Design of Laser Radar Fiber Optic Liquid Level Sensor System

A novel fiber optic liquid level sensor based on laser radar (ladar) is reported here. Using the perfect technique of ladar in which the phase of amplitude modulated light wave reflected from the liquid surface is compared with that of original modulation signal, the distance can be measured precisely. A special symmetric compensating coaxial optical system is proposed to eliminate many adverse effects. It realized the one-time electronic-free optical measurement on a simulated oil tank and achieves an accuracy of 0.3%, within a temperature range of -10 ℃～+40 ℃ over a measuring of 0～10 m.

New Measuring Method for Colorless Liquid Level Based on CLC100 Level Sensor and Powercast Wireless Sensor Kit

In this paper, a new wireless measuring method for colorless liquid level measurement was presented, based on latest CLC100 liquid level sensor and Powercast wireless sensor development kit. The wireless system is divided into two parts, level measurement and data transmission part as well as data receiving and display part. First part included the capacitive liquid level sensor CLC100 and the wireless senor board. CLC100 sensor was used for liquid level measurement. Wireless sensor kit from Powercast Corporation included one wireless sensor board, which was used for signal transmission. A built-in PIC microcontroller was embedded in the transmission module, for the purpose of processing and data transmitting. Due to CLC100 sensor’s output voltage exceeding the sensor board’s input limitation, a voltage convertor was designed to connect the sensor and the wireless sensor board. The final results were voltages corresponding to the liquid level, and were processed by an independent PIC development board, and then sent to PC’s hyper terminal via serial-port by this PIC microcontroller. Experiments showed that this wireless sensor node prototype worked well.

The Design Liquid-level Monitoring System of Adopting the Ultrasonic Sensing Technology

Utilizing the technology of Ultrasonic wave,relevant test arithmetic and the PC to carry on monitoring,controlling and cen-tralized management of the liquid-level in the liquid container. It can prevent from keeping in touch with the examined liquid,not only has increased the continuous working time of the system greatly,simplifying maintenance of the sensor conveniently,can also realize overhauling in producing and boost the productivity and management level. The working principle,hardware structure of the instrument and the design method are presented,and the selection of sensor and MCU is discussed in detail in this paper. MCU are used to control the emission and receiving. Then the liquid-level are calculated,which makes the design more intelligent.

基于单片机的造纸用液位自动化控制系统研究

为切实应对以往造纸用液位控制系统依赖于自动控制机理构建控制电路所造成的液位控制精确度低与自动化程度低等问题,由嵌入式技术重焕液位控制系统活力着手,针对造纸碱回收蒸发工段黑液液位控制需求,基于52单片机和超声波传感器搭建了液位自动化控制系统。系统测试结果表明,以单片机与传感器相结合的液位控制系统精准度高、自动化程度高,且安全稳定性更高,不仅可充分适应当前追求无人化、高效化的造纸工业生产体系,还可普遍推广应用于其他工业领域。

基于离散马尔可夫模型的液位感测系统分析

阐述一种新的测量原理及测量电容结构,其利用模型计算传统式电容液位测量方法中测量介质介电常数数据,分析定期标定的原因。新系统根据液位变化、介电常数、电容量关系,实现高精度测量。

基于FDC2214的非接触式液位检测系统的设计

为解决有腐蚀性、易气化、易固化等特殊液体液位测量的问题,提出了一种基于FDC2214电容式传感器的非接触式液位测量系统。设计了由STM32F103主控芯片、FDC2214电容传感器等组成的非接触式液位测量硬件系统,通过对电容值变化量与温度的变化曲线进行数据分析,搭建了对应的温度补偿系统。此外,系统采用卡尔曼滤波算法对测量数据进行滤波处理,有效地提高了系统的测量精度和稳定性。实验测试结果表明:液位测量系统对10组不同的液位进行测量,液位计灵敏度为190.5 pF/m;液位测量系统可以在不改变液体容器结构的情况下完成液位测量;卡尔曼滤波算法可以有效提高液位计的测量精度和稳定性。

准确检测液位的光纤Bragg光栅弹性膜片传感器

为了准确测量液位,研制了一种耦合光纤布喇格光栅和弹性膜片的液位传感器。该传感器由两个光纤光栅(FBG_1和FBG_2)、弹性膜片、弹性橡胶密封垫片、空心管(导气管)和光纤光栅固定装置组成。光纤光栅固定装置材料为聚甲基丙烯酸甲酯。FBG_1和FBG_2固定在弹性膜片表面。FBG_1用于监测液位高度和温度。将FBG_2封装在不锈钢毛细管中进行温度检测,消除液相温度变化对液位测量的负面影响。为了提高传感器检测液位的线性度,实验研究了弹性膜片厚度对液位测量结果的影响,并在此基础上研究了液位变化率和外部振动对液位测量精度的影响。结果表明,当弹性膜片厚度为2 mm时,传感器检测液位的线性范围为0~380 cm,灵敏度为(19.65±6.3)pm/cm。该传感器可在0~100 cm/min液位变化速率和0~5.27 mm/s外部振动强度范围内准确监测液位,最大检测误差为7.2%。

