Subway environmental control systems widely used in temperature and humidity sensor

Metro has become an essential transportation in big cities run the tool , it has a large volume, punctuality is good, fast and safe , transport , high efficiency, environmentally friendly advantages. As subway passenger trips and more, how to give passengers a comfortable thermal environment satisfactory , becoming the transport sector needs to be considered and resolved. This requires careful design of the subway environmental control system in which temperature and humidity sensor detection tool is required . Metro 's large volume, which is a large passenger flow , the required variation in fresh air . Therefore subway air conditioning load changes, to achieve energy must resort to automatic control means. Automatic control system as an integral part of , environmental sensors in the subway more plays an important role . The environmental control system in the subway , the main use of the indoor Automobile Temperature Sensor and humidity sensor , duct temperature and humidity sensors . We can order at the station concourse and platform areas and other public areas as well as important equipment room set indoor temperature and Crank Position Sensors to monitor real-time temperature and humidity of the station . These parameters can help operational staff working conditions of various systems of the station to make reasonable adjustments to keep always in the public areas of the station more comfortable environment to ensure that the device has been in the right room temperature under . Indoor temperature and humidity sensors are generally mounted on the station concourse , platform and equipment room on the wall or on top . In the meantime, we can at the station 's new air chamber and the return air duct temperature and humidity chamber Engine Coolant Temp Sensor to monitor the outdoor air and the temperature and humidity inside the station . Environmental control system according to the data collected by sensors to determine the environmental quality of the station , and according to a variety of conditions pre-designed for automatic switch , automatic control system in order to achieve automatic control of the environment of the station , so that the station is always in a more environment comfortable environment, and ultimately achieve the purpose of energy saving and emission reduction . Pipeline temperature and humidity sensor is usually installed in the new and the return air plenum chamber walls. Thus, the temperature Crankshaft Positioning Sensor usefulness in life more and more, it is not only in the station , greenhouse , file management and food industry has applied , is now in the subway environmental control system has also been adopted .

Piezoelectric ceramic ultrasonic sensor working principle and structural characteristics

Ultrasonic sensors are developed from the use of ultrasonic sensor characteristics , because of its reliable, easy to install, waterproof , launch angle is small, high sensitivity , are widely used in liquid level monitoring, robot collision avoidance , a variety of ultrasonic proximity switches, and burglar alarm and other related fields. As we all know , is the production of piezoelectric ceramic Automobile Temperature Sensor probes commonly used materials . Here's a look at piezoelectric ceramic ultrasonic sensor working principle and structural characteristics . When a voltage is applied to the piezoelectric ceramics , piezoelectric ceramics will change with voltage and frequency mechanical deformation . On the other hand , when the vibration of piezoelectric ceramics , an electrical charge is generated . Using this principle , when given by the two piezoelectric ceramic or a piezoelectric ceramic and a metal sheet having a vibrator, the bimorph element , applying an electrical signal , it will emit an ultrasonic vibration by bending . In contrast, when applied to the bimorph element ultrasonic vibration , it will generate an electrical signal. Because of these effects , it can be used as a piezoelectric ceramic Crank Position Sensor . The ultrasonic sensor is a composite vibrator be flexibly fixed on the base . The compound of the resonator and the vibrator consists of a metal plate and a piezoelectric ceramic bimorph element consisting of a combination of the vibrator . Resonator flared aims to effectively radiate ultrasonic waves generated due to vibration , and the ultrasonic waves can be effectively central portion of the vibrator . Piezoelectric ceramic ultrasonic sensor uses a point to note is that in the high- frequency probe , you must use the vertical thickness vibration mode piezoelectric ceramic . In this case , the acoustic impedance of piezoelectric ceramic matches with the air becomes very important . Because the acoustic impedance of the piezoelectric ceramic 105 acoustic impedance of air , which will cause the vibration of the piezoelectric ceramic significant loss of radiation on the surface , then you will need to adhere to a special material on the piezoelectric ceramic Crankshaft Positioning Sensor , as acoustic matching layer , the air can be realized with acoustic impedance matched , so as to achieve the purpose of the measurement .

The method of the pressure sensor What impact

Pressure Sensors impact one way to do ? Pressure sensors used in many environments, some relatively poor environment , we generally have the following several ways to measure . The first method is to change the pressure transmitter chip , not an ordinary ceramic cores or diffused silicon core , but with strain gages , strain gauges is a strain on the DUT will be converted into an electrical signal of change sensitive device. It is a piezoresistive Cooling Temp Sensor of the main components . Resistance strain gauge is the most widely used metal resistance strain gauges and semiconductor strain gauges two kinds . Metal resistance strain gauges have filamentous strain gauge and the metal foil strain gages two kinds . The strain gauge is usually via a special adhesive binder tight mechanical strain is generated on the substrate , the force occurs when the substrate stress , the resistance strain gauge is generated with deformation, the resistance strain gauge is changed , so that the the voltage across the resistor changes . The strain gauge force generated when the change in resistance is usually small , it typically are composed of strain gage bridge , and through subsequent instrumentation amplifier is amplified , and then transmitted to the processing circuit . Strain gauge Crank Position Sensoris generally shock and impact resistance is better, but this sensor accuracy with their manufacturers . The second method is to use an ordinary ceramic Shaft Position Sensor or pressure sensor to measure diffusion silicon , but not be measured directly , but with the addition of a buffer tube , which also can measure the impact pressure . This method is economical , easy to install , so the application is very extensive. Regardless of the method is to measure the impact pressure sensor core body protection is not strong pressure washed out . Which method based on the specific use now have a bad environment and customer choice .

