operator can select when the samples in buffer will be frozen; to do so, you will select a delay between the trigger
start and the beginning of the effective buffering.
This delay may be positive or negative: thus, buffered samples may be before, after or on both sides of the start moment.
You can also not inhibit the trigger: you will be able to test the trigger during the pre-trigger phase, in case the trigger
should happen before the end of this phase. In case of repetitive signals, the trigger should be inhibited.
Delay to memory input: -50% Delay to memory input: +50% from the 1
st
position of buffer from the 1
st
position of
buffer
7.5 Double Trigger mode
In this mode, you will use a start trigger and a stop trigger.
Measurements between these two triggers shall be registered.
Data acquisition will stop automatically: - when the stop condition is valid, or - when the memory block is full.
Figure 7.2
7.6 Recording
Start data acquisition by pressing after pressing .
At the top left of the screen appear:
•
the number of the pending block, if required
•
the current sampling rate
•
the status of data acquisition (waiting for trigger, filling xx%
…
)
•
the opening of a save file, if required
•
a bargraph showing the percentage of data acquisition made and the percentage of data acquisition displayed
Pressing stops the pending data acquisition process.