Siemens QFA3171 OUTSIDE AIR RH AND TEMP SENSOR, 2 PERCENT, RH: 4-20 4 TO 20 MA T: 4-20 MASiemens QFA3171 Outside Air RH and Temp Sensor, 2 percent, RH: 4 20 4 to 20 Ma T: 4 20 mA This Q Series Outdoor Air Relative Humidity and Relative Humidity Temperature Sensor monitors and transmits changes in humidity and temperature to the building control system. This unit is especially suited for HVAC applications where high accuracy and short response times for measuring relative humidity are required. This sensor has a 2 percent accuracy, a 4 to