When a system designer specifies a nonisolated dc/dc powermodule, considering the needed input voltage range isequally as important as considering the required performanceattributes and features. Generally, nonisolated moduleshave either a narrow or a wide input voltage range. Narrowinputmodules typically have a nominal input voltage of3.3, 5, or 12 V. For systems that operate from a tightlyregulated input bus—such as those that do not use batterybackup—a narrow-input module is often adequate sincethe input remains fairly stable.Offering greater flexibility, wide-input modules operatewithin a range of 7 to 36 V, which includes the popular12- or 24-V industrial bus. This enables a single module tobe used for generating multiple voltages. These modulesare ideal for industrial controls, HVAC systems, vehicles,medical instrumentation, and other applications that usea loosely regulated distribution bus. In addition, systemspowered by a rectifier/battery charger with lead-acidbattery backup almost always require wide-input modules.System designers who choose power supplies may wantto take a close look at the latest generation of wide-inputdc/dc modules.
標(biāo)簽： Wide-input modules offer dc
上傳時(shí)間： 2014-12-24
上傳用戶：dragonhaixm
數(shù)字控制的交流調(diào)速系統(tǒng)所選用的微處理器、功率器件及產(chǎn)生PWM波的方法是影響交流調(diào)速系統(tǒng)性能好壞的直接因素。在介紹了正弦脈寬調(diào)制(SPWM)技術(shù)的基礎(chǔ)上，設(shè)計(jì)了一種以8098單片機(jī)作為控制器，以智能功率模塊IPM為開(kāi)關(guān)器件的變頻調(diào)速系統(tǒng)。通過(guò)軟件編程，產(chǎn)生正弦脈沖寬度調(diào)制波形來(lái)控制絕緣柵雙極晶體管的導(dǎo)通和關(guān)斷，從而達(dá)到控制異步電動(dòng)機(jī)轉(zhuǎn)速的目的。實(shí)驗(yàn)結(jié)果表明，該系統(tǒng)可調(diào)頻率調(diào)電壓，穩(wěn)定度高，調(diào)速范圍寬，具有較強(qiáng)的實(shí)用價(jià)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.
標(biāo)簽： 8098 SPWM 單片機(jī) 變頻調(diào)速系統(tǒng)
上傳時(shí)間： 2013-11-14
上傳用戶：ynwbosss
在理論分析循環(huán)碼編碼和譯碼基本原理的基礎(chǔ)上，提出了基于單片機(jī)系統(tǒng)的(24，16)循環(huán)碼軟件實(shí)現(xiàn)編碼、譯碼的方案。仿真結(jié)果表明(24，16)循環(huán)碼能有效地克服來(lái)自通訊信道的干擾，保證數(shù)據(jù)通信的可靠及系統(tǒng)的穩(wěn)定，使誤碼率大幅度降低。本論文對(duì)(24，16)循環(huán)碼的研究結(jié)果表明，可以有效地降低錯(cuò)誤概率和提高系統(tǒng)的吞吐量，實(shí)現(xiàn)糾錯(cuò)僅需要在接收端增加有限的存儲(chǔ)空間和計(jì)算復(fù)雜度，具有一定的實(shí)用價(jià)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.
標(biāo)簽： 24 16 單片機(jī)系統(tǒng) 循環(huán)碼
上傳時(shí)間： 2013-11-09
上傳用戶：gaoliangncepu
便攜式信號(hào)采集在機(jī)器健康診斷系統(tǒng)中有較高的應(yīng)用價(jià)值。機(jī)器健康診斷的信號(hào)特點(diǎn)是包括低頻信號(hào)。本文研究是為了實(shí)現(xiàn)簡(jiǎn)易而且低成本的低頻便攜式信號(hào)采集。以Microchip公司單片機(jī)PIC18F1320為核心設(shè)計(jì)信號(hào)采集電路，實(shí)現(xiàn)了信號(hào)的采集和保存。系統(tǒng)采用串行電可擦除芯片24LC32A保存數(shù)據(jù)，經(jīng)過(guò)有線通信，信號(hào)數(shù)據(jù)由串行口通過(guò)MAX232芯片輸送到微型計(jì)算機(jī)接收和保存，最后繪制出信號(hào)波形。 微型計(jì)算機(jī)程序采用Visual Basic編程。研究成功采樣頻率為3 kHz的復(fù)雜信號(hào)，證明該方案符合設(shè)計(jì)要求。 Abstract: Portable signal acquisition is useful in machine health monitoring systems. The signal characteristics of machine health monitoring includes low frequency signals. The goal of this study is to realize simple, inexpensive and portable low frequency signal sampling. This paper provides the project of signal acquisition system design based on PIC18F1320 microcontroller manufactured by the Microchip Technology Incorporation to achieve signal sampling and storage. The system adopted EEPROM 24LC32A to store the signal data. The microcomputer received data via wired link with the MAX232 IC through the serial port. The microcomputer program, programmed in Visual Basic, received the data, stored it and plotted the signal. The study successfully samples 3kHz complicated signals and thus meets the design requirement.
