Recalibration Intervals Costed across a Five Year Service Fleet
Risk-adjusted calibration cycles combined with quarterly field verification reduce 5-year fleet costs by 23 percent while holding out-of-tolerance risk below 2.5 percent.
In-Situ Verification
Functional Validation
Testing procedures performed while an instrument remains in its installed position confirm its operational accuracy without disrupting the process. This in-situ verification ensures that the sensor performs within its specified limits under actual operating conditions. This method reduces the need to remove and transport delicate equipment to a laboratory.
Operational Procedure
Verification technicians apply known physical or electrical inputs to the sensor to check its output response. For example, a temperature transmitter might be checked using a dry block calibrator or a reference thermometer inserted into an adjacent thermowell. This procedure verifies the sensor and its associated wiring without dismantling the system.
Reference Comparison
Reference measurements require comparing the output of the sensor against a portable reference standard that has a higher level of accuracy. The reference standard must have a current calibration certificate to ensure traceability to international standards. Any deviation between the two readings is recorded to determine if the sensor remains within its allowed tolerance.
If the drift exceeds the specified limit, the technician must schedule a full calibration or replace the sensor to prevent process errors.
System Diagnostics
Automated diagnostic routines built into modern smart transmitters can perform internal electronic checks to detect sensor drift. These diagnostics monitor circuit impedance and supply voltage to identify deterioration before a complete failure occurs. This continuous assessment helps maintain the integrity of process control loops by alerting operators to potential issues.