Tunnel and Traffic Monitoring

Robust air flow monitoring system based on high-precision differential pressure measurement
2-point mesh
Automatic zeroing of differential pressure transducers
Touch evaluation and control unit to display measured values, status and set parameters
Connection to tunnel control system by RS-485 MODBUS RTU, optionally by analogue outputs and relay contacts

Accurate ultrasonic air flow measuring system based on different transition times of ultrasonic pulses
Measurement of average air flow over the whole tunnel cross section
Sensor setup via service interface
• Suitable for tunnel cross sections up to 18 m (Measuring path up to 25 m)
Connection to tunnel control system either via analogue output and relaysor via RS-485 MODBUS RTU
Visible LEDs to indicate sensor status
Corrosion-resistant non-wearing polyamide membranes
Optional, remote touch operating unit to display measured values and to modify parameters

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 IP69K
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

Smart IoT enabled gas sensor
Electrochemical measurement of gas concentration with up to 4 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
Stainless steel housing 1.4404 (AISI 316L)
Sensor protected against splashing of water and powerful water jets used for tunnel washing
IP rating IP69K
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

Zoom lens to adjust the focus areas
Sensor with V(λ) filter and silicon photo element
Temperature compensated and long term stable amplifier for the photoelectric current using live zero
Heated housing IP 67 made from stainless steel 1.4404
Electronically controlled heating and temperature monitoring
Mounting flange to adjust horizontal and vertical angle
Fault indication by relay isolated (NC)
Optional second outut channel for increased resolution at low lighting levels
Surge protection

Visibility measurement by optical transmission method
Reliable measurement along a path of 10 m parallel to the tunnel axis
Parametrisation of the sensor via Modbus RTU
External cable length of 1000 m to tunnel control system
Signal output either via analogue and relay outputs or RS-485 with MODBUS RTU protocol
Visible LEDs show sensor status