ADuC845单片机和PFR2000的无线数据采集系统设计

设计了一种基于单片机ADuC845和PTR2000的无线数据采集系统,该系统充分利用ADuC845单片机的片上资源,特别是两个多通道且皆可达到24位分辨率的A／D转换器。它对外部模拟信号温度、湿度、压力通过传感器进行输入、放大、滤波后送入A／D转换器。通过对寄存器的合理配置,得到稳定的输出值,在数码上显示输出。最终通过PTR2000将处理后的数据发送到PC机上。     

The origin of melt-texture crystal growth process in a simple tube furnace

The melt-texture growth (MTG) method has been shown to be effective in fabricating high-T _csuperconducting bulk samples with highly oriented layers of single crystals. The critical current densityJ _cof the typical samples are enhanced significantly. Furthermore, making use of the nonzero spatial temperature gradient at certain locations of a common tube furnace, we fabricated Y-123 bulk samples with various dopants allowingJ _cup to 3.0×10⁴ A cm^–2 in our recent investigations. We followed up our project by analyzing the relations among the crucial parameters involved in the modified version of the MTG process. These parameters include the temperature gradient, the time rate of change of temperature, the growth front of the crystal, etc. Our study indicates that some of the empty space regions that appear between layers are only shallow gap lines. True layers of single crystals do exist, and we present an explanation for the growth of crystal layers along special directions as observed.     

Hybrid Control Strategy for Thermal Cycling of PCR Based on a Microcomputer

Abstract

In the polymerase chain reaction (PCR), the reference temperature profiles of thermal cycling must be tracked rapidly and precisely so as to amplify DNA in samples, strictly following the exponential function of 2ⁿ (n: thermal cycles) as quickly as possible. For this purpose, a model based hybrid controller to follow up setpoint changes is developed which is easily implemented with a microcomputer ADuC834 for its simple configuration and low cost of computation. The hybrid control strategy combines feedforward, feedback, and Bang‐Bang actions to achieve better setpoint response and steady state behavior. Based on the steady state model of the thermocycler, the feedforward action serves as the model predictive control for each setpoint, while the feedback controller is used as the local control action to accelerate ramp rates and reduce the tracking errors. The model of the thermocycler is identified with step response data at different operation regions. Experimental results demonstrate that, besides the improvement of the tracking accuracy, both the rise time and the decay time of each thermal cycle have been reduced significantly with the hybrid control strategy, compared with the conventional PID. Therefore, improved efficiency and accuracy of the polymerase chain reaction is achieved.     

数据采集系统芯片ADuC812及其在温度监测系统中的应用

使用通常的单片机、A／D转换器等芯片构造一个数据采集系统,往往设计周期长,成本较高。ADuC812采用了高性能的闪速／电擦除存储器技术和模拟测量技术,能灵活地对芯片进行编辑,同时更方便地解决了数据采集问题,并大大降低了数据采集系统的开发时间和成本。本文详细介绍了ADuC812的性能、特点,并给出了在温度监测系统中应用的实例。     

基于ADμC812温度补偿系统的压力变送器

基于ADμC812微处理器,建立了稳压补偿数学模型,从而使压力随温度的变化呈线性关系。测试结果表明,用一种软件数据处理算法代替传统的硬件补偿校正电路,具有输出线性良好、节省成本的优点,同时,整个系统具有结构简单、操作简单、输出精度高的优点;静态输出电流精度控制在5‰以内,达到国家统一仪表准确度一级标准。该种数学模型的建立方法可适用于声学系统的超声波传感器的数据拟合,实现超声波传感器在不同的应用环境下满足测距及其他测量的测量精度。     

基于ADuC841的无线收发系统

本文介绍了以ADuC841,结合CC1000无线收发模块设计的一套无线收发系统。ADuC841采集已知的测试信号,通过CC1000把数据发送给接收端;接收端接收信号,并将数据经串口传送给PC,通过串口调试助手显示信号数据,从而验证系统数据的发送和接收是否准确。3个模块之间的数据传递通过SPI进行。该系统主要特点是采用内部集成高精度ADC的ADuC841作为主控芯片,其集成度高,简化了系统结构和电路的设计,便于今后电路的扩展和无线数据的传输,具有较高的工程应用价值。     

AduC812内部资源的使用及C语言编程方法

充分利用芯片内部的资源将简化系统设计与编程。本文以AduC812与外围设备X5045通讯为例，详尽介绍了AduC812串行外设接口(SPI)的使用方法，并且以实例指出了如何对芯片内部的电源监视器进行控制编程。     

蓄电池在线智能监测仪的设计

蓄电池作为电力系统的后备电源，其维护工作对保证电力系统的安全运行具有重要意义。对蓄电池实施在线监测并及时发现失效电池，是蓄电池维护工作的重中之重。文中介绍一种以单片机ADuC831为核心的新型蓄电池在线智能监测仪，能实现对蓄电池无论在浮充状态还是充、放电动态过程中的状态检测。着重介绍其软硬件设计方法。     

ADuC812在三相电能测量系统中的应用

介绍了数据采集系统芯片ADuC812的特点，并给出了用该芯片实现三相电能测量系统的设计。该电能测量系统具有成本低、功能强、功耗低等特点。