Measures Check

Use these questions to prepare for the Kanoa Ops certification exam.

Why does a measure store a summary instead of every raw sample?

High-frequency signals would generate millions of rows a day. A measure collects values over a window and writes one record with the mean, standard deviation, min, max, sample count and control limits, keeping the shape of the signal at a fraction of the storage. See Measures.

What are the two ways to define a measure's collection window?

By sample count (maxSampleCount) or by duration (maxSampleDurationSecs). A record is written when the window completes. See Configure a Measure.

What does enabling the Tag option on a measure create, and what must you connect?

A measure UDT instance in a measures folder under the asset's tags. Its value tag must be pointed at the source signal, and enabled set to true, before it starts collecting. See Configure a Measure.

Why does each measure record keep its sample count?

So later roll-ups across many windows, lines or sites can be weighted properly, instead of treating every window as one data point. See Measures.

What does a Large Gap in the Gap Analysis table usually mean?

Collection stopped or stalled: the tag was disabled, the source disconnected, or the gateway restarted. Check gaps before using the data for reporting. See Analyze Measures and SPC.

What is needed to run SPC checks on a measure?

A Quality license, a quality attribute with tolerances linked to the measure, and spcCheckEnabled set to true on the measure tag. Violations set outOfControl, are listed in ruleViolations, and appear in the notifications widget. See Analyze Measures and SPC.