上傳時(shí)間： 2013-11-19
上傳用戶：moerwang
為了提高傳統(tǒng)溫度控制系統(tǒng)的性能，將PID控制理論與嵌入式系統(tǒng)相結(jié)合，采用瑞薩電子公司的H8S/2166作為核心處理器，AD公司的AD7705以及熱敏電阻溫度傳感器作為溫度檢測(cè)單元，利用4×6小鍵盤(pán)、LCD顯示器和S1D13305液晶控制器達(dá)到良好的人機(jī)交互，設(shè)計(jì)出了一個(gè)應(yīng)用于化工領(lǐng)域的嵌入式實(shí)時(shí)溫度控制系統(tǒng)。相比于傳統(tǒng)溫度控制系統(tǒng)，該系統(tǒng)提供了更強(qiáng)的計(jì)算能力和可擴(kuò)展能力，采用增量PID控制算法實(shí)現(xiàn)復(fù)雜控制。通過(guò)實(shí)驗(yàn)，該系統(tǒng)能達(dá)到0.1 ℃的溫度控制精度以及小于120 s的溫度穩(wěn)定時(shí)間。 Abstract: In order to improve the performance of conventional temperature control system， combining PID control theory with embedded systems， using the Renesas Electronics Corp. H8S/2166 micro-controller as a core processors， AD7705 and thermistor temperature sensor as a temperature detection unit and 4×6 small keyboard， LCD and S1D13305 LCD controller as a good human-computer interaction， this paper designed an embedded real-time temperature control system which is applied in chemical industry. Compared with conventional temperature control system， this system provides more computing power and extensibility， and adopts PID control algorithm for complex control. Through the experiment， the system can reach temperature control accuracy of 0.1 ℃ and temperature stabilization time of less than 120 seconds.
標(biāo)簽： 瑞薩電子 微控制器 溫度控制 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2014-12-26
上傳用戶：003030
以C8051F020為核心處理器，設(shè)計(jì)無(wú)線傳感器網(wǎng)絡(luò)數(shù)據(jù)采集系統(tǒng)。系統(tǒng)采用SZ05-ADV型無(wú)線通訊模塊組建Zigbee無(wú)線網(wǎng)絡(luò)，結(jié)合嵌入式系統(tǒng)的軟硬件技術(shù)，完成終端節(jié)點(diǎn)的8路傳感器信號(hào)的數(shù)據(jù)采集。現(xiàn)場(chǎng)8路信號(hào)通過(guò)前端處理后，分別送入C8051F020的12位A/D轉(zhuǎn)換器進(jìn)行轉(zhuǎn)換。經(jīng)過(guò)精確處理、存儲(chǔ)后的現(xiàn)場(chǎng)數(shù)據(jù)，通過(guò)Zigbee無(wú)線網(wǎng)絡(luò)傳送到上位機(jī)，系統(tǒng)可達(dá)到汽車試驗(yàn)中無(wú)線測(cè)試的目的。 Abstract: This paper designs a wireless sensor network system for data acquisition with C8051F020 as core processors.The system used SZ05-ADV wireless communication module，set up a Zigbee wireless network， combined with hardware and software technologies of embedded systems，completed the end-node 8-locale sensor signal data acquisition.Eight locale signals were sent separately into the 12-bit ADC of C8051F020 for conversion through front treatment.After accurate processing and storage，the locale data was transmitted to the host computer through Zigbee wireless.The system achieves the purpose of wireless testing in vehicle trial.
