Yokogawa GC8000 Process Gas Chromatograph - Manual (Page 484)

<Appendix E Computation Scheme>
App.E-11
IM 11B08A01-01E
• When the range of the calibration coeffi cient is zero:
Standard area = (Integrated area value / The number of integration) * (Measuring range /
Standard concentration)
Calibration coeffi cient = 1
• When the range of the calibration coeffi cient is other than zero:
Calibration
coeffi cient = ((Integrated are value / The number of integration) * (Measuring
range / Standard concentration)) / Standard area
(2) During measurement
Calculate the concentration of peak i using standard concentrations and areas (or heights)
of reference peaks j and k.
The area of reference peak j, S
j
, is calculated as follows.
S
j
-= a
j
SO
j
(CO
j
/ R
j
)
Where:
S
j
: area of reference peak j
a
j
: calibration coeffi cient
SO
j
: standard area
CO
j
: standard concentration
R
j
: measuring range
The area of reference peak k, S
k
, is calculated as follows.
S
k
= a
k
SO
k
(CO
k
/ R
k
)
Where:
S
k
: area of reference peak k
a
k
: calibration coeffi cient
SO
k
: standard area
CO
k
: standard concentration
R
k
: measuring range
Coeffi cients a and b in the linear equation are calculated as follows.
a =
b = C
j
– aS
j
C
j
– C
k
S
j
– S
k
The concentration of peak i is calculated as follows.
c
i
= as
i
+ b
Where:
c
i
: concentration of peak i
s
i
: area (or height) of peak i
a : slope of the linear equation (coefficient)
b : intercept of the linear equation (coefficient)
C
j
: concentration of reference peak j
C
k
: concentration of reference peak k
(c) Calibration Computation
The calibration stream, validation stream, and measurement stream are set for each stream. As
for the calibration stream, the standard area or calibration coeffi cient is obtained for each peak.
When the calibration streams continues three times or more the calibration coeffi cient is obtained
using the average of the last three results.
2nd Edition : May 11, 2012-00
App.E