Operational Description; Installation - Tecno Control SE138PM User Manual

IST-2138.PM02.01/B
SE137PG is calibrated to detect LPG, a gas heavier than air and consists of a mixture of 20÷30% Propane
(C H ) and 80÷70% Butane (C
3 8
volume for Propane and 1.4% volume for Butane. Standard calibration to LPG is carried out for Butane gas.
SE137PI is calibrated to detect Hydrogen (H
lightest gas. Its density as to air is 0.07 and its LEL (Lower Explosive Limit) is 4% volume.
SE137PB (Unleaded Gasoline/Petrol) is calibrated to detect Gasoline vapours heavier than air and highly
flammable. Its density as to air about 2.8 and its LEL (Lower Explosive Limit) is about 1.2% volume.
SE137PX can be calibrated to detect the gases listed in
gases not listed in this table are present in the environment we suggest to use the model SE138PX-H.

OPERATIONAL DESCRIPTION

The catalytic Pellistor sensor is practically insensitive to humidity and temperature variations. The calibration is car-
ried out for the specific gas to be detected. Anyway, it can contemporaneously detect any other flammable gas that
should be present in the same environment.
Note that the LEDs are not visible when the enclosure is closed.
Preheating: when powered, the sensor needs a time of preliminary heating of about 60 seconds. During this pe-
riod the yellow LED "FAULT" flashes. After this period, the yellow LED light off, the green LED "ON" illuminates to
indicate normal functioning. After this period the unit is able to detect gas even if it attains the optimum stability
conditions after about 4 hours continual functioning.
Normal operation: the green LED "ON" should be light on.
1st ALARM: when gas concentration attains 1st alarm level the 1st red LED (ALARM 1) illuminates and after about 12
seconds, the "ALARM 1" relay will activate.
2nd ALARM: when the Gas concentration attains 2nd alarm level the 2nd red LED (ALARM 2) illuminates and after
about 30 seconds, the "ALARM 2" relay will activate.
3rd ALARM: when the Gas concentration attains 3rd alarm level the 3rd Red LED (ALARM 3) illuminates and after
about 60 seconds, the "ALARM 3" relay will activate.
Faults: the yellow LED illuminates and the "S" output falls down to 0mA. (The different faults are listed below) and
the "FAULT" normally activated relay deactivate. The "FAULT" relay, if necessary, can be used both to signal re-
motely an occurred damage and to signal the absence of power to the instrument.
Yellow LED illuminates each 4 seconds (with green LED activate): this happens when the "Cartridge Sensor" has
overcome its period of life (about 5 years) and its correct operation is not longer guaranteed. The detector keeps on
operating normally but it is necessary to replace, as soon as possible, the "Cartridge Sensor" with a new one. The type
to be required is listed on
Yellow LED activate, green LED off (FAULT relays activate and 0mA output signal): this signal different kind of
faults. 1) The Dip Switch set up is wrong, please verify
please replace with new one. 3) If a new "Cartridge Sensor" is installed or it is not correctly connected or a not com-
patible one is mounted. Please check the "Cartridge" connections and compatibility
made connecting and disconnecting the device. If the condition does not change, please replace the unit and/or
send it back to the supplier to repair.
Yellow and green LED activates (FAULT relays activate and 0mA output signal): this happens when the "Cartridge
Sensor" is not working. First try to perform the procedure of "ZERO" as described in the section "Test and Calibra-
tion > Zero adjust" then disconnect and connect the unit, finally try to replace a new "Cartridge Sensor". If the condi-
tion is not change, please replace the unit and/or send it back to the supplier to repair.
All LED activate (FAULT relays activate and >24mA output signal): this happens when the "Cartridge Sensor" is not
working or gas concentration is out of scale (higher than 100% LEL) If there are not any gas leaks and the condi-
tion is not change, please replace the unit and/or send it back to the supplier to repair.

INSTALLATION

The detector must be accurately installed and testing according to the national dispositions in force on the safety of
the plants and installation of electric devices in areas with danger of explosion.
Fig. 2
Mounting: The shows the instrument size. The unit must be positioned vertically with the sensor downwards.
Models SE138PG and SE138PB should be fixed at 20-30 cm from the floor (LPG and Petrol vapours are heavier than air).
Models SE138PM and SE138PI should be fixed at 20-30 cm from the ceiling (Methane and Hydrogen are lighter than air).
Model SE138PX should be fixed in high position with a gas Vapour Density less than 1 (the gas is lighter than air) or in bottom
position with a density greater than 1, (the gas is heavier than air)
Electrical Connection (see
Table 1. If more than one detector is to be powered in parallel, it is necessary to consider the voltage drop across
the supply cable. Normally use a two wire cable (not shielded) for power supply + the conductors for output relay. If
the output signal is used in mA, please use 3 conductors screened cables + conductors for relay output. The max load
resistor is 50 ohm with 12Vdc (-10%) power supply, while is 500 ohm with 24Vdc (-10%) power supply
Power Supply terminals, on the main board, are polarized plug-in type, it is necessary to extract them to make the
connection. The relays terminals, on outputs board, are fixed. The SSR relays are tension free SPST (Single Pole Sin-
gle Throw) contacts and should be set NO (Normally Open) or NC (Normally Closed) by positioning the 4th Dip-Switch
(see Table 3). With the Dip-Switches from 1 to 3 the concentration for alarm activations is determined.
Note: Dip-Switch should be set with instrument powered off (see Table 2). Using the unit with the Dip-
Switch in a reserved position, the fault indication will be activated (see "Operational description> Faults").
TECNOCONTROL S.r.l. Via Miglioli 47 SEGRATE ( MI )
Istruzione / User's Manual / Manuel d'utilisation
H ). Propane density as to air is 1.56 while Butane' is 2.05. The LEL is 1.7%
4 10
Page 1. The replacement procedure is described in the attached manual.
Fig.2): the maximum distance to install each detector from the power supply show in the
), is a colourless, odourless, highly flammable gas and is the
2
Table 4, it is used in low polluted environments. If other
(see Table 2 and 3). 2) The "Cartridge Sensor" is not working,
(see Table 4 – column
(see on page 1) these checks are
n.4).
(see
Tel: 02/26 92 28 90 Fax: 02/21 33 734
Pag.5/11
fig.4).