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D
SPC adjusts 1 point on the curve
leaving upper and lower limits as
set. Note the Upper limit is the
AutoCal Point.
-48.0 –46.0
Inst Reading
C
v)
Close the desiccant head when instructed to do so and press the ‘ ’ key.
vi)
The SADPminiEx will return to the Set-up Menu with the “EXIT” option
highlighted. Pressing ‘ ’ key again will return the instrument to
operational mode.
Note - Avoid carrying out the AutoCal procedure on a SADPminiEx with a full scale value of 0°C
dewpoint on days when the ambient dewpoint may to be below this value, for example a
dry day when the ambient temperature is below around 12°C.
Operation – of SADPminiEx units with full scale values of +20°C dewpoint
i)
The ambient dewpoint should be determined using reference standard, such
as a chilled mirror hygrometer or a psychrometer, unless the instrument is
being checked against a known calibration standard, from a moisture
generator.
ii)
Extend the desiccant head and press the ‘ ’ key.
iii)
The SADPminiEx will display a moving bar until it assesses that the sensor
has stabilised. (Up to 10 mins.)
vii)
The SADPminiEx will now display the full-scale value, 20°C dewpoint.
Whether the instrument is being checked against the measured ambient
level or against a known calibration standard, from a moisture generator, for
example, the scroll and
▲
and
▼
keys are used to set the value accordingly.
(If a different value has been entered in this way previously the SADPminiEx
will display that value, rather than 20°C dewpoint.) Press the ‘ ’ key when
done.
iv)
The SADPminiEx will display a moving bar whilst the calibration data is
modified. (Up to 5 mins.)
viii)
Close the desiccant head when instructed to do so and press the ‘ ’ key.
ix)
The SADPminiEx will return to the Set-up Menu with “EXIT” highlighted.
Pressing ‘ ’ key again will return the instrument to operational mode.
.
Note – 1) Pressing the scroll key during the AutoCal ABORTS the process. The AutoCal value
present at the start of the aborted AutoCal process is reinserted. The instrument is
OUT OF CALIBRATED.
2) If the Instrument fails to AutoCal (excessive sensor degradation) a message to this
effect will be displayed on the LCD screen until acknowledged by the user.
3) In both cases the instrument will be OUT OF CALIBRATION until a successful
AutoCal is performed. This will mean replacing the sensor in some cases.
4) The entered AutoCal Value must not be pressure compensated (see 11.1.2).
11.1.5
SPC (Single point Calibration)
Description – The SPC facility allows users of the SADPminiEx to check the reading of the
instrument against a “standard reference gas” or instrument, such as a chilled mirror unit, at
a particular value that may be considered to be critical, and make any adjustment necessary
to give agreement with that
“standard reference.”
Rather than making the adjustment to the
span of the instrument, as with AutoCal,
