Resolution (values spaced every X ms) (wwResolution)

In retrieval modes that use cycles, the resolution is the sampling interval for retrieving data, that is, the length of each cycle.

The number of cycles, therefore, depends on the time period and the resolution:

number of cycles = time period / resolution

The number of actual return values is not always identical with this cycle count. In "truly cyclic" modes (Cyclic, Interpolated, Average, and Integral), a single data point is returned for every cycle boundary. However, in other cycle-based modes (Best Fit, Minimum, Maximum, Counter, and ValueState), multiple or no data points may be returned for a cycle, depending on the nature of the data.

Note: The rowset is guaranteed to contain one row for each tag in the normalized query at every resolution interval, regardless of whether a physical row exists in history at that particular instance in time. The value contained in the row is the last known physical value in history, at that instant, for the relevant tag.

Instead of specifying a resolution, you can specify the cycle count directly. In that case, the resolution is calculated based on the cycle count and the query duration. For more information, see Cycle count (X values over equal time intervals) (wwCycleCount).

This option is relevant in the following retrieval modes:

• Cyclic retrieval

• Interpolated retrieval

• Best fit retrieval

• Average retrieval

• Minimum retrieval

• Maximum retrieval

• Integral retrieval

• Counter retrieval

• ValueState retrieval

• RoundTrip retrieval

For delta retrieval, you can achieve similar results by using a time deadband. For more information, see Time deadband (wwTimeDeadband).