Unitec ETL3000 Operation manual

ORION S.r.l.
Via A. Volta, 25/b - 35030 Veggiano (PD) – Italy
Tel: [phone] - Fax: [phone]
Web: www.unitec-srl.com – Email: [e-mail]
Web: www.orion-srl.it - Email: [e-mail]
UniTec is a brand of
ETL3000/ETLONE
MULTI-COMPONENT
AIR QUALITY MONITOR
Operation and Service Manual
Ver. 02/17

We have checked the contents of this manual for agreement
with the hardware and software described. Since deviations
cannot be excluded entirely, we cannot guarantee full
agreement. However, the data in this manual are reviewed
regularly and any necessary corrections are included in
subsequent editions. Suggestions for improvement are
welcomed.
Technical data subject to change.
The production, transmission or use of this document or its
contents is not permitted without express written authority.
Offenders will be liable for damages. All rights, including
rights created by patent grant or registration of a utility model
or design, are reserved.
Copyright ORION Srl 2017. All Rights Reserved
Printed in Italy
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 2/35

CONTENTS
1INFORMATION FOR THE USER ..........................................................................................6
1.1 General information 6
1.2 Notes on Using this Manual 7
1.3 Danger information 7
1.4 Approved Use 8
1.5 Qualified Personnel 8
1.6 Warranty information 9
1.7 Supply and Delivery 9
1.8 Standards and Regulations 9
1.9 Declaration of Conformity 10
2INSTALLATION GUIDELINES ............................................................................................11
2.1 Safety Information 11
2.2 General 11
2.3 Electric Connection 12
2.4 Connection of input signals 12
2.5 Installation 13
2.5.1 Fixed installation 13
3TECHNICAL DESCRIPTION ...............................................................................................14
3.1 ETL: TECHNICAL DATA 14
3.1.1 Optional accessories – Technical data 15
OPTIONS FOR ETL UNIT........................................................................................................15
3.2 Applications 16
3.3 Measuring principle of SENS-IT sensors 17
3.4 Technical Specifications of sensors 20
3.5 Technical Specifications of optional sensors 20
3.6 Specification of optional MET3000 Meteorological station 21
4START-UP OF ETL3000 /ETLONE......................................................................................22
4.1 Precautions to be followed for a correct installation and for a valid data acquisition 23
5TEST AND CALIBRATION.................................................................................................24
5.1 Test control 24
5.2 Yearly calibration 24
5.3 Calibrating the Temperature and Relative humidity sensor -METBASIC Kit 25
5.4 Calibrating the noise sensor 25
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 3/2

6BUILT-IN DATA LOGGER..................................................................................................27
6.1 Communication commands 28
6.1.1 Command to memorize the calibration curves 29
6.1.2 Command to set date and time 31
6.1.3 Command for average data transmission 31
6.1.4 Buffer Reset 32
6.1.5 System Restart 32
6.1.6 Download Meteo data 32
6.2 Remote Data Transmission 32
7SOFTWARE @COM-3000 ................................................................................................33
8RETURNED DELIVERIES ...................................................................................................36
8.1 Damaged Shipment 36
8.2 Shipping discrepancies 36
9SERVICE AND SPARE PARTS ............................................................................................37
9.1 Spare parts list 37
10 ANNEX I......................................................................................................................39
10.1 ETL3000 mini guide communication protocol 39
10.2 Annex II – SENS3000 AND SENS-IT CALIBRATION PROCEDURES 41
11 WASTE EQUIPMENT .......................................................................................................44
12 FREQUENT ASKED QUESTIONS ........................................................................................45
12.1 Electronics 45
12.1.1 Display with light but no characters 45
12.1.2 The date on the display is not correct. 47
12.1.3 Lo strumento non risponde sulla porta seriale. 47
12.1.4 Lo strumento è rimasto spento per mesi. 47
12.1.5 Lo strumento non si accende. 47
12.1.6 Il display rimane spento. 48
12.2 Sensori 48
12.2.1 Sul display le concentrazione dei gas riportano valori con molte cifre. 48
12.2.2 I valori a display dei gas sono o a zero o a fondo scala. 49
12.2.3 Il led della camerina SENS-IT è spento. 49
12.3 Polveri. 49
12.3.1 PDR1500. I valori delle polveri sono sempre zero. 49
12.3.2 PDR1500. I valori delle polveri sul display del modulo polveri sono a fondo scala. 49
12.3.3 Osiris. Sul display dell’ETL viene visualizzato NACQ come valore delle polveri. 50
12.3.4 Osiris. I valori delle polveri sono molto alti. 50
12.4 Meteo. 51
12.4.1 Sul display dell’ETL compare NC o NV in corrispondenza dei parametri meteo MET3000. 51
12.4.2 I valori sul display dell’ETLdei sensori meteo MET3000 sono a fondo scala. 52
12.5 Trasmissione dati. 52
12.5.1 Dopo lo scarico dei dati con @COM3000 si ottiene il messaggio “Buffer Empty”. 52
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 4/2

