Industrial remote monitoring systems and keep-alivecircuits spend most of their time in standby mode. Manyof these systems also depend on battery power, so powersupply effi ciency in standby state is very important tomaximize battery life. The LT®8410/-1 high effi ciencyboost converter is ideal for these systems, requiringonly 8.5μA of quiescent current in standby mode. Thedevice integrates high value (12.4M/0.4M) output feedbackresistors, signifi cantly reducing input current whenthe output is in regulation with no load. Other featuresinclude an integrated 40V switch and Schottky diode,output disconnect with current limit, built in soft-start,overvoltage protection and a wide input range, all in atiny 8-pin 2mm × 2mm DFN package.
上传时间: 2013-11-23
上传用户:新手无忧
PLCC-44 封装尺寸图P-44A
上传时间: 2013-11-13
上传用户:84425894
Analog Inputs and Outputs in an S7 PLC are represented in the PLC as a 16-bit integer. Over the nominal span of the analog input or output, the value of this integer will range between - 27648 and +27648. However, it is easier to use the analog values if they are scaled to the same units and ranges as the process being controlled. This applications tip describes methods for scaling analog values to and from engineering units.
上传时间: 2013-11-17
上传用户:3294322651
数字控制的交流调速系统所选用的微处理器、功率器件及产生PWM波的方法是影响交流调速系统性能好坏的直接因素。在介绍了正弦脉宽调制(SPWM)技术的基础上,设计了一种以8098单片机作为控制器,以智能功率模块IPM为开关器件的变频调速系统。通过软件编程,产生正弦脉冲宽度调制波形来控制绝缘栅双极晶体管的导通和关断,从而达到控制异步电动机转速的目的。实验结果表明,该系统可调频率调电压,稳定度高,调速范围宽,具有较强的实用价值 Abstract: AC variable speed with digital control systems used microprocessors, power devices and generate PWM wave is the direct factors of affecting the performance AC speed regulation system. On the basis of introducing the sinusoidal pulse width modulation (SPWM) technology,this paper designed variable speed system which used 8098 as a controller, intelligent power module IPM as switching device. Through software programming, resulting in sinusoidal pulse width modulation waveform to control the insulated gate bipolar transistor turn on and off, so as to achieve the purpose of speed control of induction motors. Experimental results show that the system can adjust frequency modulation voltage, high stability, wide speed range, has a strong practical value.
上传时间: 2013-11-14
上传用户:ynwbosss
在理论分析循环码编码和译码基本原理的基础上,提出了基于单片机系统的(24,16)循环码软件实现编码、译码的方案。仿真结果表明(24,16)循环码能有效地克服来自通讯信道的干扰,保证数据通信的可靠及系统的稳定,使误码率大幅度降低。本论文对(24,16)循环码的研究结果表明,可以有效地降低错误概率和提高系统的吞吐量,实现纠错仅需要在接收端增加有限的存储空间和计算复杂度,具有一定的实用价值。 Abstract: Based on analyzing the theory of encoding and decoding of cyclic code, this paper showed the schemes of encoding and decoding of(24,16)cyclic code by the software and based on microcontroller. Simulation results show that using (24,16) cyclic codes can effectively overcome the interference from communication channel, ensure the reliability and stability of data communication systems, and reduce the bit error rate greatly. The results of this paper show that by using the (24,16) cyclic code, the error rate can be reduced and the system throughput can be improved. Meanwhile, the system only needs to enlarge limited storage space and computation the complexity at the receiving end to realize error correction. Thus the (24,16) cyclic code has a practical value.
上传时间: 2013-11-09
上传用户:gaoliangncepu
设计了一种基于PIC16C71单片机的数字水温配制阀。该配制阀采用NTC热敏电阻作温度传感器,与固定电阻组成简单分压电路作为水温测量电路,利用PIC16C71单片机内置的8位A/D转换器把热敏电阻上的模拟电压转换为数字量,PIC16C71单片机控制直流电机驱动混水阀调节冷热水的混合比例实现水温调节。给出了控制电路图,对水温测量电路的参数选择和测温精度作了详细讨论。实验和分析表明,选用阻值较大的NTC热敏电阻和分压电阻可较好地解决热敏电阻因功耗较大造成的热击穿问题。 Abstract: A digital valve for controlling water temperature based on PIC16C71 was presented in this paper.A bleeder circuit which consisted of a NTC thermistor as temperature sensor and a fixed resistance was designed as water temperature measuring circuit.The analog voltage on the thermistor was converted into digital signal by a 8-bit A/D converter embedded in PIC16C71. Based on the digital signal, the MCU PIC16C71 drived the valve by a DC motor to adjust the water temperature through adjusting the proportion of hot water and cold water.The circuit diagram of controller was given,the principle,the component parameters and the accuracy of measuring temperatures were also dissertated in detail. It was found by experiment and analysis that thermal breakdown of thermistor caused by high power could be solved by selecting thermistor and fixed resistance with high impedance value.
