Instruction Manual
760000-C
November 2002
3-24 Operation Rosemount Analytical Inc. A Division of Emerson Process Management
Model NGA2000 CLD
CLD
7.50 ppm
-- Zero/span diagnostic data --
Date of last zero: Apr 28, 2001
Error message for last zero: CAL OK
Error percentage for last zero: -5
Raw signal at last zero: 0
Last zero gas would read: 0.000 ppm
Date of last span: Arp 28, 2001
Error message for last span: CAL OK
Error percentage for last span: 25
Calibration status: 789542.0
The last span would read: 10.000 ppm
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ESCAPE
INFO
FACTORS
CLD
7.50 ppm
-- Range 1 Factors --
Zero offset: 524287.0
Span factor: 0.000021250
Full scale range at calibration: 250.0 PPM
Measurement range number: 1
Raw measurement signal: 522819.7
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INFO
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HISTORY
CLD
7.50 ppm
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-- Calibration Factors --
Only those factors appropriate for the current range
Will affect the reading on the current range.
Make sure you are using the right ones!
Measurement range number: 1
Range 1 factors…
Range 2 factors…
Range 3 factors…
Range 4 factors…
ESCAPE
INFO
Figure 3-35. Zero/Span Diagnostic
Data Menu
The errors are expressed as a percentage
of the range.
The last zero and span readings are how
the analyzer would read on those gases
with the current calibration results or fac-
tors.
Calibration Factors
Calibration Factors can be used to manu-
ally set a calibration by flowing calibration
gas and setting the Factor for zero or
span until the reading conforms to the
calibration gas value. In this way, the user
can force the analyzer to any desired
reading. Alternately, the Factors can be
viewed and recorded after an automatic
calibration.
NOTE
If zero calibration is done with other
than a true zero gas followed by a span
calibration, it may be necessary to re-
peat the calibration. This is due to the
slope/intercept effect where the sub-
sequent span calibration may change
the zero crossing point.
In the “Zero/span Calibration” menu
(Figure 3-33, page 3-23), verify the
“Measurement range number:” is set to
the desired range. If not, move the cursor
to the “Measurement range number:” line
and change the setting. Press the
FACTORS (F2) softkey. The “Calibration
Factors” menu is displayed.
Figure 3-36. Calibration Factors Menu
Move the cursor to the “Range _ fac-
tors…” line corresponding to the selected
range and press
↵
. The “Range _ Fac-
tors” menu will display.
Figure 3-37. Range Factors Menu
Flow the appropriate gas (zero/span)
while adjusting the corresponding factor
(Zero offset/Span factor) until the concen-
tration reading is stabilized on the desired
calibration gas value.
The factors take effect after pressing the
↵
softkey. With zero gas, the zero factor
should be the same as the raw reading.
When the correct zero and span calibra-
tion is achieved, press the STORE (F2)
softkey to save the factors.
Use the “Measurement range number”
line to change the range and the NEXT
(F3) softkey to display the factors for the
next range.
