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.