smart/AQM Air Quality Monitor

Monitoring of air quality – visibility and gases

Visibility measurement is used to control the ventilation of a tunnel in normal operation. Whether and at what power artificial ventilation is provided by jet fans depends on the measured visibility turbidity values.

Visibility is expressed by the extinc-tion coefficient, which describes the light attenuation caused by particles in the air.

The visual turbidity sensor draws in air from the tunnel using the integrated fan and measures the intensity of the light that is scattered at an angle of 30° when it falls on the sample drawn in inside the device. The scattered light is compared to the light passing directly through. The extinction coefficient is calculated from the value of the intensity of the scattered light using a factor.

The optional electrochemical gas sensor cells generate currents proportional to the prevailing gas concentration. The sensor uses these currents and the measured temperature to calculate the gas concentrations.

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Features

Smart IoT enables visibility and gas sensor
Scattered lightvisibility sensor
Dual beam method to compensate soiling and ageing
Optional up to 3 electrochemical gas sensor modules
Pre-calibrated gas sensor modules for different gases and measuring ranges, including CO, NO, NO₂, SO2
Installation in-situ in the tunnel’s driving area or extractive with hose adapters
Active extraction of sample air by integrated fan
Integrated purge air system
Optional sample heater to eliminate fog from measurement
Stainless steel housing 1.4404 (AISI 316L)
Sensor protected against splashing of water and powerful water jets used for tunnel washing
IP rating IP69
Optional LCD in housing cover
Integrated web server for visualisation, configuration, data logging, remote maintenance
Connection to tunnel control system by
- MODBUS/TCP (Ethernet)
- MODBUS RTU (RS-485)
- Analogue and relay outputs (optional)
- OPC UA (Ethernet)
Optional smart/HUB IoT operating and control unit with touch display

System

Advantages

Specifically designed for application in tunnels
Single sensor instead of transmitter/receiver pair requiring exact alignment
Effective fog eliminationby optional heater
Easy recalibration by calibration plug
Internal purge air system keeps optics clean and prevents long-term drift
Robust stainless steel housing for protection against corrosion and water jets
Permanent condition monitoring
Remote maintenance
Low maintenance requirements, stable, accurate
Pre-calibrated gas sensor modules for easy exchange
Flexible integration into tunnel control system
Ethernet port
Mounting height in accordance with Austrian RVS
Menu guided recalibration of gas sensor modules
Smart IoT solution from sensor over hub to asset management software

Technical Specifications

Sensor device

Sensor device smart/AQM (Basic variant)
Type	smart/AQM
Variant	Basic (visibility only, no Ethernet connectivity)
Measuring method	Dual beam scattered light
Light source	Laser, class 2 in accordance with EN 60825-1 < 1 mW at 650 nm
Measured value	Scattered light intensity expressed as extinction coefficient, transmission, etc.
Measuring range	Configurable typically 0 .. 15 / km
Resolution	0.001 / km
Accuracy	0.01 / km
Power supply	24 VDC ± 10 %
Current consumption	max. 800 mA (without heater) @ 24 VDC max. 2 A @ 24 VDC (with heater)
Appliance class	Class III (PELV)
Material	Stainless steel 1.4404 (AISI 316L)
IP rating	IP 69
Dimensions	300 x 220 x 100 mm
Weight	approx. 5.8 kg
Analogue/relay outputs (standard)	3 x 4 – 20 mA (2-wire, active) 3 x SPST-NO (max. 60 VDC / 25 VAC, max. 0.5 A)
Temperature range	-40 .. +60 °C
Pressure range	640 .. 1060 hPa
Humidity range	0 .. 100% relative humidity (non-condensing)
Storage temperature	-40 .. +85 °C (without gas sensor modules)

Sensor device smart/AQM (Standard and Smart variant)
Type	smart/AQM
Variants	Standard / Smart
Gas sensor ports	up to 3 (to be specified on order)
Measuring method	Visibility: Dual beam scattered light Gas: electrochemical gas sensor cells
Light source	Laser, class 2 in accordance with EN 60825-1 < 1 mW at 650 nm
Measured values	Visibility: Scattered light intensity expressed as extinction coefficient, transmission, etc. Gas: concentration
Measuring range	Visibility: Configurable, typically 0 .. 15 / km Gas: depending on installed gas sensor modules
Resolution	Visibility: 0.001 / km Gas: depending on installed gas sensor modules
Accuracy	Visibility: 0.01 / km Gas: depending on installed gas sensor modules
Power supply	24 VDC ± 10 %
Current consumption	max. 1.1 A @ 24 VDC (without heater) max. 2.3 A @ 24 VDC (with heater)
Appliance class	Class III (PELV)
Material	Stainless steel 1.4404 (AISI 316L)
IP rating	IP 69
Dimensions	300 x 220 x 100 mm
Weight	approx. 6.2 kg
Digital interfaces (standard)	MODBUS RTU (RS-485) MODBUS/TCP (Ethernet) Webserver for configuration (Ethernet)
Analogue/relay outputs (standard)	3 x 4 – 20 mA (2-wire, active) 3 x SPST-NO (max. 60 VDC / 25 VAC, max. 0.5 A)
Additional analogue/relay outputs (optional)	up to 2 analogue / relay output modules, each: 3 x 4 – 20 mA (2-wire, active) 3 x SPST-NO (max. 60 VDC / 25 VAC, max. 0.5 A)
Temperature range	-40 .. +60 °C
Pressure range	640 .. 1060 hPa (visbility only) 900 .. 1060 hPa (with gas sensor modules)
Humidity range	0 .. 100% relative humidity, non-condensing (visbility only) 15 .. 95% relative humidity, non-condensing (with gas sensor modules)
Storage temperature	-40 .. +85 °C (without gas sensor modules)

