55
2) In case of sample switching system
(1) After warming up the instrument, supply
dry nitrogen at a rate of 1
r
/minute from
the measured gas inlet.
Detach the pipe from the reference cell gas
inlet (light source side) and flow dry
nitrogen at 1
r
/minute.
(2) Carry out zero calibration using the ZERO
and CAL keys.
(3) Set up the interference compensation
setting mode as in section 6-4. “
” will
appear in the upper two digits of the main
indicator on the front panel while a total of
5 numerals will appear in the lower digit of
the main indicator plus the four digits of
the sub indicator.
(A negative sign appears in the second
lowest digit of the main indicator.)
(4) Supply interference gas (0
°
C or 2
°
C
saturated H
2
O) as shown in the figure.
When the indication has stabilized, adjust
by using the
and
keys so that the
indicated value approaches zero or within
2% of the value obtained by driving 30,000
by the range ratio.
When range ratio is 1 : 5 (low range :
high range)
1
30,000
×
×
0.02 = 120
5
Adjust to obtain a value of nearly zero
within
±
120.
(5) Return the reference cell pipe to its original
position.
Dry nitrogen 1
r
/min.
∧
＞
NO
CAL
NO
NO
N
2
Water
Bubbler
Cold water or
electronic cooler
Measured gas
inlet:
0 or 2
℃
saturated H
2
O
