Constant temperature and humidity aging test chamber humidity sensor 4 major con

Constant temperature and humidity aging test chamber using CNC machine tool processing molding, beautiful and novel shape and the use of non-reaction handle, easy to operate.

 

1, choose the measurement accuracy

 

Measurement accuracy is the most important indicator of the humidity sensor, each increase - a percentage point, the humidity sensor is a step up a grade. Because to achieve different accuracy, the manufacturing cost varies greatly, the selling price also varies greatly. Therefore, the buyer must be tailored, should not blindly pursue the "high, fine, sharp".

Such as the use of humidity sensors at different temperatures, the value should also consider the impact of temperature drift. Relative humidity is a function of temperature, the temperature seriously affects the relative humidity in the space. Every 0.1 ℃ change in temperature. Will produce 0.5% RH humidity change error. The use of the occasion if it is difficult to achieve constant temperature, it is not appropriate to propose too high accuracy of moisture measurement.

 

In most cases, if there is no accurate means of temperature control, or the measured space is non-sealed, ± 5% RH accuracy is sufficient. For the requirement of precise control of constant temperature and humidity of the local space, or the need to keep track of the humidity change of the occasion, and then use ± 3%RH above the accuracy of the humidity sensor.

 

And accuracy higher than ± 2% RH requirements, I am afraid that even the standard humidity generator to calibrate the sensor is difficult to do, not to mention the sensor itself. Relative humidity measurement instrument, even at 20-25 ℃, to achieve the accuracy of 2% RH is still very difficult. Usually the characteristics given in the product information are measured at room temperature (20℃±10℃) and in clean gas.

 

2、Select the measuring range

 

Select humidity sensor and weight, temperature, the same, the first to determine the measurement range. In addition to meteorology, scientific research departments, high temperature, humidity measurement and control of the general do not need the full wet range 0-100% RH measurement.

 

3, consider the time drift and temperature drift

 

In actual use, due to the impact of dust, oil and harmful gases, the use of time, electronic humidity transmitter will produce aging, precision decline, electronic humidity transmitter annual drift is generally in ± 2%, or even higher.

 

4、Other precautions

 

Humidity sensor is non-sealed, in order to protect the accuracy and stability of the measurement, should try to avoid the use in acidic, alkaline and organic solvent containing atmosphere. Also avoid the use in a dusty environment. To correctly reflect the humidity in the predicted space, you should also avoid placing the sensor too close to the wall, or in a dead end where there is no air circulation. If the room to be measured is too large, multiple sensors should be placed.

 

When the sensor needs to carry out long-distance signal transmission, pay attention to the signal attenuation problem. When the transmission distance exceeds 200m or more, it is recommended to use the frequency output signal humidity.

 

Some humidity sensors have high requirements for power supply, otherwise it will affect the measurement accuracy. Or the sensors interfere with each other, or even can not work. Use should be in accordance with technical requirements to provide a suitable, in line with the accuracy requirements of the power supply.

 

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