Rosemount Analytical NGA 2000, Руководство пользователя

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S
TARTUP AND
O
PERATION
3-8
June 1997 Rosemount Analytical 748332-D NGA 2000 Non-Dispersive Infrared Analyzer
3.6 LINEARIZATION
The NDIR Analyzer Module can be operated in linear and non-linear mode.
Linearization can be toggled ON/OFF in
the Expert Controls menu (see Figure 3-10).
In the OFF position, linearization is disabled for all ranges, and the component of
interest is measured in percent of fullscale. In the ON position, measurement is in
engineering units: Either ppm or percent of concentration.
The NDIR Analyzer Module is linearized with the following fourth-order polynomial:
Y = A
O
+ A
1
X + A
2
X
2
+ A
3
X
3
+ A
4
X
4
Where:
X = the normalized non-linear input
A
O
, A
1
, A
2
, A
3
, A
4
= linearization coefficients
Y = the normalized linear output
Linearization coefficients can be developed and stored for each range through the
Expert Controls menu. The operating range is selected by entering RANGE = 1, 2, 3
or 4 in the Range Mode section that that menu.
Coefficients for each selected range are automatically used when the module is in
Linearization Mode. The user instructs the Analyzer Module as to which set of
coefficients are to be used for each range. Maximum dynamic range is 3:1.
When ordered, special linearization coefficients for non-standard fullscale ranges are
entered in the appropriate range(s) at the factory. If a range is not specified, the set of
coefficients will be for Range 4.
The operator may want the module to output measurement in engineering units (ppm).
This response is linear over the operating range. The following coefficients will make
no correction to the non-linear response, but will cause the NDIR Analyzer Module to
output gas measurement in engineering units:
A0 = 0.00000
A1 = 1.00000
A2 = 0.00000
A3 = 0.00000
A4 = 0.00000
To calculate linearization coefficients other than those installed at the factory, take a