为了解决磁放大器性能测试过程中，需要对其供给不同数值恒定电流的问题，设计了一种基于DAC7512和单片机的数控恒流源系统。该系统采用AT89C51作为主控器件，将计算机发送的电流控制字命令转换为D/A转换器控制字，通过模拟SPI通信接口，写D/A控制字到DAC7512，从而控制其输出相应数字电压值，经差动缩放电路、电压/电路变换电路和功率驱动电路，最后输出恒定电流。实验结果表明，恒流源输出电流调节范围为-45~+45 mA、精度为±0.1 mA，分辨率达0.024 4 mA，具有应用灵活，外围电路简单，可靠性高的特点。该数控直流恒流源也可为相关产品的测试系统研发提供参考。 Abstract: In order to solve the need to supply different values constant current for the magnetic amplifier in testing process， numerical control constant current source system was designed based on DAC7512 chip and microcontroller technology. The system used the AT89C51 as the main chip， which can convert the current control word from computer into to D/A control words. And the system wrote D/A control word into the DAC7512 chip to control the output voltage value by the SPI communication interface， which can output corresponding constant current figures by scaling circuit， the V/I converter and power drive circuit. Experimental results show that the current source output current adjustment range is -45~+45mA， accuracy is ± 0.1mA， and resolution ratio is 0.024 4mA
上传时间： 2014-12-27
上传用户：invtnewer
提出了一种基于C8051F320的列车安全巡检仪的设计方案，详细阐述了巡检仪的各个模块的硬、软件设计。巡检仪集信息采集、轴温检测、照明和记录存储等功能于一体，实现了对列车安全巡检工作有效的监督和科学管理。系统软件采用C51编写，对单片机进行有效的电源管理，保证了巡检仪的稳定性、可靠性和低功耗性。 Abstract: This paper puts forward a design of train safety inspection based on C8051F320,describes all modules hardware and software design of inspection instrument.The inspection instrument has the function of information collection, axle’s temperature detection, lighting and records storage.It can supervise and administer train safety inspection work effectively.The system software using C51 can manage the power of single chip microcomputer, and guarantee the stability, reliability and low power consumption of the inspection instrument.
上传时间： 2013-12-22
上传用户：落花无痕
基于CC1110单片机公交报站系统主要由CC1110单片机最小系统和WT588D语音模块组成，提出了如何实现语音报站，通过无线通信SimpliciTI网络协议实现公交站台的自动播报和OLCD液晶显示公交运行的各类信息。结果表明，该公交报站系统报站准确率99%，价格比同类产品下降了300%以上，系统组成结构简单，提高了系统的抗干扰性和稳定性，也便于携带。 Abstract: The bus stop announcement system based on CC1110 MCU is composed of CC1110 MCU minimum system and WT588D voice module. How to achieve the voice announcing is put forward.The bus-stop will announce automatically and display on the OLCD by means of wireless communication SimpliciTI network protocol. As a result， the bus station stop announcement systems reported 99% accuracy rate， price of similar products declined by 300% or more， system of simple structure， improve the anti-jamming and stability of the power system， it is also portable.
上传时间： 2013-10-21
上传用户：baby25825
为深入了解基于UC3854A控制的PFC变换器中的动力学特性，研究系统参数变化对变换器中分岔现象的影响，在建立Boost PFC变换器双闭环数学模型的基础上，用Matlab软件对变换器中慢时标分岔及混沌等不稳定现象进行了仿真。在对PFC变换器中慢时标分岔现象仿真的基础上，分析了系统参数变化对分岔点的影响，并进行了仿真验证。仿真结果清晰地显示了输入整流电压的幅值变化对系统分岔点的影响。 Abstract: In order to better understand the dynamics characteristic of power factor correction converter based on UC3854A， and make the way that parameters change influences the bifurcation phenomena of the system clearly. The math model of the two closed loop circuits to the Boost PFC （Power Factor Correction） converter controller was built. Then， with the help of Matlab， the simulation for nonlinear phenomena such as chaos and slow-scale bifurcation in the PFC converter was made. Finally the factors that have influence to the phenomenon of bifurcation under slow-scale in PFC converter were analyzed. The simulation results clearly show the parameters change influences the bifurcation point of the system.
上传时间： 2013-10-17
上传用户：杜莹12345
介绍一种应用于长城赛弗SUV汽车后门车窗多功能控制器，能实现对电动玻璃车窗、车窗雨刮器、喷水器以及电加热除霜器等控制。介绍了基于NXP P89LPC922单片机多功能汽车后车窗控制器的控制功能、硬件电路原理和软件设计方法。 Abstract: This paper presents a multipurpose automotive rear windows controller for CHANGCHENG SAFE SUV.The controller can control rear power-operated window,rear wiping,washing water pump and rear defroster of the windows. In this paper, it is introduced in detail that the functions and the design of the circuit and program of the controller based on NXP P89LPC922 MCU.
