高精度多功能温湿度氧浓度测量仪

文中介绍集热敏电阻型温度传感器,高分子薄膜电容式湿度传感器,原电池型氧气传感器,以及高度集成化的专用芯片为后续电路,配以自行开发软件的智能化温湿度、氧浓度测量仪.该产品性能稳定、功耗低,价格低廉,具有精确数字显示温度、湿度、氧气浓度等功能.     

家用电器传感器讲座(六)

第四讲湿度与露点传感器(一)温度传感器在家电中的应用最近逐渐增多起来(表1),其广泛程度仅次于温度传感器。这是因为湿度与人的生活关系密切,例如房间空调,湿度过大过小都会使人感到不适。此外,在电子灶、干燥器和空调器中使用湿度传感器,均可获得显著的节能效果(30%～50%)。本讲着重介绍在家电中已获广泛应用的有机高分子湿敏元件和陶瓷湿度传感器。另外,对新开发出来的几种湿度传感器也将作简要介绍。     

基于单片机的多路数据采集与传输显示系统

以STC90C516单片机为主控制单元,采用数字温度传感器DS18B20作为温度传感器,采用数字温湿度传感器DHT11作为湿度传感器,采用液晶屏TFT2.4作为显示模块,设计了三路温度、两路湿度检测系统。给出了单片机单元、温度、湿度检测单元、LCD显示单元及辅助单元的硬件、软件设计方法。实验结果表明:该系统在-55~125℃测温,偏差小于0.5℃,能够显示实时时钟、时钟校准、闹铃等,具有可靠性高、体积小、携带方便、成本低、界面友好等特点,适用于大部分的温度、湿度数据采集。     

基于CAN总线的智能温湿度检测系统设计

设计的基于AT89S52的CAN总线系统智能节点,采用一线式数字温度传感器DS18820和电容式湿度传感器HS1101对现场温湿度进行采集,通过CAN总线接口实现工业现场温度和湿度的实时检测、远程传输和控制。     

威根德磁敏传感器

本文综述了威根德磁敏传感器的工作原理,制备方法以及主要应用。并对国内外的最新进展作了简述。     

新型场效应管型湿度传感器阵列的研制

以Baytron P为敏感材料,利用自组装技术在具有4个单元的无金属栅场效应管阵列上制备了Baytron P/PDDA多层自组装超薄膜,形成了一种以自组装膜取代MOSFET栅金属的化学场效应管型湿度传感器阵列,并对该阵列的湿敏特性进行了测试研究,同时设计了广义回归神经网络以进行湿度的预测分析.结果表明,采用1V漏电压下的漏电流值作为网络的输入,并取扩展常数为0.14时,网络的预测结果最好(最小相对误差为1.77%).     

基于双锥微钠光纤的GIS微水监测技术

GIS（气体绝缘封闭组合电器）内微水含量升高会降低其绝缘水平。为了实现对GIS内部绝缘气体湿度的在线监测,设计了一种基于双锥微纳光纤的GIS湿度传感器。首先采用BPM（光束传播法）对双锥微纳光纤的光场进行仿真,研究双锥微纳光纤的光场分布与模式干涉理论,得到SF6气体随微水含量的变化规律;然后采用熔融拉锥法制备了双锥微纳光纤湿度传感器,并进行了湿度传感实验。最后结合实验得出结论,基于双锥微纳光纤的湿度传感器检测灵敏度为-51.75 pm/%RH,能够实现对电气设备湿度的连续在线监测。     

基于PLC屋顶花园浇灌系统的设计与实现

为了实现植物生长所需的温度、湿度、光照等重要环境因素的自动调节,设计了一款基于西门子 PLC的自 动灌溉控制系统.该系统以组态王为上位机,PLC为下位机,通过组态与 PLC的通信,实时对花园动态情况的了解. 由液位传感器检测储水箱的水位信息进行抽水和放水,以土壤水分传感器、温度传感器采集的温湿度数据实现对屋顶 花园的适时灌溉.该系统具有手动和自动两种灌溉模式,操作简单、组态界面美观,能有效解决人们因工作繁忙、出 差等没有时间去浇灌这一难题.     

