Power Chart flickers / shows "No Trend Data Source"

Ignition
,
1

  • Power Chart keeps alternating between drawing the trend and showing "No Trend Data Source available. Please add Tags from the Tag Browser panel." The pen stays configured and checked. Happens in both Designer preview and browser sessions.

    Environment:
    Ignition 8.3.4 (b2026030309), Windows 10 laptop, Trial mode - SQL Server 2022 + KEPServerEX running on the same machine.

    Tag Historian:

  • database provider → MSSQL connection (status VALID).

  • Perspective view: coordinate container, Power Chart, single pen

  • Pen source: histprov:MediHistorian:/drv:ignition-ut-ltp-1511:default:/tag:line/blending/blenderrpm - Pen is saved in view.json (verified via project export), not session-only

    Data checks done:

  • system.tag.queryTagHistory() from Script Console returns rows consistently (100 rows for last 10 min) while the chart is flickering.

  • sqlth_te has the tag entry, sqlt_data partition has rows flowing.

  • Same behavior after rebuilding the Power Chart fresh and re-adding the pen

2

I would guess that the history queries are running slower than the realtime poll rate. Slow that way down for troubleshooting.