Instruction Manual
760000-C
November 2002
Rosemount Analytical Inc. A Division of Emerson Process Management Operation 3-21
Model NGA2000 CLD
CLD
7.50 ppm
HOME
-- Calibration Gas List --
Zero gas – range 1: 0.00 ppm
NO span gas – range 1: 10.00 ppm
NOx span gas – range 1: 10.00 ppm
Zero gas – range 2: 0.00 ppm
NO span gas – range 2: 10.00 ppm
NOx span gas – range 2: 10.00 ppm
Calibration…
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3-8 CALIBRATION PROCEDURE
The CLD analyzer module may require peri-
odic calibration with known zero and span
gases in order to maintain a desire level of
analytical accuracy. It is recommended, after
initial startup, that the CLD Analyzer Module is
calibrated at least once every eight hours.
This practice should continue until evidence
indicates that some other interval is more ap-
propriate depending on the analytical accu-
racy required.
Calibration is the process of flowing known
zero or span calibration gas into the analyzer
for a specified period (averaging time), after
which the analyzer will automatically set its
zero or span factors so that the concentration
measurement equals the calibration gas
value. A limit can be set, beyond which any
attempt by the analyzer to reset its concentra-
tion measurement will cause a warning alarm.
In this case, user intervention would be re-
quired to reset the alarm and attempt another
calibration.
There are three methods for performing a
calibration with the CLD Analyzer Module and
NGA Platform:
Basic Controls calibration
:
(See Section 3-
8b, page 3-22)
This method allows the user to input a span
calibration gas value and perform a zero or
span calibration for each of the four ranges.
This method uses calibration parameters es-
tablished in the module setup menus. (See
Section 3-8a, page 3-21)
Expert Controls calibration
: (See Section
3-8c, page 3-23)
This method allows the user to perform a zero
or span calibration for each of the four ranges,
enable or disable the calibration adjustment
limits, view the results, and view or change
the Factors that the analyzer uses to adjust
the zero and span concentration reading. This
method uses calibration parameters estab-
lished in the module setup menus. (See Sec-
tion 3-8a, page 3-21)
System calibration and setup
:
This method allows the user to establish com-
plex automated calibration sequences for
modules bound to the Platform. This is fully
described in the Platform manual.
NOTE
If zero calibration is done with other than a
true zero gas followed by a span calibra-
tion, it may be necessary to repeat the
calibration. This is due to the
slope/intercept effect where the subse-
quent span calibration may change the
zero crossing point.
a. Calibration
Setup
Calibration Gas List
This menu is used to set the concentra-
tion values of the calibration gases for
each range. These values are used for all
calibrations except in Basic where the
span gas can be entered for a quick man-
ual calibration.
Main Menu
↓
Analyzer and I/O expert controls &
setup…
↓
Analyzer module setup…
↓
Calibration gas list…
Figure 3-31. Calibration Gas List Menu
Use the MORE (F3) softkey to display
and change the values for the remaining
ranges.