变压器油中微水含量在线监测的研究

分析了变压器中水分的分布状况以及油中水分的变化情况,提出了以相对饱和度和温度为监测特征量的变压器油中微水含量在线监测的方案。采用聚酰亚胺电容式湿度传感器和温度传感器实现对油中微水含量的在线监测,并利用计算机完成数据的采集与分析。在试验变压器上进行的实验表明传感器工作正常,能很好地反映变压器油中微水含量,达到在线监测的目的。     

变压器油中微水含量在线监测研究浅析

分析了变压器中水分的分布状况以及油中水分的变化情况,提出了以相对饱和度和温度为监测特征量的变压器油中微水含量在线监测的方案。采用聚酰亚胺电容式湿度传感器和温度传感器实现对油中微水含量的在线监测,并利用计算机完成数据的采集与分析。在试验变压器上进行的实验表明传感器工作正常,能很好地反映变压器油中微水含量,达到在线监测的目的。     

发电厂水汽系统溶解氧的在线测量

介绍扩散型和平衡型两种溶解氧测量传感器的测量原理,指出它们的共有测量误差来源及防止措施,并介绍了3种溶解氧测量仪的校正方法以及测量时的注意事项。     

集成温度传感器在测量系统中的应用

与热电偶、热电阻等传统温度传感器相比,基于硅PN结温度效应的集成温度传感器具有灵敏度高、线性较好、重复性好、尺寸小、响应速度快、直接输出数字信号,容易与测量电路系统接口等优点.本文介绍了集成温度传感器的性能参数以及与信号处理、外部设备一起构成的温度测控系统.     

Development of Corrosion‐Resistant Pressure Sensor with Semiconductor Strain Sensor

In automotive and industrial fields, pressure sensors are a key component for precisely controlling the mechanical systems. Conventional micro electro mechanical system (MEMS)‐based pressure sensors have an advantage in noise resistance, because both strain gauges and control circuits are integrated in one chip. However, the MEMS‐based pressure sensors are generally fabricated on an Si substrate, and have a low stability against various active gases. Thus, we have newly proposed a pressure sensor which consists of an Si‐based strain sensor set on a stainless steel diaphragm with a high stability against the active gases. The key technology is that a Koval plate is inserted between the strain sensor and the stainless steel diaphragm, for preventing the breakage or the delamination of the strain sensor at the bonding interface due to a difference in thermal expansion. Structure of the sensor including the shape and the size of Koval plate and the assembly position of the strain sensor were designed using structural simulation and experiments. Eventually, the 2.8 mm wide and 0.17 mm thick Koval beam was bridged on the stainless steel diaphragm for efficiently transmitting the diaphragm deformation to the strain sensor. The strain sensor was assembled at the edge of Koval beam with a glass bonding technique. Consequently, the developed pressure sensor has achieved a small dispersion of less than 1% F. S. in a temperature range from 0 °C to 85 °C.     

Ceramic Based Resistive Sensors

This paper reviews the current status and research trends of two types of ceramic based resistive sensors, thermistors and gas sensors. The issues and challenges associated with their development for high temperature applications are examined and discussed. Worldwide research efforts in ceramic based resistive sensors, devoted mostly to resolve the issues of selectivity and stability, are also reviewed. These efforts tend to integrate the results obtained from both empirical and basic science approaches, and focus on various stages of sensor development, including development of new material systems, sensor fabrication and manufacturing techniques, and smart sensor arrays.     

