Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 485)

<Appendix E Computation Scheme>
App.E-12
IM 11B08A01-01E
When the calibration streams continues less than three times, the calibration coeffi cient is
calculated from the results obtained.
If the range of the calibration coeffi cient is set to zero, the standard area is obtained setting the
calibration coeffi cient to 1.
If the range of the calibration coeffi cient is set to other than zero, the calibration coeffi cient should
be obtained.
Note that calibration is not performed in the following conditions; they are regarded as an alarm
status:
• The calibration coeffi cient of any one of the peaks in a calibration stream exceeds the
standard range (group setting).
• The variation coeffi cient (see (g)) of any one of the peaks in a calibration stream exceeds
the requirement range (group setting).
• The concentration value of any one of the peaks in a calibration stream exceeds the
calibration range.
These calibration range are concentration ration to standard concentration.
There are set en bloc from 0 to 1.
The alarm status is removed under the following conditions.
• The results of the re-performed calibration stream does not induce an alarm status.
• The operation mode is changed.
(d) Indirect Method
The indirect method computes the concentration of the measured peak assuming that the ratio
of the area (or height) for the concentration of the standard peak to the area (or height) for the
concentration is constant.
The computation formula is:
[
c
i
= K
i
α
j
f
i
+ 1 c
j
+ B
i
a
j
f
i
A
i
( ) 2
a
j
f
i
s
i
s
j
s
i
s
j
s
i
s
j
]
Where:
c
i
: concentration of measured peak i
c
j
: measuring range of reference peak j (calibration stream) set in standard
peak j (external cublic equation processing)
s
i
: area (or height) of measured peak i
s
j
: standard area of reference peak j (calibration stream) set in standard peak j
(external cublic equation processing)
f
i
: sensitivity correction coefficient of measured peak i to standard peak j
K
i
: linearizing coefficient of measured peak i
A
i
: linearizing coefficient of measured peak i
B
i
: linearizing coefficient of measured peak i
α
j
: calibration coefficient of standard peak j
(e) Corrected Area Normalization
Corrected area normalization computes the concentration of each peak using area values
measured in a stream and taking the total area value as 1. Processing computes the
concentration by multiplying the value of each peak by the coeffi cient (the mole sensitivity
correction coeffi cient or weight sensitivity correction coeffi cient).
2nd Edition : May 11, 2012-00