Lufft’s IRS21 is a passive

sensor that monitors road

surface temperature, freezing

temperature for NaCl (others on

request), road condition (dry/

damp/wet/ice or snow / residual

salt/freezing), and water film

level (up to 4 mm). This

intelligent road surface sensor

is a primary component of our

Road Weather Information

Stations (RWIS). When used in

an RWIS application, the IRS21

is connected to a CR800,

CR850 or CR1000 datalogger

via the SDM-SIO1 Serial Data

Interface Module.