Some Problems in Selecting Temperature Sensor
Human survival and social activities are closely related to humidity. With the realization of modernization, it is difficult to find a field that has nothing to do with humidity. Due to the different application areas, the technical requirements for Temperature Sensor are also different. From the manufacturing point of view, with the humidity sensor, materials, different structure, different processes. Its performance and technical indicators are very different, so the price is also very different. For the user, the choice of humidity sensor, the first to figure out what kind of sensor; their own financial resources to allow what grade to buy products, trade-off "need and possible" relationship, not blindly act. We from the user's contacts, that the following questions worthy of attention.
1. Select the measuring range
And measuring the weight, temperature, select the humidity sensor first to determine the measurement range. In addition to weather, scientific research departments, engage in temperature and humidity monitoring and control generally do not need full wet (0-100% RH) measurement. In today's information age, sensor technology is closely integrated with computer technology and automatic control. The purpose of the measurement is to control, the measurement range and the control range are collectively used. Of course, do not need to engage in measurement and control system for the application, the direct choice of universal humidity instrument on it. Here are some of the application areas of the humidity sensor temperature and humidity requirements for different users (see Table 1). The user according to the need to the sensor production plant to measure the scope of the production plant priority to ensure that users within the scope of the use of consistent performance of the sensor to obtain a reasonable price performance, the two sides is a mutually beneficial thing.
2, select the measurement accuracy
As with the measurement range, the measurement accuracy is the most important indicator of the sensor. Every increase - a percentage point. On the sensor is a step, or even a grade. Because to achieve different precision, its manufacturing costs vary widely, the price is also very different. For example, the import of an inexpensive humidity sensor is only a few dollars, and one for the calibration of the whole wet humidity sensor to hundreds of dollars, a difference of nearly a hundred times. So the user must be tailored, should not blindly pursue the "high, refined, sharp."
The manufacturer is often given the accuracy of the humidity sensor. (± 80% RH) is ± 2% RH, and the high humidity section (80-100% RH) is ± 4% RH. And this accuracy is at a given temperature (eg 25 ° C). Such as the use of Temperature Sensor at different temperatures. The value of the temperature drift should also consider the impact. As we all know, relative humidity is a function of temperature, the temperature seriously affects the relative humidity within the specified space. The temperature varies by 0.1 ° C. Will produce a humidity change (error) of 0.5% RH. If the use of occasions if it is difficult to achieve constant temperature, it is not appropriate to put too high humidity accuracy. Because the humidity changes with the temperature is also drastic, then talk about measuring wetness will lose practical significance. So control the wet first to control the temperature, which is a large number of applications is often the temperature and humidity - the sensor rather than simply the humidity sensor.