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10.2.
PREDICTING FAILURES USING THE TEST FUNCTIONS
The Test Functions can be used to predict failures by looking at how their values change
over time. Initially it may be useful to compare the state of these Test Functions to the
values recorded on the printed record of the final calibration performed on your
instrument at the factory, P/N 04307. Table 10-3 can be used as a basis for taking action
as these values change with time. The internal data acquisition system (DAS) is a
convenient way to record and track these changes. Use APICOM to download and
review this data from a remote location.
Table 10-3: Predictive uses for Test Functions
FUNCTION
CONDITION
BEHAVIOR
INTERPRETATION
STABILITY
Zero Cal
Increasing
•
Pneumatic Leaks – instrument & sample system
•
Detector deteriorating
CO MEAS
Zero Cal
Decreasing
•
Source Aging
•
Detector deteriorating
•
Optics getting dirty or contaminated
MR RATIO
Zero Cal
Increasing
•
Source Aging
•
Detector deteriorating
•
Contaminated zero gas (H
2
O)
Decreasing
•
Source Aging
•
Detector deteriorating
•
GFC Wheel Leaking
•
Pneumatic Leaks
•
Contaminated zero gas (CO)
Span Cal
Increasing
•
Source Aging
•
Pneumatic Leaks – instrument & sample system
•
Calibration system deteriorating
•
GFC Wheel Leaking
Decreasing
•
Source Aging
•
Calibration system deteriorating
PRES
Sample
Increasing > 1”
•
Pneumatic Leak between sample inlet and Sample Cell
•
Change in sampling manifold
Decreasing > 1”
•
Dirty particulate filter
•
Pneumatic obstruction between sample inlet and
Sample Cell
•
Obstruction in sampling manifold
PHT DRIVE
Any, but with
Bench Temp at
48°C
Increasing
•
Mechanical Connection between IR-Detector and
Sample Cell deteriorating
•
IR-Photodetector deteriorating
OFFSET
Zero Cal
Increasing
•
See MR Ratio - Zero Cal Decreasing above
Decreasing
•
See MR Ratio - Zero Cal Increasing above
SLOPE
Span Cal
Increasing
•
See MR Ratio - Span Cal Decreasing above
Decreasing
•
See MR Ratio – Span Cal Increasing above
06864D DCN7562
Summary of Contents for T300
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