12.5.2 Non si riceve risposta dal modem. 52
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 5/2

Information for the user
1Information for the user
Dear Customer,
Please read this manual before you start to work!
It contains important information and data whose observance will guarantee correct functioning of
the instrument and also save you servicing costs. The information will significantly help you when
using the equipment and will lead to reliable results.
1.1 General information
The product described in this Manual has left the factory in a perfect and tested condition as
regards safety. In order to retain this state and to achieve correct and safe operation of this product,
it must only be used in the manner described by the manufacturer. In addition, correct and safe
operation of this product is dependent on proper transport, storage and installation as well as
careful operation and maintenance.
This Manual contains the information required for approved use of the product described in it. The
Manual has been prepared for technically qualified personnel who have been specially trained or
who possess appropriate knowledge in the field of instrumentation and control, referred to further
as automation technology.
Knowledge of the safety information and warnings present in this Manual and their technically
correct implementation are prerequisites for danger-free installation and commissioning and for
safety during operation and maintenance of the described product. Only a qualified person
possesses the required specialist knowledge to correctly interpret the general safety information
and warnings present in this Manual and to apply them to the specific case.
This Manual is included in the delivery of the ETL series unit, even if separate ordering has been
made possible for logistic reasons. For clarity reasons this manual cannot describe every possible
case in connection with installation, operation, maintenance or the use in systems.
Should you require further information, or should particular problems occur which are not handled
in sufficient depth in this manual, help can be requested through your local ORION representative
or contacting the UniTec Service Department at ORION Srl, Veggiano (PD) – Italy at
[e-mail]
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 6/35

Information for the user
1.2 Notes on Using this Manual
This Manual describes the applications of the equipment and how you can start it up, operate
and service it.
Of particular importance are the warning and information texts.
These are separated from the remaining text, specially identified by appropriate pictograms
(see Section 1.3).
1.3 Danger information
Safety information and warnings serve to prevent danger to the life and health of users or
maintenance personnel or to prevent damage to property and are emphasized in this Manual
by terms defined here.
They are additionally identified by warning symbols (pictograms). The terms used in this
manual and the information on the product itself have the following meaning:
Danger
means that death, severe personal injury and/or substantial damage to property will occur if
the appropriate safety precaution are not observed.
Warning
means that death, severe personal injury and/or substantial damage to property can occur if
the appropriate safety precaution are not observed.
Caution
Means that slight personal injury and/or damage to property can occur if the appropriate
safety precautions are not observed.
Note
Is an important information on the product itself, the handling of the product or the
respective part of the Manual to which particular attention should be paid.


ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 7/35

Information for the user
1.4 Approved Use
Approved use in the sense of this Manual means that the ETL-series unit may only be used for
the applications described in the Brochure and in the Technical Description (see also Chapter
3 of this Manual) and only in conjunction with other devices and components which have
been recommended or approved of by ORION.
The product described in this Manual has been developed, manufactured, tested and
documented taking into account the appropriate safety standards. No danger therefore exists
in the normal case with respect to damage to property or the health of the persons if the
handling guidelines and safety information described for configuring, assembly, approved use
and maintenance are observed. This device has been designed such that safe isolation is
guaranteed between the primary and secondary circuits. Low voltages which are connected
must also be generated using safe insulation.
Warning
Following removal of the frontal cover, or after opening the cabinet door of ETL3000 unit,
certain parts of the device/system are accessible which may carry dangerous voltages.
Therefore only suitably qualified personnel may work on this device. These must be
thoroughly acquainted with all sources of danger and the maintenance measures as described
in this Manual.
1.5 Qualified Personnel
Severe personal injury and/or extensive damage to property may occur following unqualified
work on the device/system or the failure to observe the warnings described in the manual or
on the device/system cabinet. Therefore only suitably qualified personnel may work on this
device/system.
Qualified persons in the sense of the safety information present in this Manual or on the
product itself are persons who:
•are either familiar as configuring engineers with the safety concepts of automation
technology
•or have been trained as operators in the use of automation technology equipment
and are acquainted with the content of this Manual which refer to operation
•or have been appropriately trained as commissioning and/or maintenance personnel
for such automation technology equipment or are authorized to energize, ground and
tag circuits and devices/systems in accordance with established safety practices.
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 8/35

Information for the user
1.6 Warranty information
Your attention is drawn to the fact that the contents of this Manual are not part of a previous
or existing agreement, commitment or statutory right and do not change these. The warranty
conditions applied in the sales contract are neither extended nor limited by the contents of
this manual.
1.7 Supply and Delivery
The respective scope of delivery according to the valid contract is listed on the shipping
documents accompanying the delivery.
When opening the packaging, please observe the corresponding information on the packaging
material, Check that the delivery is complete and undamaged. In particular, compare the
Order Nos. on the rating plates (if present) with the ordering data.
Please retain the packaging material if possible so that you can reuse it if is necessary to
return the device. A form for this purpose can be found in Chapter 9.
1.8 Standards and Regulations
The harmonized European standards have been applied as far as possible to the specification
and production of this device. If no harmonized European standards have been applied, the
standards and regulations for Italy apply (see also technical data in chapter 3).
When using this product outside the range of applicability of these standards and regulations,
the appropriate standards and regulations in the country of use must be observed.
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 9/35

Information for the user
1.9 Declaration of Conformity
This declaration applies to ETL series air quality monitor as manufactured by ORION Srl.
We hereby declare that our product, type:
Con la presente dichiariamo che il nostro prodotto tipo:
Hiermit erklären wir, daß unser Produkt, Typ:
Nous déclarons par la présente que notre produit, type:
Por la presente declaramos que nuestro producto, tipo:
Com a presente, declaramos que o nosso produto, tipo:
Hiermee verklaren wijdatonsprodukt, type:
Hermederklaerer vi, at voresproduktaf typen:
τηνπαρσυσαδηλωνουµεοτιτοπροιονµαςτυπου
Härmedförsäkrar vi attvarprodukt, typ:
Taten vkuutamme, ettätuotteemme, tyyppi:
ETL 3000
Air quality monitor, fixed installation
ETL ONE
Air quality monitor, fixed installation with PM module
ETL BUS
Air quality monitor, for mobile installation
complies with the following relevant provisions:
è conforme alle seguenti particolari disposizioni:
folgenden einschlägigen Bestimmungen entspricht:
correspondauxdispositionspertinentessuivantes:
satisface las disposiciones pertinentes sigiuents :
esta em conformidade com as disposisões pertinentes, a saber:
voldoetaan de eisen van de in hetvervolggenoemdebepalingen:
overholderfØlgende relevante bestemmelser:
αυταποχpιεταιστσυςαχολουθουςσχετιχουςχανονισµους:
uppfyllerföljandetillämpligabestämmelser:
täyttääseuraavatasiaankuuluvatvaatimukset:
•
Low voltage guidelines (73/23/EEC and 93/68/EEC)
•
EMC guideline (89/336/EEC ad 93/68/EEC)
Applied harmonized standards, in particular: EN50081-1
EN50082-2
EN61010
•
Vibration Testing with Shaker
Sine (DIN IEC 68-2-6)
Random (DIN IEC 68-2-64)
Conformity was tested by :TÜV - report n° V02/23 dated 04/03/2002.
Unitecis a brandof :
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 10/35

