Thermo Scientific 42i Instruction Manual page 141

Calibration
Connect GPT Apparatus
to the Analyzer
Thermo Fisher Scientific
Note The averaging time should be less than the zero duration and less
than the span duration.
5. Verify that any filters used during normal monitoring are also used
during calibration.
6. If required, connect the analog/digital outputs to a strip chart
recorder(s) or PC(s).
The following procedure calibrates the analyzer using the gas phase titrator
and zero gas generator described previously in this manual. It is suggested
that a calibration curve have at least seven points between the zero and full
scale NO concentrations. Although the seven-point curve is optional, two
of whatever number of points is chosen should be located at the zero and
90% levels and the remaining points equally spaced between these values.
Note When the instrument is equipped with internal zero/span and sample
valves, the ZERO and SPAN ports should give identical responses to the
SAMPLE port when test gases are introduced. The user should calibrate the
instrument using the SAMPLE port to introduce the zero and span gas
sources.
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After calibration, the zero and span sources should be plumbed to the
appropriate ports on the rear panel of the instrument, and then
reintroduced to the instrument. The instrument should give identical
responses to the test gases whether they are introduced via the SAMPLE
port or the ZERO or SPAN ports. If not, the plumbing and/or valves
should be serviced.
Use the following procedure to connect the GPT apparatus to the analyzer.
1. Assemble a dynamic calibration system such as the one shown in Figure
4–1.
2. Ensure that all flow meters are calibrated under the conditions of use
against a reliable standard, such as a soap-bubble meter or wet-test
meter. All volumetric flow rates should be corrected to 25 °C and 760
mmHg.
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Calibration
Calibration
Model 42i Instruction Manual 4-9