What is the default method of data storage for an analog value that has been configured to historize?

The default method of data storage for an analog value configured to historize is that a value is stored for the attribute when the engine scans and the attribute's value or quality has changed. This approach ensures that only meaningful changes in data are recorded, optimizing storage and allowing for more efficient data processing.

When the system detects a change in either the value or the quality of the attribute during a scan, it triggers the storage process. This is advantageous because it reduces data redundancy and captures only significant events or variations in the analog value, thereby increasing the efficiency of data retrieval and analysis.

In contrast, other methods, such as storing a value at regular intervals regardless of changes, would lead to unnecessary data accumulation and might make it difficult to extract relevant insights from the dataset. Moreover, not storing data when the quality is low is part of the overall data integrity approach, ensuring that only reliable and accurate data is kept, but it doesn't define the default storage method when conditions for storing a value are met. Hence, option B accurately describes how AVEVA Historian manages data storage for historized analog values.