Figure 4-1. Calibration Flow Schematic; Zero Adjust - Thermo Scientific 48i Instruction Manual

Calibration
Calibration

Zero Adjust

4-4 Model 48i Instruction Manual
Figure 4–1. Calibration Flow Schematic
Use the following procedure to set the CO reading to zero.
1. Allow sufficient time for the Model 48i to warm up and stabilize.
2. Adjust the dilution system of
present in the manifold.
Since not all flow controllers have a positive shut off, it might be
necessary to disconnect the CO input line and cap it.
3. Allow the instrument to sample zero air until a stable reading is
obtained.
4. Press and choose Calibration > Cal Background.
5. In the Cal Background screen, press
zero.
If a strip chart recorder is used to obtain a record of the analog output, it is
recommended that the system be adjusted to obtain a zero trace at 5% of
scale. This is to allow observation of zero drift and/or zero noise. Record
the stable zero air response as Z.
Figure 4–1 so that zero air alone is
to set the CO reading to
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