Check historian readings against signal quality and limits
Review timestamps, quality flags, engineering units and independent limits in an exported process historian dataset.
How this check works
Inputs and matching rules
Use the following exports: Historian readings, Independent operating limits.
- Use finite dot-decimal values and ISO 8601 timestamps with Z or an explicit UTC offset.
- Only explicit Good quality is admissible; Bad, Uncertain, missing and numeric encodings are excluded.
- All duplicate tag/timestamp readings are excluded, even when their values agree.
- Limits are optional, unique by exact tag, and inclusive. Units must match exactly; no automatic unit conversion.
- Missing, invalid or duplicated limits block comparison for the affected tag.
Read the evidence
For a pressure tag, compare a Good reading only to a reference expressed in the same unit. A value with an Uncertain flag should be reviewed before concluding it is an operating-limit breach.
What the result can establish
Sampled export checks only. No live alarms, duration estimates, equipment control, engineering certification or safety approval.