Terminal box

Terminal box - smart/AQM-TBX
Type	smart/AQM-TBX
System cable port	1 (for smart/AQM)
Power supply	100 to 240 VAC, 50/60 Hz
Supply voltage fluctuations	± 10 %
Overvoltage category	II
Power rating	60 W
Appliance class	Class I
Material	Stainless steel 1.4404 (AISI 316L)
Mounting	incl. mounting clamp made from Stainless steel 1.4404 for wall mounting
IP rating	IP 69
Dimensions	250 x 160 x 110 mm
Weight	approx. 3.2 kg
Indoor/Outdoor use	Indoor use (tunnel)
Altitude	up to 2,000 m
Temperature range	-40 .. +60 °C
Humidity range	0 .. 100% relative humidity (non-condensing)
Pollution degree	4 (intended environment) / 2 (when cover removed)

Gas sensor modules

Gas sensor module CO-500
Type	smart/ECS-CO-500
Measuring method	Electrochemical cell
Measured value	Gas concentration in ppm
Measuring range	Configurable within 0 .. 500 ppm CO typically 0 .. 300 ppm CO
Maximum overload	1,000 ppm CO
Lower detectable limit	< 0.5 ppm CO
Resolution	0.1 ppm CO
Accuracy	± 2 ppm or 2 % reading³⁾
Temperature compensation	yes
T90 time	< 40 s
Long term drift	< 2 % signal loss per month
Dimensions	∅ 38 x 74 mm
Weight	88 g
Expected operation life	3 years in air
Storage life	6 months in packaging
Storage temperature	5 .. 20 °C

Gas sensor module NO2-2
Type	smart/ECS-NO2-2
Measuring method	Electrochemical cell
Measured value	Gas concentration in ppm
Measuring range	Configurable within 0 .. 2 ppm NO₂ typically 0 .. 2 ppm NO₂
Maximum overload	10 ppm NO₂
Lower detectable limit	0.05 ppm NO₂
Resolution	0.02 ppm NO₂
Accuracy	± 0.05 ppm or 5 % reading⁴⁾
Temperature compensation	yes
T90 time	< 60 s
Long term drift	< 2 % signal loss per month
Dimensions	∅ 38 x 74 mm
Weight	88 g
Expected operation life	2 years in air
Storage life	6 months in packaging
Storage temperature	5 .. 20 °C

Gas sensor module NO2-20
Type	smart/ECS-NO2-20
Measuring method	Electrochemical cell
Measured value	Gas concentration in ppm
Measuring range	Configurable within 0 .. 20 ppm NO₂ typically 0 .. 10 ppm NO₂
Maximum overload	200 ppm NO₂
Lower detectable limit	< 0.15 ppm NO₂
Resolution	0.05 ppm NO₂
Accuracy	± 0.5 ppm or 2 % reading⁵⁾
Temperature compensation	yes
T90 time	< 60 s
Long term drift	< 2 % signal loss per month
Dimensions	∅ 38 x 74 mm
Weight	88 g
Expected operation life	2 years in air
Storage life	6 months in packaging
Storage temperature	5 .. 20 °C

Gas sensor module NO-100
Type	smart/ECS-NO-100
Measuring method	Electrochemical cell
Measured value	Gas concentration in ppm
Measuring range	Configurable within 0 .. 100 ppm NO typically 0 .. 30 ppm NO
Maximum overload	200 ppm NO
Lower detectable limit	1 ppm NO
Resolution	0.05 ppm NO
Accuracy	± 0.5 ppm or 2 % reading⁶⁾
Temperature compensation	yes
T90 time	< 10 s
Long term drift	< 2 % signal loss per month
Dimensions	∅ 38 x 74 mm
Weight	88 g
Expected operation life	3 years in air
Storage life	6 months in packaging
Storage temperature	5 .. 20 °C

