8
3.5 Measurements using optional probes
(Temperature & Humidity, Air velocity)
◆
Air velocity probe
＊
When measuring, set wind direction mark against the wind direction.
＊
Check the tip of probe periodically to confirm that it is kept clean.
Dust attached to the sensor will affect the accuracy of the measurement.
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Cleaning of the air velocity probe
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◆
Temperature & Humidity probe
＊
As for measurements of air temperature, accurate value will not be given in the still air.
(Exempt from performance-guarantee range.)
You can get correct value in velocity of 0.1m/s or over. (Move probe slowly.)
＊
Response time in the air temperature measurement becomes quicker when the velocity is high.
For example, when air velocity is 1m/s the response time is 20 seconds. Please keep the data when
indications become stabile.
＊
The humidity measurement value might rise abnormally by the condensation of the humidity sensor.
In case of the measurement in rapid temperature change or long use in high humidity, keep probe for 24 hrs
in 40%RH or less and dry probe when wet.
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Humidity measurement … Comparison with ASSUMANN type psychrometer
―
Wind
Wind direction mark
◇
Rinse tip of probe in alcohol if sensor is oily, dry it in low wind.
◇
When you get rid of dust, blow them off by blow blush for camera or rinse in water and dry them
completely.
※
Turn off power when you wash sensor.
※
Do not dry probe with heat.
（
Heat damages sensor and became impossible to restore. )
Because the humidity measurement function is strictly proofread using
a standard humidity generation
device (two temperature difference method), you will find it is handy.
And, because a steady measurement can be done as an electronic hygrometer, this unit can take the place
of ASSUMANN type psychrometer.
When the comparison measurement is done between T/H probe and the ASSUMANN type psychrometer,
the ASSUMANN type psychrometer occasionally display high humidity.
Since handling conditions like dust, dew, or how to lap gaze can in flvence the result of ASSUMANN.
Therefore, it is necessary to be careful when you handle the ASSUMANN type psychrometer.
Please refer to Japan Industrial Standards concerning notice in the measurement with the ASSUMANN type
psychrometer etc. (JIS-Z8806 "Method of measuring humidity") etc.