PN 305200901, Rev YT
Span Factor
Span Factor, ID Number 6E Hex, is simply a multiplication factor to the mois-
ture (PPMV) readings. This factor is manipulated by the software every time
you run a Verication/Calibration. For example, by increasing this factor to
1.10, the analyzer readings will be 10 % higher. Conversely, by decreasing this
factor to 0.9 the analyzer readings will be 10 % lower. AMETEK analyzers leave
the factory with Moisture Span set to 1.00. Normal Span Factor numbers in the
eld will range from 0.5 to 3.00.
There are limits in the software to this parameter (ID Numbers 94 and 95 Hex).
ID Number 94 is the high limit (3.00) and 95 is the low limit (0.3). These limits
are adjustable. Any analyzer with a Span Factor reaching 3.00 requires detector
(cell) replacement. Faulty Dryers might also have an impact on this number.
As contamination from a gas stream gets deposited on the detector, this will
cause its sensitivity to decline.
To compensate for this, run a Verication/Calibration, which will make the
necessary Moisture Span adjustments. This is equivalent to restoring the sen-
sor (cell) sensitivity. This Span Factor may be interpreted as “electronic gain.” A
gain of ‘1’ is perfect (neutral). As the gain approaches a value of ‘2’, the amount
of gain is doubled.
Maintenance and Troubleshooting | 4-21
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