Technical Description
2Installation Guidelines
2.1 Safety Information
Warning
Certain parts in the ETL carry dangerous voltages. The housing must be earthed and closed
before switching on the instrument.
2.2 General
The ETL3000 /ETLONE monitor should be installed in a place suitable for the type of
application and always outdoor so that the sensors contained in the ETL3000 /ETLONE are in
contact with the open air to be monitored.
The ETL3000 /ETLONE is supplied with mounting kit to be installed in a fixed execution (to be
mounted on a pole or on a wall).
The ETLBUS version can be supplied for a fixed installation or to be mounted on board a
vehicle (as a bus) for a “dynamic monitoring.
See chapter 2.5 for instruction on both type of installation.
Note
The SENS-IT (TF-MOS – Thick Film Metal Oxide Semiconductor) sensors included in the ETL
can be “drugged” and damaged by certain substances. In order to avoid any contamination of
the sensors, extremely care must be taken in NOT using any silicone or silicone compounds
nearby the sensors and inside and outside the ETL.
Also other compounds could alter the measurements of the TF-MOS SENS-IT sensors as:
-nitric compounds: varnish, solvents, PAN (aromatics ), paints, glues.
Alterations could affect the sensors also in indoor environments.
Furthermore extraordinary events could determine the momentary affection of
measurements due to the influences of the above substances.
DO NOT USE any of the above derived material on any parts of the ETL, or on its accessories
(mounting kit, screws, nuts, etc..)
If necessary ONLY use inert material as PTFE.
DO NEVER expose the sensors in direct contact or nearby substances as silicones, glues,
varnishes or their vapours.

ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 11/35

Technical Description
2.3 Electric Connection
Equipment rating:
•
220 V - 50 Hz (mains cable is supplied approved by CEI regulation)
•
110V -60 Hz (mains cable is supplied approved by CEI regulation)
•
Optionally : 12 V (cable is not supplied)
•
Absorption (without sensors and accessories): 220 V – 50 Hz 0,1 A
12 V 1,1 A
ETL is provided with a main switch having a protection 2A fuse (220 V) or 3A fuse (12V)
Before operating the instrument, check:
•The correct rating to be used (check the power supply note on the label of ETL)
•That a protective earth is installed
•The integrity of the mains cable
All wiring must be in accordance with local norms and be carried out by experienced
personnel.
2.4 Connection of input signals
The microprocessor board of the ETL3000/ETLONE can be set to receive 36 input 0-5V signals.
This option should be activated at Orion’s factory only by ORION’s personnel.
If required, please contact ORION’s service department.
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 12/35

Technical Description

2.5 Installation
ETL3000 /ETLONE is provided with a mounting kit and can be mounted :
•on a pole (diameter between 40,6mm and 190,5 mm) (1,6”-7,5”)
•on a wall for a fixed installation
The ETLBUS version can be mounted on board a vehicle, for a “air quality dynamic
monitoring”
2.5.1 Fixed installation
The mounting kit provided with ETL3000/ETLONE can be used both for pole or wall
mounting:
For wall mounting: use stainless steel screws.
The mounting kit is provided with fixing brackets suitable to be dimensioned for any pole
diameter.
Check that ETL is mounted with its axis perpendicular to the ground in order
to avoid any water infiltration.
Mounting kit
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 13/35

