Flowmeter verification Flowmeters operating based on a Coriolis, electromagnetic, ultrasonic, vortex, or thermal measuring principle do not have moving parts subject to wear. But they can have problems that require recalibration, including failure of an internal part or degradation because of temperature effects on electronics — or corrosion, clogging, or coating buildups in the flowmeter body. Flowmeter faults during operation that go undetected by diagnostics can result in an unexpected plant shutdown, product loss, or a reduction in product quality. Process manufacturing and other industrial facilities must often provide documented evidence of flowmeter performance to maintain compliance with various regulatory agencies, ensure product quality, and optimize production. Often, this is achieved with “wet calibrations,” in which the flowmeter is removed from the process and taken to a lab for formal test- ing and certification or re-calibration. After calibration, the instrument is then sent back to the facility to be reinstalled. Using HART helps plants accomplish these tasks through built-in verification techniques. The flowmeter’s transmitter electronics run an onboard diagnostics program during which all relevant components of the instrument are checked to confirm and document that the instrument is still in calibra- tion and none of the meter components have drifted outside original tolerances. Valve maintenance Valves account for up to 90% of safety failures in a facility and 20 to 50% of maintenance turnaround time when using preventative maintenance schedules. Using diagnostic data provided via HART, operators can periodically review valve signatures to find early indicators of wear or damage before a failure occurs. A valve signature is a chart that plots two diagnostic parame- ters against each other, such as the air pressure and the valve travel distance. The valve signatures are checked periodically and compared to earlier signature data to see how the performance has changed over time. PHOENIX CONTACT 7