基于微波原理的高精度液位传感器

本文提出并演示了一种基于微波谐振原理的带有电阻消能结构的高精度液位传感器,在0~50 mm的量程范围内,分辨率可达微米级。微波谐振原理传感器第一反射点是传感器自带的固定点,第二反射点为液面,即为可变点,两反射点之间形成谐振腔结构。当液面的高度发生变化时,第二反射点发生移动,会导致两个反射点之间的距离发生变化,因此改变谐振腔长,通过测量谐振腔长的大小即可确定液位的变化量。同时,所加入的电阻在提高量程范围的基础上,还大幅提升了频谱质量和测量精度。实验结果表明,该液位传感器在0~50 mm的量程范围内具有1μm数量级的分辨率和-1.927 2 mm/mm(谐振波长变化/液位)的灵敏度。该新型微波液位传感器具有机械鲁棒性强、易于制造、成本低和高分辨率等优点,有望应用于水利水电的量水堰监测等领域。

Fully self-powered instantaneous wireless liquid level sensor system based on triboelectric nanogenerator

Self-powered sensors are highly sought for wireless sensing applications in space exploration,industries,and environmental monitoring,etc.However,most current self-powered sensor technologies are based on the multiple energy conversion routine:energy collection,rectification,energy storage,and power management before it can be used for sensor systems,leading to exceptionally low energy utilization efficiency and very short periods of wireless sensing operation with majority of information lost.Here,we propose a triboelectric nanogenerator(TENG)based fully self-powered instantaneous and real-time wireless sensor system which does not contain electronic devices and microchips,but the passive components only.An innovative cylindrical capacitive-type liquid level sensor is also proposed and is then integrated into the wireless sensor system for monitoring liquid levels or identifying substance of the liquids.This sensor system can convert pulsed voltage output of the TENG into sinusoidal signal with a resonant frequency containing the sensing information and is transmitted to the receiver in distance in real-time.The maximum transmission distance of the sensor system could reach 1.5 m for a 10 cm diameter magnetic-core coil pair.The wireless sensor system exhibited excellent stability and excellent linearity with a sensitivity of 4.63 kHz/cm,and demonstrated its great application potential for the self-powered liquid level monitoring.

双闭环比值控制系统传感器故障诊断方法

双闭环比值控制系统由于主从回路滞后效应和闭环回路调节作用,使其故障诊断较为复杂。针对该系统传感器故障难以识别的问题,通过分析反映系统动态特性的实时数据,提出一种基于数据驱动的故障诊断方法。利用拉伊达准则标定检测阈值建立故障检测模型;利用传感器故障传播的滞后特性建立故障定位模型;利用突变故障的幅值特性建立了故障估计模型;利用故障调节动态过程的变化趋势建立了故障分离模型;通过在线数据标定获得了故障诊断动态模型。通过实验验证该方法的有效性和高精度。研究结果表明,所提方法适用于一般双闭环比值控制系统传感器的实时故障诊断,其中故障检测准确率可达98.5%,故障定位准确率可达98.5%,故障估计准确率可达99.28%,故障分离准确率可达98%。

Ultrasensitive liquid level sensor based on slice-shaped composite long period fiber grating

In this paper,a novel liquid level sensor with ultra-high sensitivity is proposed.The proposed sensor is configured by a sliceshaped composite long period fiber grating(SSC-LPFG).The SSC-LPFG is prepared by polishing two opposite sides of a composite multimode-single-mode-multimode fiber structure using a CO;laser.The method improves the sensitivity of the sensor to external environment.Based on the simulation calculation,a liquid level sensor with a length of 3 mm is designed.The experimental transmission spectrum agrees well with the simulation result.The experimental results show that the sensitivity reaches 7080 pm/mm in the liquid level range of 0-1400 μm in water.The temperature sensitivity is24.52 pm/℃ in the range of 20℃-90℃.Due to the ultra-high sensitivity,good linearity,and compact structure,the SSC-LPFG has potential application in the field of high-Drecision liquid level measurement.