Technical Description
3Technical Description
3.1 ETL: TECHNICAL DATA
TECHNICAL SPECIFICATIONS ETL
Dimensions
ETL3000: 370 x 520 (h) x 210 mm ETLONE: 530 x 690 (h) x 210 mmm
Weight: 10 Kg /15 Kg
Enclusure/Execution: Aluminium (standard) - IP54 – outdoor installation.
Mounting kit: ETL3000/ETLONE is supplied with pole mounting kit
Sensors
TF-MOS – Thick Film Metal Oxide Semiconductor for: CO, NO
2
, O
3
, C
6
H
6
, CH
4
,
Electrochemical sensors: NH3, SO2, H2S, VOC
max five sensors at same time in the ETL3000
max seven sensors at same time in the ETLONE
Operative conditions Temperature: -20°C to 60°C (standard)
Relative Humidity: 10 to 95%, non-condensing
Air conditioning Not needed
Data logger:
Microprocessor
with Flash memory,
1 data/second acquired as elementary data for each sensor.
Calculation of the minute average,
Storage of hourly or, if requested, 15 minutes data
watch dog on board,
1 Mb memory RAM,
1 Mb flash memory,
4 x RS232 available,
16 D.O.; 15 D.I.
Firmware can be upgraded by remote connection.
Sampling rate 1 sec
Power supply:
Standard 110-220V ac 50-60Hz
Optional 12Vdc
Power consumption: 50 W (with 5 sensors, meteo and GSM-UMTS modem)
Calibration 12/18 months (site dependent)
Air Flow
Free flow
(Doesn’t need external pump and maintenance)
210 mm
530 mm
690 mm
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 14/35

Technical Description
3.1.1 Optional accessories – Technical data
OPTIONS for ETL unit
Dust monitoring (ETL ONE)
The following choices are available for PM 10 and/or PM 2.5 monitor
Built-in monitor in the ETLONE case:
1) ETL-One PDR: with built-in PDR1500 (0-400 ug/m3)either PM 2.5 or PM 10
2) ETL-One ETLS : Unitec light scattering (0-1500 ug/m3 for either PM2.5 or PM10)
3) ETL-One DST : built-in light scattering (TSI) for PTS, PM10, PM4, PM2.5, PM1
External PM monitor to ETL case:
4) OSIRIS (0-600 ug/m3 for PM1-PM2.5) and (0-6000ug/m3 for PM10 and PTS)
5) APM2 : PM10, PM2.5 CERTIFIED ACCORDING TO EN:12341
Noise sensor dB 3000 Sound level meter Class 1 with 60 dB dynamic range
Data Transmission Modem (RF, GSM, GPRS, UMTS) or Ethernet (LAN, WLAN)
Software: @COM3000 remote data handling and elaboration software (report, graphs, statistics,
configuration)
Meteorological parameters Wind direction, Wind speed, Temperature, Humidity, Pressure, Rain fall, Solar radiation, UV
radiation (last two parameters are optional)
Solar panel and battery kit
Solar panels, battery, regulator for 24 hours autonomy.
This kit is designed to power an ETL with up to 5 sensors, modem GSM and a
meteorological station.
In case the ETL is ordered with the solar panel and battery kit, the ETL will be powered
only at 12V C.
The box with battery supplied with the ETL can be main powered at 220V or powered at
12VDC from the solar panel. The battery will power the ETL and/or the dust module at
12VDC.
Solar Panel
Nominal output Solar Panel (P max): 150 W
Voltage at P max (Vmp): 17,64V
Current at P max (Imp): 8,50A
Open Circuit Voltage (Voc): 21,17V
Short Circuit Voltage (Isc): 9,51A
Cell Efficiency: 17,12%
Module Efficiency: 15,02%
Solar Cells: 36 (4x9)
Cells Dimensions: 156 x 156mm (6 x 6”)
Dimensions: 1482x 674 x 35 mm (58,3 x 26,5 x 1,4 “)
Weight: 9,9 Kg (21,82 lb)
Battery
Nominal Voltage: 12 V
Capacity (20Hr at 25 °C): 100 Ah
Length: 330 mm (12,99 “)
Width: 171mm (6,73”)
Height: 220mm (8,66”)
Approx. Weight: 30 Kg (66,14 lb)
Nominal Operating temperature: 25°C + 3°C ( 77°F+ 37,4°F)
Operating Temperature Range: -15°C + 50°C ( 5°F + 122°F)
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 15/35

