Since the AirBoss is limited to +/- 2,000 fpm, we needed a high velocity air velocity sensor for use in fan discharge and ventilation air shafts – i.e. 0-24,000 fpm. Choosing to use the pitot tube method, a differential pressure signal is measured in inches of water gauge. But mine supervisors need to calculate volume of air flow, usually in cfm.  Because the pitot tube pressure is highly non-linear -- requiring math to convert to fpm -- our software team developed software code to convert non-linear inches of WG to linear fpm. The MultiBoss-HV therefore has a 4-20ma linear output, and the display on the front panel reads directly in fpm.