Ambient Air quality Monitoring Guidlines. - Maharashtra Pollution ...

contracts with change in humidity. This changes the capacitance which is sensed
electronically.
(iii) Technical Data
Measuring range : 10... 100% relative humidity
Accuracy : + 2% relative humidity
Length of scale : 94 mm
Graduation : 1% relative humidity
Load : Maximum 2 W
Slider current : Maximum 100 mA
Ambient temperature : -35... + 70 o C
Weight : 0.45 kg.
Models Available
Electrical outlet : Simple
Double
Measuring element : H
S (Hygrofix)
Type of connection : Lemosa plug
3 m cable
Electrical output : 40-50-40 ohms
50-30-50 ohms
0...100 ohms
50-150-50 ohms
0...200 ohms
0...1000 ohms
0...2000 ohms
0...200 ohms lin.
(iv) Installing the Instrument - Install the hygro-transmitter in such a way that it is
protected from jarring, dust, chemical impurities and splashing water. It can be
mounted with the aid of the R 3/4" nuts directly to the wall of the room where the
measurements are to be taken or can use the enclosed mounting angle to screw
it to a plane surface. Please make sure that the transmitter is in the correct
position for use - the immersion stem must be vertical and pointing downwards.
Should there be heavily polluted air or wind velocities above about 3 m/s, then it
will be necessary to employ a wind protection device in order to guarantee
accurate measurements. This device is simply slipped over the immersion stem
of the hygro-transmitter and turned so that the closed side faces the air stream.
Connect the electrical output of the hygro-transmitter to an appropriate display
instrument (see circuit diagram). If, the hygro-transmitter has a double outlet, the
second outlet can be used to connect a recorder or an additional display
instrument. If, the hygro-transmitter has a Lemosa plug connection, then we
recommend using a flexible pilot wire LiYY in the following models for the
electrical connection :
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