Technical Description
3.2 A
pplications
The ETL3000 /ETLONE is the innovative air quality monitoring
solution designed and manufactured by ORION for indicative
measurement (as defined by European Directive 2008/50/EC).
The ETL3000 /ETLONE is a multiparametric station equipped
with Unitec SENS-IT sensors for continuous gas monitoring
with high precision and accuracy, featured by easy use and very
low ownership costs. The IP55 case permits easy and direct
outdoor installation (no cooling system or air treatment are
required!).
The Unitec SENS-IT gas sensors are based on proprietary
technology and can monitor continuously gas pollutants
in outdoor applications ensuring excellent sensitivity and
selectivity (also at ppb levels), with no needs of frequent maintenance or calibration.
Each SENS-IT sensor is specific for a single gas and independently connected to the datalogger
with plug-in connector, for easy in-field replacement. The ETL is equipped with internal
datalogger which handles all activities, including continuously data acquisition (1 data set per
second), hourly average storage and data transmission.
Many options are available: weather stations, GSM modem, UMTS modem (for VPN
connection), noise meter, solar panel kit, etc.
Different software solutions are also available for data download, data export, unit
configuration, geolocation, real-time visualization, etc.
A mounting kit is always supplied, suitable for any pole diameter.
A built-in data logger allows data memory of hourly or, if requested, 15 minutes averages.
APPLICATIONS (ONLY OUTDOOR):
1. URBAN AIR QUALITY- ROAD STREET POLLUTION:
•As an integration in the traditional air quality monitoring networks.
•ETL3000/ETLONE can be used to make a preliminary air quality monitoring to
evaluate the site where placing the traditional AQM stations
•Replace a traditional station where values are low and positioning that station in
more polluted areas
•use ETL3000/ETLONE to get many data from many points in the territory to validate
the air quality modelling software on pollution development
•integration with traffic control system
2. FENCELINE MONITORING - LANDFILL MONITORING (WITH OPTIONAL MEASUREMENT OF CH4,
H2S AND NH3).
3. ETL-BUS: MOBILE MONITORING OF TRAFFIC POLLUTION by positioning the ETLBUS on
the top of a car or on public transport vehicles, and monitoring air quality together
with geolocation system (GPS).
Maximum Charging Current: 30 A
Terminal Material Copper
Maximum discharge Current 800 A (5 s.)
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 16/35

Technical Description
3.3 Measuring principle of SENS-IT sensors
The Unitec SENS-IT sensors are innovative devices for environmental gas pollutants
monitoring, based on proprietary Thick Film Metal Oxide Semiconductor Technology (TF-
MOS)
Thick film sensors are devices of the last generation, used to convert a chemical physic
information into an electric signal.
Thick film sensors technology exploits electric conduction phenomena that happen above the
surface of nanostructured semiconducting metal
oxides (composed by micrograins of 20÷200 nm
diameter, depending on the sensor) at
temperature between 200 °C and 400 °C. An
electrical response from semiconductor is
obtained that is proportional to particular
atmospheric gas concentration; using a suitable
fitting calibration curve the response signal is
turned into gas concentration. In such conditions
atmospheric oxide adsorption took place above
semiconductor surface.
Our sensors are composed by an alumina substrate (2,5x2,5 mm), an
heating layer and a semiconducting metal oxide (sensible layer) whose
signal is collected by two electrodes. The heating element works even
as temperature regulator element in a feedback external circuit that
works in order to maintain its resistance value constant.
Sensor works at the same temperature in every atmospheric
conditions.
Alumina substrate can be electrically connected to a circuit device
(TO8) by gold wires (0,6 mm Ø) using bonding technique.
Some analogue and digital filters remove the sensors response from electrical noises.
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 17/35