IR detectors using Pb(Mg1/3Nb2/3)O3 and Pb(Sc1/2Ta1/2)O3 ceramics under DC bias

Recently, one type of thermal-type IR detector, the pyroelectric sensor, has become of great interest in commercial applications, because of its ability to operate without cooling, its constant detectivity independent of wavelength, and its low cost. The conventional pyroelectric materials are usually normal ferroelectric materials with a first and second phase transition. The working temperatures are sufficiently below the Curie temperature T_c for stable responsivity to temperature. Electric field induced-type pyroelectric sensors have also been proposed. Relaxor ferroelectric materials such as Pb(Mg_1/3Nb_2/3)O₃ (PMN) and Pb(Sc_1/2Ta_1/2)O₃ (PST), which have a glassy Curie temperature near room temperature, are used in this type of sensor. This paper describes the sensor properties of electric field induced-type pyroelectric sensors prepared by using PMN and PST ceramics as compared with the conventional type sensors. Material evaluations of PMN and PST ceramics were made to determine their dielectric and pyroelectric properties. PMN shows excellent induced pyroelectric properties for the sensors over a wide range of temperatures. On the other hand, PST seems to be inadequate for an IR detector because of a very narrow high-response temperature range. The sensors with PMN and PST ceramics show enhanced pyroelectric activities under dc bias field. The measured sensor voltage responsivities agree with the calculated values for the PMN case. The electric field induced-type infrared sensor with thick or thin film materials seems to be satisfactory as linear array IR detectors for thermal imaging, with application of a higher electric field.     

温度传感器和流量传感器的结构与检修方法分析

传感器被越来越广泛的应用,其能否正常运行工作是研究的一个重要环节。水温表热敏电阻式传感器检查时,用万用表欧姆档测量传感器两端子间的电阻,电阻值的范围与冷却液温度传感器的相同。双金属片式气体温度传感器检修时,是将真空软管从电动机侧拆下,确认软管内无负压,然后当空气温度在17℃以下时,连接软管后,软管内应有负压,冷暖气转换阀升起为正常;当空气温度达到28℃以下时,软管内负压应减小。叶片式空气流量传感器检修时,用万用表欧姆档测量传感器各端子之间的电阻值,将其与规定的标准值进行比较后来判断传感器的技术状态。     

Poisoning of Temperature Independent Resistive Oxygen Sensors by Sulfur Dioxide

Sulfur dioxide strongly affects temperature independent resistive oxygen sensors of SrTi_1-xFe_xO_3-. Time dependent sensor deterioration was investigated for lanthanum doped SrTi_0.65Fe_0.35O_3- (STF35). Parameters were sulfur dioxide concentration, oxygen partial pressure, temperature, and sensor morphology. The sensor poisoning consists of two steps. At lower temperatures sulfur dioxide adsorption and sulfate ion formation at the grain surface is suggested. At higher temperatures the material decomposes into SrSO₄, iron depleted STF35, and Fe₂TiO₅.     

Influence of Water Vapor on the Response of Mg-Doped SrTio3 Ceramic Oxygen Sensors

Mg-doped SrTio₃ thick film sensors fabricated by screen-printing proved to be very promising for the use as oxygen sensors. A study of the influence of water on the response of these sensors gives an important basis for understanding their behavior in practical applications. The influence of water on the sensor response was measured in the oxygen partial pressure region from air (0.21 bar) to pure N₂ (2.5 × 10^–5)and the temperature range from 600 to 800°C. The relative humidity was varied from 1 to 95% RH. The resistance variation as a function of temperature and the activation energy were evaluated under different dry and wet conditions. The results obtained show that the resistance of these sensors generally decreases with increasing water content in the carrier gas and that the effect of water was strongest at lower temperatures as well as at lower oxygen pressures. To explain this behavior, it is proposed that a partial proton conduction is introduced in the water-containing atmospheres and that this contributes to the total conductivity leading to a reduction of the total resistance. Finally, the measurements also show that the response of these sensors still depends on the oxygen partial pressure according to the standard expression even in the presence of water vapor. Therefore, these sensors can still be used as oxygen sensors in humid atmospheres.     

现代传感器发展方向（续）

传感器是信息系统的源头,在某种程度上是决定系统特性和性能指标的关键部件。本文试图探讨现代传感器技术发展方向,从概念、原理、性能和应用等层面评述了9种传感器：光纤传感器、集成传感器、MEMS传感器、模糊传感器、智能传感器、多功能传感器、模型传感器、网络传感器及生物传感器,且每类传感器列举了应用实例。