C8051F020在磁致伸缩液位传感器中的应用

本文采用美国 Cygnal公司最新推出的 C80 5 1F0 2 0单片机 ,利用其速度快、功耗低、运算处理能力强以及有高速信号捕捉功能等特点 。

磁致伸缩液位传感器机理研究

详细介绍磁致伸缩原理,深入分析磁致伸缩原理在位移和液位检测中的具体应用,重点讨论磁致伸缩液位传感器的总体结构、波导管的结构、材料的选择以及回波接收的原理并给出了接收装置的方案,分析时间检测原理和方法,提出实现高精度测量传感器的温度补偿和抗干扰措施。通过以上机理分析对传感器的设计和应用提供理论指导。

磁致伸缩液位传感器检测信号影响因素分析及实验研究

磁致伸缩液位传感器作为液位测量装置,其检测信号对磁致伸缩液位传感器性能产生直接的影响,因此检测信号影响因素分析对优化传感器的性能至关重要。本文从检测线圈结构和脉冲电流参数对检测信号的影响进行讨论,建立了基于检测线圈的等效电路模型,使得在确立线圈结构参数时有了理论依据;观察检测信号波形变化趋势,得到感应信号随影响因素的变化曲线,从而得出液位传感器最优参数。优化后的液位传感器,提高了检测信号的抗干扰能力及其稳定性。该研究结果为磁致伸缩液位传感器的优化设计提供理论基础与指导。

新型液位检测技术的现状与发展趋势

文章介绍了工业生产过程中采用的光纤液位计、磁致伸缩液位计、音叉液位限位开关、差压式液位计、雷达液位计、伺服型浮子液位计等几种较新的液位检测仪表及其检测方法,并对几种液位计的特点进行了分析比较。文章最后指出,液位自动检测技术一方面需采用新的测量原理,开发新的液位检测仪表,扩大检测的手段,另一方面需朝着微机化和智能化方向发展。

电容式液位测量系统的设计

电容式液位测量系统是基于改变介电常数时,电容器的电容量变化的原理来测量液位的。利用电容式传感器,ADC0809,8031,2764,8155单片机和LED数码管等组成测量系统,对煤油的液位进行测量。它具有设定液位、显示当前液位和声光报警的功能。实验表明:该系统能对导电液体的液位测量,并具有结构简单、成本低、性能稳定等优点。

光电液位传感器及其在桥梁挠度自动测量中的应用

挠度是反映桥梁线性变化的重要参数,光电液位传感器是一种新型的连通管液位检测传感器,它的测量精度能达到0.1mm。将光电液位传感器、连通管、485总线、RS485/232转换卡、计算机等组成桥梁挠度自动测量系统,能够对大型桥梁挠度进行多点、长期、在线、远程、自动监测且不受桥梁现场高尘、高湿和浓雾的影响。目前,该系统已经成功应用到重庆大佛寺长江大桥上,测量结果表明可以准确获取桥梁的挠度信息,测量的挠度值能够真实反映桥梁的挠度变化,是一种有效的桥梁挠度自动测量方法。

基于错位和花生形结构的全光纤马赫-曾德干涉仪的研究

研究了一种基于错位和花生形结构的全光纤马赫-曾德干涉仪,进行了液位和曲率的测量实验,利用错位结构将纤芯模式激发到包层,包层模式经过花生形结构被耦合到纤芯与原有的纤芯模式发生干涉。包层模式对外界物理量如折射率、应力的变化敏感,导致透射光谱漂移。波谷波长的漂移量与液位和曲率的变化成线性关系,利用波谷的漂移实现液位和曲率的测量。在液位实验中,在水位变化范围为1.00~5.00cm时,波谷向短波方向漂移,灵敏度最高为-0.68nm·cm^(-1),线性拟合度为0.995 4。在曲率实验中,曲率的变化范围为0.3~1.2 m^(-1)时,波谷向长波方向漂移,灵敏度最高为22.47nm·m,线性拟合度为0.986 4,表现出较高的灵敏度。错位结构和花生形结构被用于组成马赫-曾德干涉仪,用普通的光纤熔接机和普通单模光纤即可熔接,结构和制作方法简单,灵敏度高,尤其在曲率的测量中表现出较高的灵敏度。

基于单片机和LabVIEW的远程矿井水位监控系统设计

针对现有矿井水位监控系统存在结构复杂和不能远程监控的问题,设计了基于单片机和LabVIEW的远程矿井水位监控系统,详细介绍了系统的硬件组成、上位机通信和下位机软件设计。该系统在现场利用单片机对水位进行监控并控制水泵,采用LabVIEW对水位进行监视并将水位信息存储在数据库中,实现了对矿井水位的远程监控。

磁致伸缩液位传感器的应用与发展

磁致伸缩液位传感器是综合利用磁致伸缩效应、浮力原理、电磁感应、电子技术等多种技术研制而成的液位测量仪表,它在高精度液位测量领域中相对于传统液位传感器有许多独特的优势。本文分析了磁致伸缩液位传感器的工作原理,阐述了其结构和使用特点,介绍了工业中几种常见的磁致伸缩液位传感器,并对磁致伸缩液位传感器未来的发展趋势作了探讨。