上传时间: 2013-11-08
上传用户:Yue Zhong
假定从8位AD中读取数据(如果是更高位的AD可定义数据类型为int),子程序为get_ad(); 1、限幅滤波法(又称程序判断滤波法) A、方法: 根据经验判断,确定两次采样允许的最大偏差值(设为A) 每次检测到新值时判断: 如果本次值与上次值之差<=A,则本次值有效 如果本次值与上次值之差>A,则本次值无效,放弃本次值,用上次值代替本次值 B、优点: 能有效克服因偶然因素引起的脉冲干扰 C、缺点 无法抑制那种周期性的干扰 平滑度差 /* A值可根据实际情况调整 value为有效值,new_value为当前采样值 滤波程序返回有效的实际值 */ #define A 10 char value; char filter() { char new_value; new_value = get_ad(); if ( ( new_value - value > A ) || ( value - new_value > A ) return value; return new_value; } 2、中位值滤波法 A、方法: 连续采样N次(N取奇数) 把N次采样值按大小排列 取中间值为本次有效值 B、优点: 能有效克服因偶然因素引起的波动干扰 对温度、液位的变化缓慢的被测参数有良好的滤波效果 C、缺点: 对流量、速度等快速变化的参数不宜 /* N值可根据实际情况调整 排序采用冒泡法*/
上传时间: 2014-12-26
上传用户:nanshan
设计一种基于ATmega16L单片机的温度控制系统,阐述该系统的软硬件设计方案。采用模块化设计方法,利用增量式PID算法使被控对象的温度值趋于给定值。实验结果表明该系统具有良好的检测和控制功能。 Abstract: This paper designs a temperature control system based on ATmega16L,describes the hardware and software de-sign scheme of the system,adopts the modularized design method and utilizes the incremental PID algorithm to realize the temperature of controlled device incline to the given value.The experiment result indicates that the system has good detec-tion and control function
上传时间: 2013-10-09
上传用户:stvnash
基于PIC单片机的脉冲电源:设计了一种金属凝固过程用脉冲电源。该电源采用PIC16F877作为主控芯片,实现对窄脉冲电流幅值的检测,以及时电流脉冲幅值根据模糊PID算法进行闲环控制。使用结果表明:该电源的输出脉冲波形良好,电流幅值稳定,满足合金材料凝固过程的工艺要求且运行稳定可靠。关键词:脉冲电源;PIC16F877单片机;模糊PID;闲环控制 Abstract:A kind of pulse power supply was designed which uses in the metal solidification process ..I11is power supply used PIC16F877 to take the master control chip reali on to the narrow pulse electric current peak-to-peak value examination,carried on the closed-loop control to the electric current pulse peak-to-peak value basis fuzzy PID algorithm.The use result indicated ,this power supply output se profile is good,and the electric current peak-to-p~k value is stable,It satisfies the alloy material solidification process the technological requirement and movement stable reliable,Key words:p se po wer supply;PIC16F877single-chip microcontroller;f r PID;closed-loop control
上传时间: 2013-10-27
上传用户:xcy122677
基于单片机控制的二氧化碳浓度测试计:基于CDM4161二氧化碳气体浓度测试模块以及ATtiny26单片机,提出了一种二氧化碳浓度测试计的设计方案。该方案具有硬件电路简单、成本低、可靠性高、测量准确等优点,具有较高的实用价值。 Abstract: Abstract:A desigh scheme of CO2 concentration meter based on CDM4161carbon dioxide concentration test module and ATtiny26micro-controller is presented in this paper.The design scheme features simple hardware circuit,low-cost,high reli-ability,accurate measurement and it has a high practical value.
上传时间: 2013-11-14
上传用户:zjwangyichao