LumaSense Technologies INNOVA 1412i - Manual (Page 193)

Chapter 14
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BE6025-15 1412i Photoacoustic Gas Monitor LumaSense Technologies A/S
Page 193 of 202
relationship between the gas signal in the cell and the concentration of
the gas (in which case only a single-point span calibration is required).
SPAN CALIBRATION IMPOSSIBLE
This message is associated with the span calibration of the water-
vapour filter.
The above message indicates that the Monitor cannot calculate the
gas conversion factor. This could indicate that the concentration of
water-vapour used during the calibration was too low – this could
either be due to an incorrectly “entered” water-vapour concentration
in the set-up of the span calibration or that the concentration of
water-vapour used was not the same as that which was “entered” in
the set-up.
14.4.2 “Successful*” Error Messages
WATER VAP. MEAS. < OFFSET MEAS
This message is associated with one, or more, of the following
calibration tasks: (1) the one- or two-point span calibration of an
optical filter; (2) the cross-interference calibration of the installed
optical filters ("A” to “E”); (3) the zero-point calibration of all the
installed optical filters (“A” to “E”).
During all the above-listed calibration tasks, the signal in the cell is
measured using the water-vapour filter: this enables the Monitor to
compensate for any interference signal produced by the presence of
any water-vapour in the span gas being used. If the signal in the cell
using the water-vapour filter is found to be less than the concen-
tration offset factor for the water-vapour filter, the above message
is sent.
This could indicate that the zero gas you used, during the zero-point
calibration of the water-vapour filter, was not perfectly dry.
SPAN MEASUREMENT TOO LOW
This message is associated with the span calibration of one (or more)
of the filters.
The above message indicates that the signal measured in the cell
during span calibration is less than 3µV and therefore cannot be used
to obtain a good calibration. This means that the concentration of your
span gas is too low.