Q-Series 
Technical Instructions
Document No. 155-755
February 28, 2013
 
Relative Humidity and 
Relative Humidity & 
Temperature Sensors for 
Critical Environments 
and Outdoor Air 
     
 
Siemens Industry, Inc. 
Description 
The Q-Series Relative Humidity and Relative Humidity & Temperature Sensors for 
Critical Environments and Outdoor Air monitor and transmit changes in humidity and 
temperature to the building control systems. 
Features 
•  Operating voltage 24 Vac/13.5 to 35 Vdc 
•  Signal output 0 to 10 Vdc/4 to 20 mA for relative humidity and temperature 
•  Very high measuring accuracy across the entire measuring range 
•  Capacitive humidity measurement 
•  Precise, stable humidity sensing 
•  Available in 2% and 2%, certified models 
• Optional display 
•  Recalibration service available (QFA41 Series only) 
Application 
The Q-Series Outdoor Air rh and rh/T Sensors are for use in HVAC applications where 
high accuracy and short response times for measuring relative humidity are required. 
The measuring range covers the entire humidity range of 0 to 100%. Some application 
examples: 
•  Storage and production facilities in the paper, textile, pharmaceutical, food, chemical 
and electronics industry, etc. 
• Laboratories 
• Hospitals 
•  Computer and EDP centers 
• Greenhouses 
•  Outdoor use requires AQF3100 Outdoor Mounting Kit