Technical Description
A sensor is the result of a process to prepare a sensible layer
based on semiconductor oxides. The basic phenomena for is
functioning is the absorption on its surface of ions-oxygen
which react with the gases present in the atmosphere.
When a semiconductor based on type nmetal oxides
(conduction by electrons) is burned at a certain
temperature, the oxygen present in the atmosphere is
adsorbed as a ionic form on its surface.
The electrons in the conduction area of the above
semiconductors are transferred from the surface area to
the oxygen adsorbed, with the result of creating an empty
area around the surface. It is generated a surface
potential which acts as a barrier able to hinder the
electrons flow among the granes.
.
In presence of reducing gases, the density on the surface
of the negative charged oxygen decreases; in that way
the hight of the barrier in contact with the granes gets
lower, as evidenced in the Fig. 1.3.
The reduced barrier decreases the resistance of the
sensor (always for a semiconductor type n) which, at a
microscopic level, is detected and measured by specific
circuital elements.
On the other hand, in presence of oxydant gases the
reaction leads to a decreasing number of free electrons
and to an increase of the potential barrier and therefore
of the sensor resistance .
In the case of semiconductor typepthe behaviour could
be described similarly taking into account that those
with more charge are the gaps.
Fig 1.2 –Adsorbtion of Oxygen on the
surface an
d its effect on the border granes
Fig. 1.3 – Example of reaction with a
reducing gas (carbon monoxide)
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 18/35

Technical Description
REACTIONS OF CHEMICAL ABSORPTION
Reactions which occur between the oxygen in the atmosphere and the surface are the
following:
O2+ e-↔O2-(ads)
O2↔2 O(ads)
e-+ O(ads)↔O-(ads)
The reactions which occur in presence of a reducing gas are the following:
Red + O-(ads)→RedO-(ads)→RedO + e-
Red = reducing gas
ANALITICAL EXPRESSION OF THE SENSOR MEASUREMENT
The reaction between the resistance of the sensor and the concentration of the
reducing gas can be expressed by the following equation:
R = A[C]-α
R = electrical resistance of the sensor
A,α= constants
[C] = gas concentration
In terms of conduttance, the relation with the gas concentration is expressed by a
power law: :
Gg= Ga+ α[C]β
Gg = conductance in a gas
Ga= conductance in air
α, β= constant
[C] = gas concentration
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 19/35

Technical Description
3.4 Technical Specifications of sensors
PARAMETERS RANGE PRECISION RESOLUTION
SENS-IT
(TF-MOS – Thick
Film Metal Oxide
Semiconductor)
CO 0.1-80 ppm 0.2 ppm 0.1 ppm
NO2 10-250 ppb 10 ppb 1 ppb
O3 10-250 ppb 10 ppb 1 ppb
C6H6 0.1-30 ppb 0.2 ppb 0.1 ppb
CH4 1-1,500 ppm 5 ppm 1 ppm
SENS-IT
(EC -
Electrochemical
Technology)
NH3 7-100 ppm 0.3 ppm 0.1 ppm
SO2 5-10,000 ppb 20 ppb 1 ppb
H2S 2 -3,000 ppb 15 ppb 1 ppb
VOC 0.6-25 ppm 0.1 ppm 0.1 ppm
SENS-IT
(IR - Infrared
Technology)
CO2 10-5,000 ppm 50 ppm 1 ppm
Operating conditions
Temperature: -20 / +60°C
Relative Humidity: 5-95% (non condensating)
Zero/Span drift
< 2,5% / 6 months
< 2,5% / 3 months (for O3)
3.5 Technical Specifications of optional sensors
Parameter
Measuring range
Resolution
Linearity
Accuracy
Temperature -20°C - +50°C 0.1 °C +/- 0.2 °C +/- 0.3 °C
RH 0 – 100 % 0.1 % +/- 1 % +/- 2 %
Noise
Dinamic 60dB
45 – 120dB 1 dB +/- 0.5 dB Class 1
ORION S.r.l. ETL_Operation and Service manual_ 02_17.docx Pag. 20/2