Series 4 Operating Manual - Nebula
Issue 1.00
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6.3
Control
Once the analyser is powered on it may be controlled using either the wireless tables or
optional S4i for computer use. (See the appropriate User Guides provided for further
information).
6.3-1
Calibration
Calibration Requirements
The TDLS detector within the analyser will reliably measure a sample gas with 5% or more
H
2
O present. Therefore, for accurate calibration, anhydrous NH
3
of a known PPM value is
required to be mixed with humidified air/zero gas. The diagram below is the recommended
experimental setup for doing this:
Figure 3: Nebula Calibration Schematic
Signal Group LTD provide an external calibration unit with humidifying capabilities that will aid
this process. Please contact the Sales team if this is something you require.
Zero/Span Calibration
‒
The procedures for calibration of the zero offset and span coefficient are fully automated.
The process is as follows:
‒
Enter the span gas bottle concentration values as described in your chosen interface
guide
‒
Select Calibrate while the unit is lit and stable to initiate the process. The analyser will
start by choosing the correct gas path (if not already selected), to allow the calibration
gas to flow.
‒
It will then monitor the measurements to determine the point at which they have become
stable enough to use as a reference for calibration.
