Fluke RPM4 manual Maintenance Adjustments and Calibration, Principle

5. MAINTENANCE, ADJUSTMENTS AND CALIBRATIONS

5.MAINTENANCE,

ADJUSTMENTS AND CALIBRATION

5.1OVERVIEW

RPM4 was designed for maintenance free operation. No maintenance is required other than:

•Regular AutoZeroing of quartz reference pressure transducer(s) (Q-RPT) (see Section 3.5.1).

•Periodic calibration of Q-RPT(s) (see Section 5.2).

•Adjustment of the on-board barometer, if present (see Sections 5.3).

This section provides information on maintenance, adjustment and calibration procedures, and recommended overhaul procedures.

RPM4 is a sophisticated pressure measuring instrument with advanced on-board features and functions. Before assuming that unexpected behavior is caused by a system defect or breakdown, use this manual and other training facilities to become thoroughly familiar with RPM4 operation.

For rapid assistance in specific situations see Chapter 6 for troubleshooting information.

RPM4 is covered by a limited one (1) year warranty. Unauthorized service or repair during the warranty period is undertaken at the owner’s risk and may cause damage that is not covered under warranty and/or may void the warranty. For warranty service, contact a DHI Authorized Service Provide (see Table 29).

5.2CALIBRATION OF QUARTZ REFERENCE PRESSURE TRANSDUCERS (Q-RPTS)

5.2.1 PRINCIPLE

RPM4 is equipped with one or two quartz reference pressure transducers (Q-RPTs) used for low uncertainty pressure measurement.

To calibrate a Q-RPT, pressures from a reference standard are applied to the Q-RPT at ascending and descending pressure increments over the range. The recommended pressure sequence for a calibration varies depending on whether the Q-RPT is of Standard or Premium class (see Section 1.2.2.1). The pressure defined by the standard and the corresponding Q-RPT readings are recorded at each point. After all of the pressures have been applied and recorded, adjustments are made to fit the Q-RPT pressure readings to the standard. Fitting the readings means performing a linear regression to arrive at the lowest value of the residuals of errors of the Q-RPT relative to the standard. The Q-RPT output is adjusted by user settable coefficients: PA (an adder or offset) and PM (a multiplier or span set) (see Section 5.2.1.1).

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