In-Situ Calibration: Methods And Pitfalls Of Thermal Mass Flow Meter Sensor Field Validation

By Matthew J. Olin, President & CEO, Sierra Instruments, Inc.

Mid-to-large size facilities and campuses inevitably have hundreds of flow instruments to monitor, maintain, and repair. For a reliability engineer, ensuring that all instrumentation meets ISO 9000 or similar standards is a time-consuming responsibility. These standards mandate that precision instrumentation needs to be checked (validated) or recalibrated as often as once a year. Sensor elements can become dirty, plugged, or drift over time. The resistance and capacitance of electronic components also degrades, leading to changes in sensitivity or drift.