Environnement AF22e, Техническое руководство, Страница: 75 / 118

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AF22e
Environnement
S.A
3–41
APRIL 2016
3.5.2. ZERO AND SPAN POINT CHECK
3.5.2.1. Equipment Required
−
Zero check:
Use method described in section 3.5.1.1.
−
Span point:
Use method described in section 3.5.1.2.
3.5.2.2. Procedure
Pay attention: touching allows to display , and . Touching allows to display
and .
– Zero check:
Check that internal zero filter autonomy is higher than 30 days, or connect a zero air free of SO
2
such as a 5.0 N
2
cylinder (99.999% ultra-high purity N
2
cylinder, i.e. containing less than 10 ppm of
total impurities).
Use the key to select zero. Wait for the measurement to stabilize. The measurement should
be within ± 2 ppb (taking account the offset if it is programmed). If not, a zero calibration is
necessary.
–
Span check:
Use the key to select the span inlet port. Wait for measurement to stabilize. Result will be
compared to the concentration generated by the device used, taking account its accuracy as well
as a possible programmed offset.
3.5.2.3. Use of automatic cycles
To program the cycles, touch to access the « Automatic cycle configuration » screen (refer to section
3.4.3.2).
– Zero cycle:
The zero air filter is permanently connected to the analyzer zero air inlet port. The recommended
Zero check duration is 600 seconds, as indicated in the Duration field of the Cycles / Zero column
in the screen shown below.
–
Calibration cycle:
The span gas generation device is permanently connected to the analyzer span gas inlet port and
the span inlet is selected for span check. The SO
2
concentration must be below the full scale of the
measurement range used. The recommended check duration is 600 sec, as indicated in the
Duration field of the Cycles / Span column in screen shown below.