為了解決磁放大器性能測(cè)試過(guò)程中，需要對(duì)其供給不同數(shù)值恒定電流的問(wèn)題，設(shè)計(jì)了一種基于DAC7512和單片機(jī)的數(shù)控恒流源系統(tǒng)。該系統(tǒng)采用AT89C51作為主控器件，將計(jì)算機(jī)發(fā)送的電流控制字命令轉(zhuǎn)換為D/A轉(zhuǎn)換器控制字，通過(guò)模擬SPI通信接口，寫(xiě)D/A控制字到DAC7512，從而控制其輸出相應(yīng)數(shù)字電壓值，經(jīng)差動(dòng)縮放電路、電壓/電路變換電路和功率驅(qū)動(dòng)電路，最后輸出恒定電流。實(shí)驗(yàn)結(jié)果表明，恒流源輸出電流調(diào)節(jié)范圍為-45~+45 mA、精度為±0.1 mA，分辨率達(dá)0.024 4 mA，具有應(yīng)用靈活，外圍電路簡(jiǎn)單，可靠性高的特點(diǎn)。該數(shù)控直流恒流源也可為相關(guān)產(chǎn)品的測(cè)試系統(tǒng)研發(fā)提供參考。 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
標(biāo)簽： 7512 DAC 數(shù)控直流 恒流源
上傳時(shí)間： 2014-12-27
上傳用戶(hù)：invtnewer
介紹了一種基于MSP430系列單片機(jī)和ADXL203加速度傳感器的數(shù)字式傾角儀，它不僅可以實(shí)現(xiàn)水平度檢測(cè)，而且可以測(cè)量00～3600范圍內(nèi)的任意傾角，分辨率可達(dá)O．1。。此外，由于該傾角儀輸出為數(shù)字結(jié)果，因此它也可以與其他的數(shù)字設(shè)備結(jié)合起來(lái)，組合成一個(gè)功能更加強(qiáng)大的儀器。該數(shù)字傾角儀可廣泛應(yīng)用于建筑、機(jī)械、道路、橋梁、石油、煤礦和地質(zhì)勘探等各種需要測(cè)量重力參考系下傾角的場(chǎng)合。關(guān)鍵詞：MSP430F133單片機(jī)；力敏傳感器；ADXL203加速度計(jì)；角度測(cè)量 Abstract：This paper presents a new style digital inclinometer which is developed on the basis of the MSP430F133 MCU and the ADXL203 dual axis aeeelerometer．This inclinometer not only can test levelness，but also can measure any angle between 0。and 360。with an accuracy of 0．1 O．In addition，its Output is a digital result，which makes it possible to integrate itself with other digital devices to form a more functional unit．This inclinometer can be widely used in any construction site，oil field，coal-mine or geologic survey and SO on where it will provide the working people with convenience to measure any angles．Key words：MSP430F133 MCU；force sensor；ADXL203 accelerometer；angle measurement
上傳時(shí)間： 2013-11-14
上傳用戶(hù)：lizhizheng88
The SN65LBC170 and SN75LBC170 aremonolithic integrated circuits designed forbidirectional data communication on multipointbus-transmission lines. Potential applicationsinclude serial or parallel data transmission, cabledperipheral buses with twin axial, ribbon, ortwisted-pair cabling. These devices are suitablefor FAST-20 SCSI and can transmit or receivedata pulses as short as 25 ns, with skew lessthan 3 ns.These devices combine three 3-state differentialline drivers and three differential input linereceivers, all of which operate from a single 5-Vpower supply.The driver differential Outputs and the receiverdifferential inputs are connected internally to formthree differential input/Output (I/O) bus ports thatare designed to offer minimum loading to the buswhenever the driver is disabled or VCC = 0. Theseports feature a wide common-mode voltage rangemaking the device suitable for party-lineapplications over long cable runs.