標(biāo)簽： C8051F020 Zigbee 汽車測(cè)試 系統(tǒng)設(shè)計(jì)
上傳時(shí)間： 2013-11-23
上傳用戶：dsgkjgkjg
介紹了當(dāng)前普通標(biāo)記機(jī)控制系統(tǒng)現(xiàn)狀及其存在缺點(diǎn)，給出氣動(dòng)標(biāo)記機(jī)及相頻修正PWM模式的工作原理。采用ATmega16單片機(jī)和USB轉(zhuǎn)換RS232接口器件CH341T實(shí)現(xiàn)驅(qū)動(dòng)控制系統(tǒng)與PC的實(shí)時(shí)通訊，標(biāo)記控制系統(tǒng)可升級(jí)到USB接口。采用基于ATmega16的相頻修正PWM替換555振蕩電路產(chǎn)生的PWM，可直接通過(guò)軟件調(diào)整PWM信號(hào)。使用達(dá)林頓三極管TIP122替代直流繼電器驅(qū)動(dòng)高頻電磁閥，使得電磁閥驅(qū)動(dòng)電路簡(jiǎn)單，成本低廉。該控制系統(tǒng)已成功應(yīng)用于氣動(dòng)標(biāo)記機(jī)。 Abstract: In this paper,the actuality and demerit of the common gas marking machine control systems are described.The operation principle of the gas marking machine and the phase and frequency correct PWM of ATmega16is introduced.The real-time communication between the driving control system and PC by CH341T which its function is translated USB to RS232is realized,the control systems is updated grade to USB interface.The PWM signal can be adjustable by software for the555surge circuit was substituted by the phase and frequency.The high frequency electromagnetic value’s driving circuit by DC relay is replaced by TIP122,therefore,the circuit is become simple and the cost cheap.The control systems has been widely used in gas marking machine.
標(biāo)簽： ATmega 16 標(biāo)記 控制系統(tǒng)
上傳時(shí)間： 2013-10-18
上傳用戶：1427796291
基于CC1110單片機(jī)公交報(bào)站系統(tǒng)主要由CC1110單片機(jī)最小系統(tǒng)和WT588D語(yǔ)音模塊組成，提出了如何實(shí)現(xiàn)語(yǔ)音報(bào)站，通過(guò)無(wú)線通信SimpliciTI網(wǎng)絡(luò)協(xié)議實(shí)現(xiàn)公交站臺(tái)的自動(dòng)播報(bào)和OLCD液晶顯示公交運(yùn)行的各類信息。結(jié)果表明，該公交報(bào)站系統(tǒng)報(bào)站準(zhǔn)確率99%，價(jià)格比同類產(chǎn)品下降了300%以上，系統(tǒng)組成結(jié)構(gòu)簡(jiǎn)單，提高了系統(tǒng)的抗干擾性和穩(wěn)定性，也便于攜帶。 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.
標(biāo)簽： 1110 CC 單片機(jī) 公交報(bào)站
上傳時(shí)間： 2013-10-21
上傳用戶：baby25825
以AVR單片機(jī)ATmega8和USB接口器件PDIUSBD12為核心，基于標(biāo)準(zhǔn)的USB1.1協(xié)議，設(shè)計(jì)一種通用USB接口模塊，以滿足嵌入式系統(tǒng)中對(duì)USB接口的需求。對(duì)模塊的硬件電路或單片機(jī)固件程序的硬件接口層稍加修改即可用于其他各種微處理器。該模塊可為各種嵌入式系統(tǒng)增加USB接口,實(shí)現(xiàn)與USB主機(jī)系統(tǒng)通信。 Abstract: Based on AVR microcontroller ATmega8 and USB interface chip PDIUSBD12, a general USB interface module is designed according to USB1.1 protocol for various requirements of embedded systems. Only with few modifications in circuit or hardware abstract layer of firmware, the module can be used on many types of microprocessors. All kinds of embedded systems can realize high speed and stable communication with USB host systems, owing to the facility of this module.
標(biāo)簽： AVR USB 單片機(jī) 接口設(shè)計(jì)
上傳時(shí)間： 2014-01-08
上傳用戶：趙云興
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.
標(biāo)簽： 8578 PCF LCD 圖形點(diǎn)陣
上傳時(shí)間： 2013-10-23
上傳用戶：頂?shù)弥?/p>
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