RPM4-AD™ OPERATION AND MAINTENANCE MANUAL
© 2005-2007 DH Instruments, a Fluke Company
Page 116
The calibration process is performed independently on each Q-RPT to arrive at its optimal fit. As
RPM4-AD 160K/A160K has two identical Q-RPTs, the calibration sequence may be run on both
of them simultaneously but they are adjusted independently.
CalTool for RPTs software provided with the RPM4-AD supports the calibration process
of RPM4-AD Q-RPTs. CalTool and its documentation are provided on a General Accessories Disk
with a new RPM4-AD and can be downloaded from www.dhinstruments.com. Most users
should use CalTool software to assist in the calibration of RPM4-AD.
RPM4-AD 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 RPM4 General Accessories Disk). RPM4-AD 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).
5.2.1.1
PA 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 RPM4-AD
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 changes the 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-AD is delivered with PA and PM values set to zero for both
Q-RPTs. This does not mean that the RPM4-AD 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.
5.2.1.2
AS RECEIVED AND AS LEFT DATA
Frequently, calibration procedures require reporting as received and as left data.
The necessary information to report as received and as left data on the
calibration of RPM4-AD Q-RPTs can be obtained in several ways.
When the RPM4-AD 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.
