Instrumentation and SCADA · Maintenance and Troubleshooting
What Is an Instrument Calibration Check?
A calibration check tests instrument response against a known reference.
The check may confirm the instrument or show that adjustment is needed. References must be in date, clean, and handled correctly. The plant procedure sets acceptance limits.
A standard solution is expired. The operator replaces it before deciding whether the sensor passed or failed.
A reference is only useful when its value is known and suitable for the instrument range. Protect standards from heat, dirt, evaporation, and cross-contamination. Allow the sensor and reference to reach the required condition before judging the result. If the check fails, repeat only as the procedure allows. Repeating a test until it passes can hide a real problem. Tag or remove an unreliable device when required so others do not use its value unknowingly.
Do not repeat failed checks until one happens to pass.
Key point: References must be in date and clean. Repeating a failed check until it passes can hide a real problem.
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Wastewater Instrumentation, SCADA, and Process Control Fundamentals
This page comes from the course. It covers plant instruments, signals and control, flow, level, pressure and water-quality measurement, SCADA and alarms, and instrument maintenance, one step at a time, with short knowledge checks and a certificate of completion.
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