Gas monitoring in-situ

CO concentrations of over 50 ppm in breathing air lead after a short time lead to impacts well-being, concentration and health. To avoid such impacts by a proper ventilation CO concentration in the tunnel’s driving area is monitored.

The sensor is directly mounted at the measuring point. Air is fed into an electrochemical gas sensor by a capillary. The CO gas reacts at the sensor’s sensing electrode and a current proportional to the gas concentration is generated.

Given this current the sensor calculates the gas concentration and shows it on its display in ppm. The output current depends on the chosen measuring range and the measured gas concentration.

The sensor by a menu guided process can be recalibrated with zero and reference gas such that long time drift can be compensated.

Request a quote

Would you like to request a quote for any of our products or services?

Please click below and leave your details. We will contact you as soon as possible.

t/ECS Gas sensor

  • Mounted directly in the tunnel’s driving area
  • Electrochemical sensing of the gas concentration
  • Sensor cells for different gases: CO, NO, NO2 and others
  • Passive, analogue 2-wire transmitter 4-20 mA
  • LCD to display measured value
  • Selectable measuring range
  • Menu guided recalibration with zero and reference gas without the need to open the sensor housing
  • Simulation of output values
  • Available either in wall-mounted or flush-mounted stainless steel housing or with a stainless steel cover if the inner sensor housing is mounted behind an existing panel
  • Protection against splash water and water jets during tunnel wash events
  • Electrochemical sensor in ABS plastic housing with display and membrane keypad
  • Stainless steel housing or cover panel for protection against splash water and water jets
  • Connection either to tunnel control system, evaluation unit or visibility sensor
  • Speziell für die Anwendung in Tunnels entwickelt
  • Robustes Edelstahl Gehäuse mit Schwallwasserschutz unempfindlich gegen Korrosion und Tunnelwäsche
  • Wartungsarm, empfindlich, stabil und genau
  • Flexible Integration in die Tunnel­leit­technik
  • RVS konforme Montagehöhe realisierbar
  • Sensorzelle menügeführt wieder abgleichbar
Technische Daten
Gas measurement
Measuring method Electrochemical gas analysis
Measured value Gas concentration in ppm
Measuring range Selectable, typically (default):
0 .. 300 ppm CO
0 .. 20 ppm NO2
0 .. 50 ppm NO
Resolution 1 ppm CO, 0,1 ppm NO2, 0,5 ppm NO
Long term drift < 5 % per year
T90 time < 30 s
Temperature range -20 .. +50 °C, sensor temperature compensated
Pressure range 900 .. 1100 hPa
Humidity range 15 .. 90% relative humidity (non condensing)
Type t/ECS
Power supply 24 VDC via current loop
Housing materal Glass bead reinforced polyamide (PA 6 30% GK)
Dimensions 64 x 98 x 34 mm
Protection class IP 64
Weight ca. 160 g
Analogue output 4 – 20 mA
Wall-mounted housing
Type t/ECS-AP
Housing material Edelstahl V4A 1.4571
Dimensions 200 (250) x 200 x 118,5 mm
Protection class IP 66 (sensor in housing)
Weight ca. 3 kg
Electrical standards 2006/95/EG Niederspannungsrichtlinie (LVD)
2004/108/EG Elektromagnetische Verträglichkeit (EMV)
IEC 61326-1:2012
IEC 61010-1:2010
Tunnel safety AT: RVS 09.02.22
DE: RABT 2006
CH: ASTRA RL 13001, Fachhandbuch BSA
Gas monitoring AT: ÖNORM M9418, ÖNORM M9419
DE: VDI 2053


Product info DE (PDF, 340 kB)
Product info EN (PDF, 340 kB)


System setup


Gas sensor t/ECS

The gas sensor is mounted in a height of about 1.5 m above the carriageway.


Visibility sensor VisGuard

The gas sensor t/ECS can be either connected to the visibility sensor VisGuard or directly to the tunnel control system.


Connection to tunnel control system
The gas sensor t/ECS can be directly connected to the tunnel control system through its analogue output. When used together with the visibility sensor VisGuard the system can be connected via analogue outputs or via RS-485 MODBUS RTU.