LI-COR LI-7500, Instruction Manual

Page: 87 / 155

Section 4
Calibration 4-5
so
Z
A
A
X
A
A
Z V
co
c
co
wc
w
wo
c d
=
+
−
1
4-1
Similarly,
Z
A
A
X
A
A
Z V
wo
w
wo
cw
c
co
w d
=
+
−
1
4-2
When the span is set, the value of S
c
(or S
w
for water) is determined. For example, if there is
a known CO
2
density
ρ
'
c
in the optical path, then from Equation 2-17,
ρ ρ
α
c c ec c
c
ec
c
P f
P
S
= =

 

'