上傳時(shí)間： 2013-10-13
上傳用戶(hù)：ytulpx
要搞清楚單片機(jī)與PLC的異同，首先得明確什幺是單片機(jī)，什幺是PLC。對(duì)此，我們簡(jiǎn)要回顧一下計(jì)算機(jī)的發(fā)展歷程也許有幫助，按計(jì)算機(jī)專(zhuān)家的原始定義，計(jì)算機(jī)系統(tǒng)由五大部分--即控制單元（CU）、算術(shù)運(yùn)算單元（ALU）、存儲(chǔ)器（Memory）、輸入設(shè)備（Input）、輸出設(shè)備（Output）組成。早期計(jì)算機(jī)（晶體管的或集成電路的，不包括電子管的）的CU或ALU由一塊甚至多塊電路板組成，CU和ALU是分離的，隨著集成度的提高，CU和ALU合在一塊就組成了中央處理單元（CPU）,接著將CPU集成到單塊集成電路中就產(chǎn)生MPU或MCU,出現(xiàn)了如Intel4004、8008、8080，8085、8086、8088、Z80等MPU。此后，MPU的發(fā)展產(chǎn)生了兩條分支，一支往高性能、高速度、大容量方向發(fā)展，典型芯片如：Intel80186、286、386、486、586、P2、P3、P4等，速度從4.7MHz到現(xiàn)在的3.2GHz。另一支則往多功能方向發(fā)展，將存儲(chǔ)器(ROM、PROM、EPROM、EEPROM、FLASHROM、SRAM等)、輸入/出接口（Timer/Counter、PWM、ADC/DAC、UART、IIC、SPI、RTC、PCA、FPGA等）全部集成在一塊集成電路中而成為SOC。依愚之見(jiàn)，這就是當(dāng)今廣泛應(yīng)用的單片計(jì)算機(jī)，簡(jiǎn)稱(chēng)單片機(jī)。這一分支可謂品種繁多，位寬從8位到32位，引腳數(shù)從6個(gè)到幾百個(gè)，工作頻率從幾十KHz到幾百M(fèi)Hz,體系結(jié)構(gòu)既有CISC也有RISC,數(shù)不勝數(shù)。常用的有MCS-51系列、MCS-96系列、PIC系列、AVR系列、ARM7/9系列、TMS320系列、MSP430系列、MOTOROLA眾多的單片機(jī)等等。
上傳時(shí)間： 2013-10-16
上傳用戶(hù)：jjj0202
FEATURES400 MSPS internal clock speedIntegrated 10-bit DAC32-bit tuning wordPhase noise ≤ –120 dBc/Hz @ 1 kHz offset (DAC Output)Excellent dynamic performance>75 dB SFDR @ 160 MHz (±100 kHz offset) AOUTSerial I/O control1.8 V power supplySoftware and hardware controlled power-down48-lead TQFP/EP packageSupport for 5 V input levels on most digital inputsPLL REFCLK multiplier (4× to 20×)Internal oscillator; can be driven by a single crystalPhase modulation capabilityMultichip synchronization
上傳時(shí)間： 2014-12-04
上傳用戶(hù)：axin881314
The PCA9536 is an 8-pin CMOS device that provides 4 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.
上傳時(shí)間： 2013-10-27
上傳用戶(hù)：w230825hy
The PCA9534 is a 16-pin CMOS device that provide 8 bits of General Purpose parallel Input/Output (GPIO) expansion for I2C-bus/SMBus applications and was developed to enhance the NXP Semiconductors family of I2C-bus I/O expanders. The improvements include higher drive capability, 5 V I/O tolerance, lower supply current, individual I/O configuration, 400 kHz clock frequency, and smaller packaging. I/O expanders provide a simple solution when additional I/O is needed for ACPI power switches, sensors, push buttons, LEDs, fans, etc.
上傳時(shí)間： 2013-11-17
上傳用戶(hù)：vodssv
The CAT25128 is a 128−Kb Serial CMOS EEPROM device internally organized as 16Kx8 bits. This features a 64−byte page write buffer and supports the Serial Peripheral Interface (SPI) protocol. The device is enabled through a Chip Select (CS) input. In addition, the required bus signals are clock input (SCK), data input (SI) and data Output (SO) lines. The HOLD input may be used to pause any serial communication with the CAT25128 device. The device featuressoftware and hardware write protection, including partial as well as full array protection.
標(biāo)簽： 25128 EEPRO CMOS CAT
上傳時(shí)間： 2013-11-15
上傳用戶(hù)：fklinran
The CAT823, CAT824, and CAT825 provide basic reset and monitoring functions for the electronic systems. Each device monitors the system voltage and maintains a reset Output until that voltage reaches the device’s specified trip value and then maintains the reset Output active condition until the device’s internal timer, after a minimum timer of 140ms; toallow the systems power supply to stabilize.
上傳時(shí)間： 2014-11-18
上傳用戶(hù)：BOBOniu
The PAM2862 is a continuous mode inductivestep-down converter, designed for driving singleor multiple series connected LEDs efficientlyfrom a voltage source higher than the LEDvoltage. The device operates from an inputupply between 6V and 30V and provides anexternally adjustable Output current of up to 1A.Depending upon supply voltage and externalcomponents, this can provide up to 24 watts ofOutput power.
標(biāo)簽： Driver 2862 with PAM
上傳時(shí)間： 2013-11-16
上傳用戶(hù)：司令部正軍級(jí)
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