Compare signals in Explore and export the result

Worked example

Example: temperature while the furnace changes state

Use fictional furnace temperature and status attributes. A chart can show how a measurement changes around a state transition without first building a separate report.

Procedure

Follow the task in order

1. 1
   Check prerequisitesHistorical reads require eligible measurements captured by UNS Archiver into QuestDB, mappings, a reachable API and your read permission. A live MQTT value does not prove history exists. Use compatible component releases; complete bounded Raw Excel collection requires Controller 2.2.15 and API Global 4.1.20 or newer.
2. 2
   Open one attributeIn Unified namespace select the Attribute and choose Explore attribute. Check its complete topic, unit, last observation time and Data shape strip. This opens one concrete topic. Asset history is a separate identity-based window.
3. 3
   Choose the time windowUse a live range for a moving window or Custom for fixed bounds. Zoom or shift the time axis to investigate a period. For an old or stopped producer, choose the time when it actually published; the default recent window may accurately be empty.
4. 4
   Add relevant seriesChoose Add series and select another permitted signal or supported Table column. Numeric series use the chart; string/status data uses transition lanes. Key/value or Table data needs declared columns or response mapping. Aligning timestamps helps inspection but does not establish causality or perform a business join.
5. 5
   Inspect sampling and aggregationCheck Last, Avg, Min, Max or Sum where supported, plus Detail. A minute average differs from raw readings. Counter handling depends on the source metadata; an already calculated delta must not be differentiated again. Preserve the unit and data-shape context when interpreting a result.
6. 6
   Choose history deliberatelyUse History sources in the toolbar. Automatic uses compatible registered active and retained sources where safe. When sources cannot be combined safely, read the explanation and explicitly choose the current source or inspect a retained source separately. Selecting one source can omit earlier history; it does not repair or migrate a table.
7. 7
   Use the available spaceHide table gives the chart more room. When chart and table are both shown, drag the divider between them to adjust the chart height. Restore the table to inspect timestamps and values. Layout changes do not alter stored measurements.
8. 8
   Inspect the query and save a viewOpen SQL/query details for a supported historical read to inspect the actual query. Views → Save stores a reusable selection and settings; it does not freeze returned data or grant another user access. Use Save as for another analysis. Reopen and check time mode, series, sources and permissions. With Controller/UI 2.2.10, Save on a view owned by another user opens Save as for your own Private copy; sharing that copy remains a separate decision.
9. 9
   Export the intended dataChoose the chart export for its current query result or Raw Excel for source observations. Raw gathers bounded, non-overlapping time windows without raising the API row limit; progress shows series, readings, requests and covered time. Cancel stops collection without downloading a partial workbook. Incomplete or unsupported responses block the download with an explanation. Inspect wide/long sheets and metadata for mode, source, time window and filters. Repeated timestamps and identical observations are retained; UTC text preserves fractional source precision while Excel Date cells have millisecond precision. Direct QuestDB SQL requires separate database access.

Expected result

What you should have

Boundaries

Important boundaries

• A failed refresh must not be interpreted as zero consumption or proof that old displayed values are current. Check the warning, last successful read and Services diagnostics.
• No archived values means no returned rows for this request. Check publication time, selected table, archival eligibility, retention and permissions before changing the source.
• Query limits and export limits still apply. Saved views and shared links are selections, not immutable evidence snapshots or access grants.
• Raw is bounded, not unlimited: collection and workbook safeguards still apply. A timestamp group too dense to split safely is rejected rather than silently dropping or deduplicating readings. Use a smaller range or another authorized extraction path when a bound is reached.

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