8. Select - Cal. Mode Measure - Accept (To return to sample measure).
5.4 Span Calibration
A span calibration is a calibration performed at the upper end of the instrument’s measurement
range. Ecotech recommends calibration at 80% of the full scale measurement or operating range of
the instrument.
While the instrument range is commonly set as a default 0-500ppb, this is widely recognised as no
longer being valid with modern digital communication and most regulators will now recommend a
range more suited to local conditions.
Note: Ensure that the instrument has been running for at least one hour before any calibration is
performed to ensure the instrument’s stability.
The S44 instrument is essentially an NO monitor and should be calibrated as such.
During a span calibration, the instrument response to NO is adjusted and will correct the instrument
response for the NO
X
and N
X
channels.
Calibration gas can be supplied through either the Calibration Port or Sample Port. Follow the
relevant instructions below:
Note: If operating the instrument for the first time, ensure the system has been allowed sufficient
time to stabilize and for all gas lines and pathways to equilibrate and condition before performing a
calibration.
5.4.1 Conditioning the Ammonia (NH3) Sample and Calibration Lines
NH3 is a very “sticky” gas and both the measurement and calibration systems need to be properly
conditioned before commencement of any monitoring can begin.
Upon first installation, it is highly recommended that the S44 be allowed to sample NH3 calibration
gas for several hours (or overnight) to ensure the (NH3) gas line is conditioned and is free from other
contaminants which may affect your (NH3) results.
It is also highly recommended that the Ammonia (NH3) gas be delivered by a Gas Dilution calibrator
(SerinusCal) which has been isolated and dedicated to (NH3) gas/testing use only.
This will prevent the chance of contamination of other gases and therefore provide a better gas
response and converter efficiency.
Note: Ensure the calibration system provides sufficient excess flow as compared to the system draw.
5.4.2 Calibration Port
Equipment Required
Span source
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