How to improve sensor performance

Sensors in the Chinese market, account for a large proportion of China's development has played a very important role , how to improve the performance of the sensor does , the problem to be studied , the following is to introduce you to . First, make a reasonable choice of materials and design Crankshaft Position Sensor selection of materials and structural design aim is to ensure that key indicators , secondary indicators required to give up , so cost-effective, while meeting the needs of measurement , do not blindly pursue high targets . Second, the average effect of using the average technical error and data averaging is typical application example , a common practice programs and how many times the sampling point measurements mean . Third, the use of differential technology can not only reduce the nonlinear differential technique , but also increase the sensitivity , offset the common-mode error . Differential technique commonly used in strain gauge , inductive and Auto Temperature Sensor . Fourth, compensation and correction techniques which not only through the use of electronic technology circuit ( hardware ) to solve, can also be used microcomputer via software. Fifth, in order to improve the stability ofCooling Temperature Sensor processing performance stability , should produce materials, components , and sensors necessary stability whole process . If the measurement higher, if necessary, also the need for an additional adjusting element , the key components of the circuit followed by the aging process . Six, shielding, isolation and interference suppression this method is mainly to weaken or eliminate the influence of external factors , and grounding or shielding of the sensor away from the power cable or the output wire shielded , twisted twisted together so the output line shielding, isolation , You can also filter and other methods can be used to suppress .

Temperature sensor

Automotive Temperature sensors are used to detect the engine temperature , suction gas temperature , cooling water temperature, fuel temperature and the catalyst temperature. Temperature sensor thermistor , RTD and thermocouple wire wound resistive three main types . These three types of sensors have their own characteristics , and its applications are also slightly different. Thermistor temperature sensor with high sensitivity , response is good, but poor linearity , adapt to the temperature is lower. Among them, the general-purpose temperature range of -50 ℃ ~ 30 ℃, accuracy of 1.5% , a response time of 10 ms; high temperature of 600 ℃ ~ 1000 ℃, accuracy of 5% , the response time is 10ms; wirewound resistive Camshaft Sensor accuracy is high, but the response characteristic difference ; thermocouple Engine Temperature Sensorsresistance , high precision measurement temperature range , but require treatment with the cold end amplifier together. Other practical products ferrite temperature sensor ( temperature range is -40 ℃ ~ 120 ℃, accuracy of 2.0% ) , metal or semiconductor film air Crankshaft Positioning Sensor ( temperature range is -40 ℃ ~ 150 ℃, Accuracy of 2.0 %, 5% , the response time of about 20 ms) and so on.

Non- contact temperature sensor

It can be used to measure the movement of objects , a small thermal capacity , a very rapid temperature change or a small target temperature of the surface of the object , but also can be used to measure the temperature distribution of the temperature inside . Measured object is saying there is no contact between the sensing element , so it also called non- contact Thermometer . Now the most frequently used non- contact Shaft Position Sensoris based on the basic law of blackbody radiation work , known as the radiation thermometer tables. Radiation thermometry method has the following categories: colorimetric , radiation and brightness of the Act . The above method can only measure the temperature of the corresponding colorimetric , photometric radiation temperature and temperature . However, only about blackbody temperature measurement is the real temperature.Non-contact temperature Crank Shaft Sensor measuring temperature main advantages : For temperatures above 1800 ℃ , generally using a non- contact temperature measurement method ; its measurement limit is not affected by temperature sensing element temperature limits the degree of Therefore the highest Car Temperature Sensor for the measurement , in principle, is not also limited ; infrared technology is now becoming more and more well, and the radiation temperature gradually from the visible to the infrared to expand , until room temperature is lower than 700 ℃ of which can be measured , and and its resolution is very high.

Contact temperature sensor

As part of this Cooling Temp Sensor between the measured object with a good contact, so again it is usually called a thermometer. It is by conduction or convection and thermal equilibrium state , it can be directly displayed value represents the case of the measured temperature of the object . Generally, it 's measurement accuracy is relatively high . Within a certain temperature , it is even able to measure the temperature inside the object of each case . However, if the measurement is the movement of objects , the heat capacity of small objects or small target, the measurement results will have a relatively large errors , frequent use of the thermometer with pressure thermometer , resistance thermometers , bimetal thermometers and glass liquid thermometers, etc.Crankshaft Positioning Sensor. They are in the commercial, agricultural and industrial applications are very wide , even in normal life , people often use these thermometers. In electronics, medicine, metallurgy , defense engineering and food sectors , cryogenic technology is widely applied , and there are strong research on superconducting technology , and now you want to measure the temperature of the low temperature below 120K thermometer has been well development , such as : acoustic thermometer, temperature heat thermometer , vapor pressure thermometer, gas thermometer and temperature and so on. Low temperature thermometer element to smaller size , better stability and reproducibility and accuracy is higher. Carburizing heat resistive glass using a porous sintered high-silica glass to form a low temperature carburization thermometer in one temperature sensing element , which can be used to measure 1.6 ~ 300K temperature within this temperature range .