E Instruments 4400, Manual

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5.3 Gas sensor life
The gas sensors used in this instrument are electrochemical: thus, when the relative gas is detected, a chemical
reaction takes place inside them that generates an electrical current.
The electrical current acquired by the instrument is then converted into the corresponding gas concentration.
Sensor life is strongly related to the consumption of the reagents within.
Sensor characteristics diminish as the reagents are consumed and when these have been used up completely
the sensor must be replaced. The sensors must be recalibrated on a regular basis to assure measuring
accuracy: recalibration can only be performed by a qualified E Instruments service center. Chart 5.4 illustrates
the characteristics inherent to each sensor.
5.4 Gas sensors life
Notes:
(1) Coloured dot on the sensor electronic board.
(2) UNI 10389-1 standard requires for the instrument calibration once per year to be performed in a laboratory
authorized to issue calibration certificates.
CODE MEASURED GAS
IDENTIFYING
COLOR
AVERAGE LIFE RECALIBRATION
FLEX-Sensor O
2
Cod. AAA32-240
O
2
Oxygen
Yellow 18 months not necessary
FLEX-Sensor CO+H
2
Cod. AACSE05
CO
Carbon M onoxi de
Red 48 months Yearly
(2)
FLEX-Sensor NO
Cod. AACSE06
NO
Nitrogen O xide
Orange 48 months Yearly
(2)
FLEX-Sensor NO
2
Cod. AG526-W00
NO
2
Nitrogen Dioxi de
White 36 months Yearly
(2)
FLEX-Sensor SO
2
Cod. AD527-W04
SO
2
Sulphur Dioxide
Green 36 months Yearly
(2)
FLEX-Sensor CO
100.000
CO
Carbon M onoxi de
Purple 48 months Yearly
(2)
FLEX-Sensor CO 20.000
CO
Carbon M onoxi de
Blue 48 months Yearly
(2)
FLEX-Sensor CO+H
2
low range
Cod. AACSE24
CO
Carbon M onoxi de
Red 48 months Yearly
(2)
FLEX-Sensor NO
low range
Cod. AACSE25
NO
Nitrogen O xide
Orange 48 months Yearly
(2)
FLEX-Sensor NO
2
low range
Cod. AACSE26
NO
2
Nitrogen Dioxi de
White 48 months Yearly
(2)
FLEX-Sensor SO
2
low range
Cod. AACSE28
SO
2
Sulphur Dioxide
Green 48 months Yearly
(2)
( 1 )
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