Greyline Instruments PDFM 5.1, User Manual

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PDFM 5.1 Portable Doppler Flow Meter
Does the PDFM 5.1 require periodic recalibration?
PDFM 5.1 calibration does not drift over time. The solid state sensor has no moving parts to wear and
affect calibration. The Doppler flow technique generates an ultrasonic signal proportional to the velocity
of flow. All Greyline timing/counting circuits use crystal-controlled frequency references to eliminate
any drift in the processing circuitry.
ISO 9000 or similar quality management systems may require periodic and verifiable recalibration of
flow meters. PDFM 5.1 Doppler Flow Meters may be returned to Greyline for factory calibration and
issue of a new NIST traceable certificate. Refer to the ‘Product Return Procedure’ section of this manual
for return instructions.