Intelligent Passive Road Sensor Passive road sensor IRS31 is flush-mounted in the road. The two part housing design allows the combined sensor/electronics unit to be removed for maintenance or calibration at any time. The following variables are recorded: • Road surface temperature • Water film height up to 4 mm • Freezing temperature for different de-icing materials (NaCl, MgCl, CaCl) • Road condition (dry/damp/wet/ice or snow/residual salt/freezing rain) • Friction (grip) • Ice percentage Optional • 2 additional depth temperatures The sensors are addressable and can be networked. The measurement data is available for further processing in the form of a standard protocol. Road (runway) dampness Unit: dry/damp/wet Slippery road (runway) conditions Unit: no ice / snow, snow, freezing rain, ice Technical data Dimensions Detectable road (runway) conditions dry, dump, wet, ice or snow, residual salt content, freezing wetness Rated current RS485, baud rate: 2400 to 38400 bit/s (default: 19200) Protection type Power supply Replaceable sensor electronics Polling via RS485 interface Low energy consumption (solar operation) Radar principle to measure water film Analogue outputs Freezing point Storage temperature Measuring range ±0.5 °C (0 °C to −2.5 °C), else ±20 % of average value (at de-icing agent NaCl) Water film height Principle Measuring range Operating temp. Operating relative humidity Road (runway) surface temperature Friction (Grip) [slippery...dry] Measuring range Measuring range Measuring range