Millipore Integritest Exacta - Calibration Adjustment Decisions; Calibration Criteria; Calibration Curve Fits; Pressure Transducer Calibration-Internal Calibration

Integritest Exacta Filter Integrity Test Instrument
Operating and Maintenance Manual Maintenance and Calibration 187
PRESSURE TRANSDUCER CALIBRATION—INTERNAL CALIBRATION
The secondary pressure transducer and regulator are compared against the primary pressure
transducer across the full operating span of the transducers (0–98 psig). The calibration is
conducted by an automated procedure that requires different operator inputs from those
required to start the calibration.
Calibration Criteria
The transducer specifications are defined in Table 19.
Table 19: Transducer Specifications
Transducer Accuracy Specification Maximum Variance
Primary Transducer +/- 0.10 psi (0.69kPa) N/A
Secondary Transducer +/- 0.33 psi (2.28kPa) +/- 0.34 (2.34kPa)
Pressure Regulator +/- 0.45 psi (3.10kPa) +/- 0.46 (3.17kPa)
Calibration curve fits:
The secondary transducer and pressure regulator have linear relationship vs. the primary
transducer. The calibration procedure compares the referee values (of the primary transducer)
against the transducer readings (of the secondary and regulator) at 6 points across the full
scale of the transducers (readings are taken at 0%, 20%, 40%, 60%, 80% and 100% of full
scale). A regression analysis is performed to determine a line of best fit and a measure of the
quality of the regression (R
2
) are calculated.
Calibration Adjustment Decisions:
• The secondary transducer and pressure regulator are matched to the primary
transducer each time an internal calibration is conducted.
• Calibration adjustment decisions are determined by R
2
in Table 20.
Table 20: Calibration Adjustment Decisions (b)
R
2
Value Decision Action
<1.82 x variance The transducers
are considered
good
No adjustments are made to the
calibration coefficients.
1.82–2.85 x
variance
The transducers
are considered
good
The secondary transducer and the
pressure regulator are matched to the
primary transducer.
>2.85 x variance The transducers
are considered
out of
specification
The unit is locked out from
performing tests. The operator should
perform an external calibration or
return it to the factory for service.