Notes On The Detected Gas; Operational Description - Tecno Control SE137EC-S Manuel D'utilisation

IST-2137.EC03.01/B
2nd Red LED "ALARM 2":
1st Red LED "ALARM 1":
Green LED "ON":
Yellow LED "FAULT":
The instrument has a 4÷20mA linear output (S) with 300 ppm CO F.S. This output is connectable to a remote
Central Unit and/or used for the Test and Calibration routine.

NOTES ON THE DETECTED GAS

The above Gas value is on compliance with EN61779-1.
Carbon monoxide (CO) is a colourless, odourless, tasteless, poisonous gas produced by incomplete burning of
carbon-based fuels, including gas, oil, wood and coal. Carbon-based fuels are safe to use. It is only when the fuel
does not burn properly that excess CO is produced, which is poisonous. When CO enters the body, it prevents the
blood from bringing oxygen to cells, tissues, and organs.

OPERATIONAL DESCRIPTION

The electrochemical sensor is temperature compensated, but is sensitive to extreme humidity variations. The cali-
bration is carried out with CO gas. Anyway, it can contemporaneously detect other gases that should be present in
the same environment as listed in
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.
ALARMS: different alarms levels can be set by Dip-Switch
normal one, will activate the corresponding relays after a fixed delay, the advanced one, operate with TLV-TWA,
STEL and C value, in this case the relays will activate without delay.
The 1st° Red LED (ALARM 1) illuminates when the Gas concentration attains 1st alarm level. Under normal alarm
method, after about 12 seconds the "ALARM 1" relay will activate, while under advanced one, with TLV-TWA level
selected, the relay will activate without delay.
The 2nd Red LED (ALARM 2) illuminates when the Gas concentration attains 2nd alarm level and after about 30
seconds, the "ALARM 2" relay will activate or without delay when TLV-STEL level is selected.
The 3rd Red LED (ALARM 3) illuminates when the Gas concentration attains 3rd alarm level and after about 60
seconds, the "ALARM 3" relay will activate or without delay when TLV-C level is selected.
TLV (Threshold Limit Values) are defined as an exposure limit to which it is believed nearly all workers can be exposed
day after day for a working lifetime without ill effect.
TLV-TWA (Threshold Limit Value – Time-Weighted Average) is the time-weighted average concentration for a conventional
8-hour workday and a 40-hour workweek, to which it is believed that nearly all workers may be repeatedly ex-
posed, day after day, without adverse effect.
TLV-STEL (Threshold Limit Value – Short-Term Exposure Limit) is the concentration to which it is believed that workers can
be exposed continuously for a short period of time without suffering from irritation, chronic or irreversible tissue
damage, or narcosis. STEL is defined as a 15-minute TWA exposure, which should not be exceeded at any time
during a workday.
TLV-C (Threshold Limit Value - Ceiling) is the concentration that should not be exceeded during any part of the working
exposure.
The values are recommending exposure levels that are protective to workers, OSHA (Occupational Safety and Health
Administration, of the U.S. Department of Labour) and COSHH (Control Of Substances Hazardous to Health in Europe).
Faults: the instrument signal different kind of failures, as listed below. The Yellow LED illuminates, the "S" output
falls down to 0mA and the "FAULT" normally activated relay deactivate. The "FAULT" relay, if necessary, can be u-
sed both to signal remotely 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 theoretical period of life and its correct operation is not longer guaranteed. The detector keeps on op-
erating normally but it is necessary to replace, as soon as possible, the "Cartridge Sensor" with a new one. The
type to be required is described at Page1. The replacement procedure is described in the attached manual.
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
se 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, it will be necessary to 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
condition is not change, it will be necessary to 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 375ppm) If there are not any gas leaks and the condition
is not change, it will be necessary to replace the unit and/or send it back to the supplier to repair.
TECNOCONTROL S.r.l. Via Miglioli 47 SEGRATE ( MI )
Istruzione / User's Manual / Manuel d'utilisation
2nd relay activation
1st relay activation
normal working condition
the sensor should be faulty, disconnected, out of scale or expired.
table 4.
(see Table
(see table 3). There are two different alarm methods, the
2). 2) The "Cartridge Sensor" is not working, plea-
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Pag.5/11
(see Table 3) these checks are