You can copy the full archive of one PI point into another point on the same PI Data Archive without an Excel export and import. If the old tag is being retired, rename it. If both tags must exist, copy the point definition in PI System Management Tools (SMT), move the new point to an unused point source, map the old tag to the new tag with an AF expression analysis, backfill the period you need, then stop the analysis.
Do you need a rename or a second tag with history?
A freshly created point that trends only a Pt Created event is empty by design. The archive stores events against the point's internal ID, not its name. A point copied in Point Builder gets a new ID and no events. A renamed point keeps its ID, so it keeps every archived value.
| Requirement | Method | History result | Old tag afterwards |
|---|---|---|---|
| Old name disappears, data continues under a new name | SMT > Points > Point Builder > Rename | All history stays, no copy needed | Gone (same point, new name) |
| Both tags must exist, old tag keeps collecting | Copy point + AF expression analysis + backfill | Copied for the backfilled range | Unchanged |
| New tag must keep mirroring the old one live | Same as above, leave the analysis running | Backfilled range plus new events | Unchanged |
When both approaches would work, rename. It moves no data, cannot drop events, and needs no AF configuration. Before renaming, find every consumer of the old name (displays, AF attributes referencing by name, reports, interface output points) because name-based references break.
Check: decide whether the old tag must keep receiving production data. If not, rename and stop here.
How do I create the target point in PI SMT Point Builder?
SMT installs with the PI Data Archive and is normally present on engineering clients too.
- Open SMT, select the Data Archive, and go to Points > Point Builder.
- Load the existing (input) tag.
- Overwrite the name field with the new tag name and save it as a new point. Point Builder creates a second point carrying the same attributes.
- Leave point type, digital state set, engineering units, and zero/span identical to the source tag. A type mismatch (for example a digital source into a float target) makes the analysis write fail or convert values.
Check: search for the new name in Point Builder and confirm it exists with the same point type as the source. Its trend should show only the Pt Created event.
Why must the point source change before any data is written?
The copied point inherits the point source and location codes of the original. If the original belongs to a data-collection interface, that interface now sees a second point addressed to the same device item and starts writing live production data into the new tag. That live data then interleaves with the backfilled history and corrupts the copy.
| Setting | Where | Effect of leaving it unchanged | Set it to |
|---|---|---|---|
| Point source | Point Builder, General tab | Interface picks up the point and writes live values | A value no interface scans |
| Location codes / instrument tag | Point Builder, Classic tab | Irrelevant once point source is unused | Leave as is or clear |
| Scan / compressing flags | Point Builder | Backfilled events older than the snapshot bypass compression anyway | Leave as copied |
| Data security | Point Builder, Security tab | Analysis Service write is denied | Grant write to the account running PI Analysis Service |
Check: wait a few scan cycles and confirm the new tag's snapshot is still Pt Created. Any fresh value means an interface still owns the point.
How do I map the old tag to the new tag with an expression analysis?
Separate tag faults from binding faults here. Tag faults (wrong type, blocked security, active point source) live on the PI point and are fixed in SMT. Binding faults live in AF: an attribute pointing at the wrong tag, or an output left unmapped.
- In PI System Explorer, create or pick an AF element.
- Add an input attribute with a PI Point data reference to the old tag.
- Add an output attribute with a PI Point data reference to the new tag.
- Create an Expression analysis on the element. Make the expression the input attribute itself (a straight pass-through, no math).
- Map the expression output to the output attribute.
- Set scheduling to event-triggered on the input attribute, so the analysis evaluates once per archived event of the old tag rather than on a clock.
- Use the preview/evaluate function to confirm the output equals the input value.
Check: the output attribute resolves to the new tag name (not a red, unresolved reference), and the preview returns a value, not Calc Failed.
How do I backfill the history, and can the SourceTag attribute do it instead?
- Enable the analysis.
- Right-click it and start a backfill. Choose the start time at or before the first event you want copied and the end time at now.
- Use the option that writes into the empty range. The delete-and-recalculate option is unnecessary on a new, empty tag.
- Watch backfill progress in the analysis management view until it completes.
- Stop (disable) the analysis if the new tag must hold history only. Leave it running if the new tag should keep mirroring the old one.
Because every backfilled event is older than the new tag's snapshot, the Data Archive treats them as out-of-order writes that skip exception and compression. With event-triggered scheduling, you get one output event per archived input event. Backfill writes only succeed where an archive file covers the timestamp, so confirm the archives spanning the requested range are registered.
The SourceTag point attribute does not copy history. It is read by the subsystem or interface that owns the point, for example an interface output point that forwards new values of the source tag to a device, and it only acts on new snapshot events. It has no mechanism to walk the archive backwards, so it produces nothing for past periods.
| What the trend shows | Cause | Fault type | Fix |
|---|---|---|---|
Only Pt Created after backfill |
Output unmapped or write denied | Binding / security | Map output; grant write to the Analysis Service account |
| History plus unexpected live values | Point source still active | Tag | Change point source, delete stray events |
Calc Failed events |
Input returned a bad/system state or type mismatch | Tag / binding | Match point types; check input attribute reference |
| Gaps in early period | Backfill start too late or no archive covering that range | Configuration | Rerun backfill with earlier start; register archive |
| Fewer events than source | Periodic schedule used instead of event-triggered | Binding | Switch to event-triggered, rerun backfill |
Check: the backfill status shows complete and the analysis is in the state you intended (stopped or running).
How do I prove the new tag matches the old one end to end?
- Open both tags in SMT Archive Editor for the same start and end time.
- Compare the first and last event timestamps and values in each tag.
- Compare the event count over the full range. Event-triggered backfill should give matching counts, plus the single
Pt Createdevent on the new tag. - Spot-check a busy period and a period containing digital system states from the source.
- Trend both tags overlaid across the whole range and confirm the lines coincide with no breaks.
- With the analysis stopped, wait past the source's normal update interval and confirm the new tag receives no further events while the old tag keeps updating.
Frequently asked questions
How do I copy PI point history without exporting to Excel?
Copy the point in SMT Point Builder under a new name, change its point source to one no interface scans, then map the old tag to the new tag with an event-triggered AF expression analysis and backfill the required range. Stop the analysis when the backfill completes.
How do I rename a PI tag and keep its history?
Load the tag in SMT > Points > Point Builder and use Rename. The archive is keyed to the point ID, so all history stays with the renamed point; update any displays or references that use the old name.
Does the PI SourceTag attribute backfill historical data?
No. SourceTag is consumed by the interface or subsystem owning the point and reacts only to new snapshot events, so it cannot recreate past values. Use an AF analysis backfill for history.
How do I check that a backfilled PI tag matches the source tag?
Open both tags in SMT Archive Editor over the same range and compare first/last events and event counts; the new tag should match plus one Pt Created event. Then confirm the new tag stops updating once the analysis is disabled.