上传时间： 2013-11-13
上传用户：z754970244
介绍了电力操作电源与智能电池巡检系统的特点，给出了一种基于超低功耗单片机MSP430 F149针对中小型变电站自动化运行的专用设备的基本设计原理及实现方法，最后给出了详细硬件构成和软件实现。该系统能满足中小型变电站安全、可靠、自动运行的要求，并通过与上位机的串行通信实现变电站的远程管理和控制。 Abstract: The characters of the intelligent battery data logging system of the electric operation power are introduced.The basic design principle and the implemented methods of the special equipment which only designed for the middle or small transformer substation based on MSP430F149 are prescribed. Finally, the hardware block diagram and the software flow chart are also given. The function that the system finally needs to realize can basically meet with the middle or small transformer substation’s satisfy, reliably,and automatic running.And it can also realize the transformer substation long-distance management and control by serial communicating with the host computer.
上传时间： 2013-11-25
上传用户：黄华强
利用AT89C51型单片机定时和中断功能，配以LM386型音频功率放大器，构成了作息号音自动播放器，为学校和机关管理提供方便。 Abstract: Using timing and interrupt function of the AT89C51 single-chip microcomputer and the LM386 audio power amplifier.It is constituted the automatic bugle player.This player facilitates the institution and the school daily management.
上传时间： 2013-10-10
上传用户：wivai
基于幅移键控技术ASK（Amplitude-Shift Keying），以C8051F340单片机作为监测终端控制器，C8051F330D单片机作为探测节点控制器，采用半双工的通信方式，通过监控终端和探测节点的无线收发电路，实现数据的双向无线传输。收发电路采用直径为0.8 mm的漆包线自行绕制成圆形空心线圈天线，天线直径为（3.4±0.3）cm。试验表明，探测节点与监测终端的通信距离为24 cm，通过桥接方式，节点收发功率为102 mW时，节点间的通信距离可达20 cm。与传统无线收发模块相比，该无线收发电路在受体积、功耗、成本限制的场合有广阔的应用前景。 Abstract: Based on ASK technology and with the C8051F340 and C8051F330D MCU as the controller， using half-duplex communication mode， this paper achieves bi-directional data transfer. Transceiver circuit constituted by enameled wire which diameter is 0.8mm and wound into a diameter （3.4±0.3） cm circular hollow coil antenna. Tests show that the communication distance between detection and monitoring of the terminal is 24cm，the distance is up to 20cm between two nodes when using the manner of bridging and the node transceiver power is 102mW. Compared with the conventional wireless transceiver modules， the circuit has wide application prospect in small size， low cost and low power consumption and other characteristics.
上传时间： 2013-10-19
上传用户：xz85592677
为解决输油管道温度压力参数实时监测的问题，设计了以C8051F930单片机作为控制核心的超低功耗输油管道温度压力远程监测系统。现场仪表使用高精度电桥采集数据，通过433 MHz短距离无线通信网络与远程终端RTU进行通信，RTU通过GPRS网络与PC上位机进行远程数据传输，在上位机中实现数据存储和图形化界面显示，从而实现输油管道温度压力参数的实时监测和异常报警。经实验证明，该系统的12位数据采集精度满足设计要求，漏码率小于1%，正常工作时间超过5个月，能实时有效地监测输油管道的温度压力参数，节省大量人工成本，有效预防管道参数异常造成的经济损失和环境污染。 Abstract: In order to solve the problems on real-time monitoring of pipeline temperature and pressure parameters， the ultra-low power remote pipeline temperature and pressure monitoring system was designed by using the single chip processor C8051F930 as the control core. The high-precision electric bridge was used in field instruments for data collection， the 433MHz short-range wireless communication network was used to make communication between field instrument and RTU， the GPRS was used by the RTU to transmit data to the PC host computer， and the data was stored and displayed in the PC host computer， so the real-time monitoring and exception alerts of pipeline temperature and pressure parameters were achieved. The experiment proves that the system of which error rate is less than 1% over five months working with the 12-bit data acquisition accuracy can effectively monitor the pipeline temperature and pressure parameters in real time， it saves a lot of labor costs and effectively prevents environmental pollution and economic losses caused by abnormal channel parameters.
上传时间： 2013-11-07
上传用户：cuibaigao
The PCF8578 is a low power CMOS1 LCD row and column driver, designed to drive dotmatrix graphic displays at multiplex rates of 1:8, 1:16, 1:24 or 1:32. The device has40 outputs, of which 24 are programmable and configurable for the following ratios ofrows/columns: 32¤8, 24¤16, 16¤24 or 8¤32. The PCF8578 can function as a stand-alone LCDcontroller and driver for use in small systems. For larger systems it can be used inconjunction with up to 32 PCF8579s for which it has been optimized. Together these twodevices form a general purpose LCD dot matrix driver chip set, capable of driving displaysof up to 40960 dots. The PCF8578 is compatible with most microcontrollers andcommunicates via a two-line bidirectional bus (I2C-bus). Communication overhead isminimized by a display RAM with auto-incremented addressing and display bankswitching.
上传时间： 2013-10-23
上传用户：顶得柱
