Push or update a single value into a PI tag via PI Web API for integration testing
domain: aveva.com · 6 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Resolve the target WebID the same way as for reads via GET /piwebapi/points?path=... or /piwebapi/attributes?path=...
Build a JSON body with the value and optional timestamp, e.g. {"Timestamp": "2026-07-09T12:00:00Z", "Value": 888}; omit Timestamp to write at the current time
POST the JSON body with Content-Type: application/json to /piwebapi/streams/{webId}/value
Use a REST client that supports POST bodies (curl, Postman, PowerShell Invoke-RestMethod)
To write multiple values across tags in one call, POST to /piwebapi/streamsets/recorded or bundle requests via /piwebapi/batch
Verify the write by re-issuing GET /piwebapi/streams/{webId}/value and confirming the returned Timestamp/Value match what was sent
Known gotchas
The calling identity needs Data Write access on the target point/attribute — a read-only service account gets 401/403 on the write even though GET works fine
Omitting Timestamp inserts at the PI Web API server's clock time, not the sensor's, which can create out-of-order or duplicate-suppressed values
This writes real values into a live historian — always target a test/sandbox PI point for integration testing, never a production safety/alarm tag
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