Gas sensor module NO-25
Type	smart/ECS-NO-25
Measuring method	Electrochemical cell
Measured value	Gas concentration in ppm
Measuring range	Configurable within 0 .. 25 ppm NO overload up to 0 .. 30 ppm NO
Maximum overload	50 ppm NO
Lower detectable limit	< 0.4 ppm NO
Resolution	0.05 ppm NO
Accuracy	± 0.2 ppm or 2 % reading⁷⁾
Temperature compensation	yes
T90 time	< 10 s
Long term drift	< 2 % signal loss per month
Dimensions	∅ 38 x 74 mm
Weight	88 g
Expected operation life	3 years in air
Storage life	6 months in packaging
Storage temperature	5 .. 20 °C

Probe heater

smart/AQM-PHT Probe heater option
Type	smart/AQM-PHT
Control	Controlled by outside temperature (if smart/AQM-TMP installed), otherwise by internal temperature (offset configurable)
Fog concentration	max. 5 g/m³ in saturated air
Temperature range	-40 .. 60 °C
Material	Stainless steel 1.4404 (AISI 316L)
IP rating	IP 69
Dimensions	∅ 64 x 335 mm
Weight	Heater 1.5 kg Holder 0.4 kg

Analogue / relay output module

Analogue / relay output module ARO
Type	smart/CORE-ARO
Analogue outputs	3 x 4 - 20 mA
Analogue output type	2-wire, active
Relay outputs	3 x SPST-NO
Max. contact rating	max. 60 VDC / 25 VAC, max. 0.5 A

2.4" Touch display

2.4“ Internal touch display D2
Type	smart/CORE-D2
Display type	TFT colour
Diagonal screen size	2.4” (60.96 mm)
Display area	49.96 x 37.72 mm
Resolution	320 x 240 px
Touch type	capacitive
Backlight	LED - white

Temperature sensor option

smart/AQM-TMP Temperature sensor option
Type	smart/AQM-TMP
Temperature sensor	Pt100 DIN B, R₀: 100 Ω, Temperature coefficient: 3.850 x 10^-3/°C, Standard: DIN EN 60751
Sensor sleeve material	Stainless steel 1.4571 (AISI 316Ti)
Cable material	Silicon
IP rating	IP 69 (installed in smart/AQM)
Cable length	30 cm (longer on request)
Temperature range	-60 .. +180 °C
Humidity range	5 .. 95% relative humidity (non-condensing)
Storage temperature	-30 .. +70 °C

Temperature and humidity sensor

Temperature and humidity sensor
Type	smart/CORE-TRH
Measured values	Temperature, Relative humidity
Calculated variables	Dew point, Frost point, Wet bulb temperature, Ice bulb temperature, Water vapour partial pressure, Mixture ratio, Absolute humidity, Specific enthalpy
Measuring ranges	Temperature: -40 .. 80 °C Relative humidity: 0 .. 100 %
Accuracy	Temperature: ±(0,2 °C + 0,67 % * abs (reading - 20 °C)) Relative humidity: -15 .. 40 °C: ± (1.3 + 0.3 % reading) %RH for RH ≤ 90 %, ± 2.3 % %RH for RH > 90 % -40 .. 80 °C: ± (1.5 + 1.5 % reading) %RH
Resolution	Temperature: 0.01 °C Relative humidity: 0.01 %RH
T90 time	< 15 s with stainless steel grid filter at 20 °C
Current consumption	3 mA
Housing material	Stainless steel 1.4404 (AISI 316L)

Conformities

Conformities
Markings
Electrical standards	2014/35/EU Low Voltage Directive (LVD) 2014/30/EU Electromagnetic compatibility (EMC) EN IEC 61000-6-2:2019 Immunity standard for industrial environments EN IEC 61000-6-3:2007 + A1: 2011 Emission standard for residential, commercial and light-industrial environments EN 61010-1 Safety requirements for electrical equipment for measurement, control and laboratory use EN 61326-1 Electrical equipment for measurement, control and laboratory use - EMC requirements
Tunnel safety standards	Austria: RVS 09.02.22 Germany: RABT 2006 Schweiz: ASTRA 13001 Lüftung der Strassentunnel (2021), ASTRA 13004 Branddetektion in Strassentunneln (2007), ASTRA 23001 Fachhandbuch Betriebs- und Sicherheitsausrüstungen Norway: Norwegian Public Roads Administration Handbook No. 021 Road Tunnels International: ISO 23431 Measurement of road tunnel air quality
Gas monitoring	Europe: EN 50545-1 Austria: ÖNORM M9419 Germany: VDI 2053

¹⁾

no smoke detector in the sense of EN 54-7 Fire detection and fire alarm systems - Part 7: Smoke detectors - Point-type smoke detectors using the scattered light, transmitted light or ionisation principle

²⁾

only Standard and Smart variant

³⁾ , ⁴⁾ , ⁵⁾ , ⁶⁾ , ⁷⁾

whichever is greater