26 lines
1.4 KiB
Markdown
26 lines
1.4 KiB
Markdown
## Measurement settings
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### Measurement Modes
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In the **normal** measurement mode, the `cpdctrl` asks the voltage measurement device
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for a new value in regular intervals.
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This has the advantage that the LED state is always correctly synced with the voltage values,
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however, the intervals might not be consistent since a software timer is used, which
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is very inconsistent below 500ms.
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The signal-to-noise ratio might also not be good, since the device will spend a lot of time not measuring the voltage.
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The **buffer** mode fixes this, by using voltage measurement device's internal data buffer and timing capabilities.
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This allows for lower and very consistent intervals, but the timing of the LED value might be off
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by a few tens of milliseconds, since these are still controlled by the lab computer.
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Since this should not be big problem, **buffer mode should be preferred**.
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### Data Flushing
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Measurements can be performed over many hours or multiple days.
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To make sure that unforeseen accidents like Windows Updates do not ruin the entire measurement,
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the data can be continuously written to the disk.
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To enable this feature, set `Flush After` to a non-zero value (in the Measurement Settings tab).
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After \<Flush After\> number of datapoints are recorded, they are written to the cache directory
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as serialized numpy array.
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When the measurement is finished, all partial arrays are loaded again and the complete data
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can be saved as `csv` or serialized numpy array (`.pkl`).
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