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IST-2192.KM02.01/B
Aprire il coperchio della custodia. Per eseguire la verifica o la taratura possono essere utilizzati due metodi.
Il primo permette di leggere direttamente il valore in mA, ed è necessario collegare in serie al morsetto "S" un mul-
timetro (scala 20 mA) (Fig. 2). Tenere presente che quando si stacca il filo la centralina va in "guasto".
Il secondo, permette, senza staccare il filo "S", di misurare i mV corrispondenti al segnale 4÷20mA
con un multimetro (Scala 200mV) posizionare i puntali sui punti TP1(+) e TP2(-) (TEST). Per trasformare il valore
da mA a mV è sufficiente moltiplicare il valore in mA x 10.
"Regolazione dello ZERO" in aria pulita il valore letto deve essere di 4mA (±0,1) oppure 40mV se misurati su
TEST (TP1 e TP2). Nel caso in cui non si riscontrasse tale valore regolare lentamente il trimmer P2 fino ad ottene-
re il valore richiesto.
"Regolazione del FONDO SCALA" se si dispone della bombola con la stessa
miscela Gas/aria per cui è stato tarato il trasmettitore, collegare la bombola al
portagomma del Flussometro (Fig. 2), far affluire il gas a circa 0,15÷0,3 l/min,
attendere circa 2 minuti e verificare che il valore letto sul multimetro sia:
Esempio: Se si deve verificare un sensore Mod.SE192KG tarato con Butano
se il certificato della bombola indica 0,29%v/v (=19,5%LIE) Butano e il fondo
scala del trasmettitore in %LIE è 0,3%v/v, l'uscita deve essere 19,46 (Tolleran-
za ±0,5mA). Nel caso in cui non si riscontrasse tale valore ruotare il trimmer P1
SPAN posto sul circuito stampato fino a leggere il valore richiesto.
EN
GENERAL INFORMATION
The models series SE192K, is a three-wire 4÷20mA linear transmitters able to detect combustible gases employing
a catalytic sensor calibrated up to 20% LEL to Methane or LPG.
The instrument comprises of a thermoplastic terminal box which contains the electronic circuit, the connecting ter-
minals and the sensor placed in its housing on the cover.
The SE192K are normally connected to the TECNOCONTROL gas detecting central systems for heating plants, as
shown in the Table on
page
OPERATIONAL DESCRIPTION
The catalytic sensor is practically insensitive to humidity and temperature variations. The sensor being designed to
detect flammable gases and the calibration is carried out with the specific gas to be detected. Anyway, it can con-
temporaneously detect any other flammable gas that should be present in the same environment.
Preheating: when powered, the SE192K starts a time of preliminary heating of about 30 seconds. During this pe-
riod the output is 0mA. After this period, the sensor is able to detect gas even if it attains the optimum stability con-
ditions after about 48 hours continual functioning.
Therefore, after that time we advise to check in clean air the "4mA" output. If is necessary "4mA calibration" can be
carried out as explained on page 4. This calibration is necessary to adjust the sensor to the environment condi-
tions.
Faults: In case of sensor damage, the "S" output falls down to 0mA (FAULT). The signal is then indicated as a
damage situation.
All this happens also when an interruption to the connection wires between the sensor and the detector occur.
Average life: The sensitive element used in this detector has an excellent stability in time. In fresh air and in nor-
mal working condition the sensor's life is about 5 years from the date of installation.
Periodical testing: we advise to carry out working tests every 6-12 months. After 2 year, we advise to proceed to
the recalibration of the circuit with Gas/Air mixture as explained on
Attention
: please note that in polluted environments, where vapours of flammable agents, especially
solvents, might be present, the periodical testing and recalibrations should be carried out at shorter time
intervals. In polluted environments, the sensor's life can be reduced.
INSTALLATION
The detector must be accurately installed according to all the national dispositions in force on the safety of the
plants and installation of electric devices in areas with danger of explosion.
Positioning: the SE192K must be installed as shown in
Models SE192KG should be fixed at 20-30 cm from the floor (LPG and Petrol vapours are heavier than air).
Models SE192KM should be fixed at 20-30 cm from the ceiling (Methane and Hydrogen are lighter than air).
Electric connections
: are to be carried out using the three-pole terminal (See special instructions enclosed with
the gas detectors). It is not necessary to use shielded cables.
The transmitters can be placed at a max. distance of 100 meters from the gas detector when 3x1.5mm
used, and 200 meters with 3x2.5 mm
WARNING
Calibration is carried out with gas. Absolutely trimmer P3 must not be tampered with. The calibration routine is to
be carried out by trained or authorised personnel only. As an alternative, it is advised to check the calibration with-
out operating on the trimmers, and in case the values are not the required ones please apply to our Laboratory.
TECNOCONTROL S.r.l. Via Miglioli 47 SEGRATE ( MI )
Istruzione / User's Manual / Manuel d'utilisation
6.
2
cables.
page 4.
fig.3 on page
6.
Tel: 02/26 92 28 90 Fax: 02/21 33 734
Pag. 3 / 6
. In questo caso,
16
x
%v/v
Gas
Bombola
mA
=
Fondo
Scala
Sensore
in
mV =
mA x
10
16
x
0,29
mA
4
=
19,46
=
+
0,3
mV
19,46
x
10
194,6
(195)
=
=
2
cables are
4
+
%v/v
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