Method
For each timestamp except the last, the current reading classifies the full interval to the next timestamp as below, inside, or above the limits. Consecutive intervals in the same outside zone form one event. The last reading is reported but contributes no time because its closing boundary is unknown.
Interpretation
The result is sensitive to sampling rate and the hold/interpolation convention. A recorder may have crossed a limit between readings. Verify sensor range, quality flags, limit revision, equipment mode, and whether linear interpolation or higher-frequency evidence is required.
Worked example and limitations
The sample reconstructs 4.5 hours: 1.5 above 80, 1 below 40, and 2 inside. The two adjacent high readings form one 1.5-hour event. Limits come from the user; ReliabilityBench does not determine a safe, regulatory, OEM, alarm, or trip value.