E C O P H Y S I C S Calibration
CLD 780 TR / July 2000 88
Procedure:
1. Start diluent air (F
D
) and NO flows.
2. Adjust gas flow rate through external ozone generator (F
O
) before o-
zone generator is turned on. Wait until system is stable.
3. Execute calibration according to 6.2.2.
4. Measure NO(1) and NO.c(1) (Recommendation: use an x-t a recorder
connected to the analog output of the analyzer)
– Push ”MENU“ key, select ”Mode“ and ”NO and NO
2
“ mode. Con-
firm with ”YES“ and return with ”MEAS“.
– Push ”CAL“ key
– Select ”PLC 762“ and execute STEP 1 of GPT as described in
5.2.2.7.2 (window (42) and (43)) .
5. Switch on external ozone generator.
6. As soon as system is stable NO(2) and NO.c(2) can be measured: -
execute STEP 2 of the GPT procedure according to 5.2.2.7.2 (win-
dow (44) through (46)). The converter efficiency is calculated automa-
tically according to the formula below:
NO.c(1) - NO.c(2)
W
K
= 1 – ———————————-—
NO(1) - NO(2)
Conditions under which this formula is valid:
– NO.c(1) [ppb] must deviate less than 1 % from NO(1) [ppb]
–NO
2
impurity in NO-calibration gas <4 % of the NO concentration
Note: When determining the converter efficiency with only one CLD
780 TR, the NO
2
content of the calibration gas is unimportant, since
the NO.c channel is also always calibrated simultaneously with the
NO channel and hence the NO
2
impurity content is always measured
as well.
– NO(2) should be 10 - 50% of NO(1)
Caution: All gas flow rates must be kept constant during the whole
GPT procedure!
Caution: I
f the converter efficiency is <
50
%, the PLC 762 xenon lamp
needs to be replaced.
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