User guide: Troubleshoot by symptom
Diagnose using the affected page, update times, device quality and event records.
The page opens but values are unavailable
Page access, realtime connection, PLC connectivity and Tag quality describe different stages.
- Check services and data infrastructure in System Status, then inspect device connection and collection in Devices.
- Add the target Tag in Tag Diagnostics and check enabled state, address, type, quality and timestamp.
- If the Tag is valid but the screen remains empty, check page references, the current release, menu target and page permissions.
Remote data, alarms or trends are unavailable
Inspect the remote site in the local Sites page.
- Check the remote address, connection identity, selected capabilities and device scope.
- Open remote screens, alarms or trends separately to distinguish a connection failure from an unavailable capability.
- Local rules using remote Tags also require local definitions and service input scope. A visible device catalog does not enable every consumer.
Historical curves are empty or have gaps
Historical queries depend on archiving and records actually saved within the selected period.
- Check the time range, timezone, device filter and selected series.
- Check Tag archiving, sampling mode and interval, followed by Trend service status and retention.
- Invalid quality or unavailable collection can leave no valid points. Gaps reflect recorded data; a wider interval can help locate the affected period.
A write result is unconfirmed
Acceptance, protocol completion and readback confirmation are different outcomes.
- Retain the request ID, timestamp, target and returned status, then find the operation in Event Records.
- Inspect subsequent quality and values in Tag Diagnostics. Other operations may change the value, so compare timestamps.
- If the outcome remains unknown, reconcile device state and request records before repeating an operation.
Scripts or external APIs are unavailable
Developer interfaces and administration pages have distinct permissions and runtime prerequisites.
- For Python, check the Script service, active project version, enabled events and actions, and run records. After adding a dependency, confirm the installation result and check its import in the same project.
- For IO State API, check published Profile revision, Access Key, scopes and signal range. A connection ticket is single-use.
- For the page SDK, check that the screen is opened through a host menu, its declared reads/writes and user permissions. Use the relevant chapter’s errors and status descriptions.
