Fluke RPM4 manual PA and PM Coefficients, AS Received and AS Left Data

RPM4™ OPERATION AND MAINTENANCE MANUAL

The calibration process is performed independently on each Q-RPT to arrive at its optimal fit.

CalTool for RPTs software provided with the RPM4 supports the calibration process of RPM4 Q-RPTs. CalTool and its documentation are provided on a General Accessories Disk with a new RPM4 and can be downloaded from www.dhinstruments.com. Most users should use CalTool software to assist in the calibration of RPM4.

RPM4 is delivered with an interactive Q-RPT calibration utility that steps the operator through the complete Q-RPT calibration procedure including applying the necessary pressures, collecting data automatically, calculating new PA and PM values, previewing the results of the new calibration and activating the results of the new calibration (see the CalTool for RPTs manual on the General Accessories Disk). RPM4 also provides complete front panel and remote access to Q-RPT calibration parameters so that Q-RPT calibrations can be performed without using CalTool software (see Section 5.2.8).

5.2.1.1PA AND PM COEFFICIENTS

The coefficients used to adjust Q-RPT readings are designated PA (an adder or offset) and PM (a multiplier or span set). The coefficients affect the Q-RPT reading following:

Corrected reading = (uncorrected reading • PM) + PA

PA is expressed in units of pressure (always the SI unit, Pascal). PM is dimensionless.

Each Q-RPT has its own unique PA and PM values. The PA and PM values currently in use can be viewed and edited from the front panel in the CAL function (see Section 5.2.7). PA and PM values are automatically edited when CalTool software results are activated.

As editing PA and PM values will change Q-RPT calibration, they should only be edited by qualified personnel as part of the calibration process. Caution should be taken to avoid accidental editing and a security system is available to prevent access (see Section 3.5.5.5). Incorrect editing of PA and PM values can cause out of tolerance measurements.

A new RPM4 is delivered with PA and PM values set to zero and 1 for all ranges. This does not mean that the RPM4 has not been calibrated. In the original factory calibration, privileged factory coefficients are used for calibration with the user PA and PM set to zero and 1.

5.2.1.2AS RECEIVED AND AS LEFT DATA

Frequently, calibration procedures require that as received and as left data be reported. The necessary information to report as received and as left data on the calibration of RPM4 Q-RPTs can be obtained in several ways.

When the RPM4 CalTool calibration assistance software is used, as received data is displayed while running the calibration and is automatically recorded and reported if desired. As left data is also calculated and presented.

At any time, a) reference pressures applied; b) associated Q-RPT readings;

c)PA and PM and Poffset values, can be used to calculate as received and as left values. For example, backing out PA and PM on the as left data yields the Q-RPT

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