Historize a tag

Historizing a tag tells MACHHUB to record its values over time so you can chart and export them later in the Historian.

Enable history

1. Open Namespace → Manage and select a tag.
2. In the tag-details pane, open the Historize dialog.
3. Toggle history on and choose a Type:
   • On Change (event) — record a point each time the value changes.
   • Time Series (timeseries) — record on a fixed schedule.
4. For Time Series, set the Sampling Time and unit (second / minute / hour).
5. Set a Retention Period and unit (day / week / month / year).
6. Save. The tag now shows a history icon in the tree.

The Historize dialog — Time Series with sampling and retention.

Select a tag → Historize → toggle on → Time Series + sampling/retention → Save.

On-change vs. time series

flowchart TB
  V["Tag value updates"] --> Q{"Historize type?"}
  Q -->|On Change| E["Store a point only when the value changes"]
  Q -->|Time Series| S["Store a point every sampling interval"]
  E --> H[("Historian")]
  S --> H

• Use On Change for state-like or sparse signals.
• Use Time Series for continuous signals you want sampled at a steady rate.

Retention

The retention period controls how long history is kept before old points are pruned. Choose a period that matches your analysis and compliance needs.

Next

• View and export history → Historian
• Query history in code → SDK → Historian
• Concept → Historian