Operating problem
Review what each signal represents and when it was obtained before fitting a model or adjusting control logic.
Review units, timing, calibration status, interruptions, filters and maintenance records. Compare with other available measurements.
A complete history can contain periods that do not describe the process. Identify which intervals are usable for diagnosis and which require verification.
Interpretation requires reviewing equipment conditions and plant procedures. This page guides diagnosis and does not define emergency actions.
Review how to approach the problemKnowledge
Instrumentation and data 3 min
A signal can respond to process variations and maintain a reasonable appearance while the instrument's physical condition changes slowly. Build-up, drift, loss of calibration or an installation condition can shift…
