DH Instruments PPC4, Руководство по эксплуатации и обслуживанию

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PPC4™ OPERATION AND MAINTENANCE MANUAL
© 2009 DH Instruments, a Fluke Company Page 184
When running calibrations, collecting as received data and calculating PA and PM
adjustments, whether AutoZ is normally used, whether it is ON or OFF and what the value of
Zoffset is should be considered (Section 3.2.22).
Note
CalTool for RPTs software provided with the PPC4 supports the calibration
process of PPC4 Q-RPTs. CalTool and its documentation are provided on a
General Accessories Disk with the new PPC4. Most users should use
CalTool software to assist in the calibration of PPC4.
PPC4 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). PPC4 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 7.2.8).
Note
PPC4 may also use external Q-RPTs mounted in RPM4 Reference Pressure
Monitors. RPM4 Q-RPTs are calibrated independently of PPC4 (see the
RPM4 Operation and Maintenance Manual).
7.2.1.1 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 in the CAL function (see Section 6.5.4).
PA and PM values are automatically edited when CalTool software is used and
the results are activated.

Caution
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 3.2.26.5). Incorrect editing of PA and PM
values can cause out of tolerance measurements.
Note
A new PPC4 is delivered with PA and PM values set to zero and
1 for all Q-RPTs. This does not mean that the PPC4 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.