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KOBOLD Instruments Inc • 1801 Parkway View Drive • 15205 Pittsburgh, PA • Tel: +1 412 788 2830 • E-mail: info@koboldusa.com • visit koboldusa.com
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Humidity / Temperature Measuring Instrument AFK-G
Capacitive method of measurement
Measuring range:
Temperature: 0 ... +200°C
Humidity: 0 ... 100% rH
pmax: 25 bar
tmax: +200°C
Output: 2x 4 - 20 mA
Accuracy:
Temperature: ±0,1°C
Humidity: ±2 % rH
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Datasheet
Operating Instructions
Miscellaneous
Description
The range AFK-G humidity/temperature sensors are sensors for measuring relative humidity and temperature (optional) in air and other non-aggressive gases for an operating temperature of up to 200 °C. The high pressure variant can be used up to a pressure of 25 bar. The sensors are thus ideally suited for measuring humidity in industrial processes. The sensors are based on capacitive metrology which is reasonably-priced, maintenance-free and highly accurate.
Capacitive humidity sensor elements form the basis of these sensors. An electrode system, a moisture-sensitive polymer layer and a gold layer that is permeable to vapour are situated on a small thin glass or ceramic substrate. Since the hygroscopic polymer layer can absorb water molecules that alter its dielectric constant, this layered system acts as a moisture-dependant capacitor, whose capacitance is a measure of the surrounding relative humidity.
The change in capacitance is converted to an electrical output signal by electronics normally mounted on the humidity sensor element. Both parts form a capacitive humidity sensor that can be adjusted using humidity references. Accuracy is approximately ± 2% rH. The transmitters offer a 4 - 20 mA analogue output for relative humidity and a second 4 - 20 mA output for temperature when specified.