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.
上傳時間： 2013-11-17
上傳用戶：3294322651
數字控制的交流調速系統所選用的微處理器、功率器件及產生PWM波的方法是影響交流調速系統性能好壞的直接因素。在介紹了正弦脈寬調制(SPWM)技術的基礎上，設計了一種以8098單片機作為控制器，以智能功率模塊IPM為開關器件的變頻調速系統。通過軟件編程，產生正弦脈沖寬度調制波形來控制絕緣柵雙極晶體管的導通和關斷，從而達到控制異步電動機轉速的目的。實驗結果表明，該系統可調頻率調電壓，穩定度高，調速范圍寬，具有較強的實用價值 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.
上傳時間： 2013-11-14
上傳用戶：ynwbosss
HIGH SPEED 8051 μC CORE - Pipe-lined Instruction Architecture; Executes 70% of Instructions in 1 or 2 System Clocks - Up to 25MIPS Throughput with 25MHz System Clock - 22 Vectored Interrupt Sources MEMORY - 4352 Bytes Internal Data RAM (256 + 4k) - 64k Bytes In-System Programmable FLASH Program Memory - External Parallel Data Memory Interface – up to 5Mbytes/sec DIGITAL PERIPHERALS - 64 Port I/O; All are 5V tolerant - Hardware SMBusTM (I2CTM Compatible), SPITM, and Two UART Serial Ports Available Concurrently - Programmable 16-bit Counter/Timer Array with 5 Capture/Compare Modules - 5 General Purpose 16-bit Counter/Timers - Dedicated Watch-Dog Timer; Bi-directional Reset CLOCK SOURCES - Internal Programmable Oscillator: 2-to-16MHz - External Oscillator: Crystal, RC, C, or Clock - Real-Time Clock Mode using Timer 3 or PCA SUPPLY VOLTAGE ........................ 2.7V to 3.6V - Typical Operating Current: 10mA @ 25MHz - Multiple Power Saving Sleep and Shutdown Modes 100-Pin TQFP (64-Pin Version Available) Temperature Range: –40°C to +85°C
標簽： C8051F020
上傳時間： 2013-10-12
上傳用戶：lalalal
Digitemp Junior – An RS-232 Port-Powered Digital Thermometer Digitemp Jr. is a device that is designed to measure and report ambient temperature. When connected to an RS-232 port on any PC, it will periodically measure and report in ASCII form the ambient temperature in degrees Celsius. These temperature readings can be monitored with any terminal program. If the terminal program supports capture to disk, the temperature readings can be saved to disk for further analysis with a spreadsheet program or other data analysis tool. The simple ASCII output format of Digitemp Jr. makes it rel- atively easy to write custom software for receiving, recording, and analyzing ambient temperature data. Best of all, Digitemp Jr. requires no external power sup- plies or batteries. It is powered directly by the RS-232 port.
上傳時間： 2013-10-21
上傳用戶：baitouyu
為解決電致變色器件的顏色變化受外界環境顏色控制的問題，設計了一種基于單片機的便攜式顏色自適應識別電路。與傳統顏色識別電路相比較，該電路利用數字式的顏色傳感器來獲取外界環境顏色，產生的數字顏色信號易于單片機進行處理。在電路中，下位機部分主要負責獲取電致變色器件變色參數及控制電致變色器件的顏色變化;而上位機部分主要負責把下位機獲取的電致變色器件變色參數進行電壓到顏色的曲線擬合，并通過藍牙通信把擬合曲線參數傳遞給下位機。結果表明，該電路能自動根據環境顏色提供-4~4 V范圍步進為0.1 V的電壓來驅動電致變色器件的顏色顯示，與傳統的顏色識別電路設計相比，識別的精度和速度都得到了明顯改善。 Abstract: In this paper， a portable adaptive circuit for color identification(PACCI) based on MCU was designed. Compared to the traditional color identification circuit， the PACCI adopts digital sensor to detect the color data from external environment and further generate digital color data， which can be processed easily by MCU. In PACCI， the slave is mainly responsible for detecting the color parameters of the corresponding elcreochromic device and further driving it. For the master， which is mainly responsible for the color curve fitting based on the parameters of the electrochromic device， and transmits the fitting parameters to the slave through the bluetooth device. The results show that the PACCI can provide the basis voltage range from -4V to 4V automatically based on the colors of external environment with step as 0.1V to drive the corresponding electrochromic device. Compared to the traditional color recognition circuit， the recognition accuracy and speed of PACCI have been improved significantly.
上傳時間： 2013-11-09
上傳用戶：franktu
針對目前使用的RS232接口數字化B超鍵盤存在PC主機啟動時不能設置BIOS，提出一種PS2鍵盤的設計方法?；赪78E052D單片機，采用8通道串行A/D轉換器設計了8個TGC電位器信息采集電路，電位器位置信息以鍵盤掃描碼序列形式發送，正交編碼器信號通過XC9536XL轉換為單片機可接收的中斷信號，軟件接收到中斷信息后等效處理成按鍵。結果表明，在滿足開機可設置BIOS同時，又可實現超聲特有功能，不需要專門設計驅動程序，接口簡單，成本低。 Abstract: Aiming at the problem of the digital ultrasonic diagnostic imaging system keyboard with RS232 interface currently used couldn?蒺t set the BIOS when the PC boot， this paper proposed a design method of PS2 keyboards. Based on W78E052D microcontroller，designed eight TGC potentiometers information acquisition circuit with 8-channel serial A/D converter， potentiometer position information sent out with keyboard scan code sequentially.The control circuit based on XC9536 CPLD is used for converting the mechanical actions of the encoders into the signals that can be identified by the MCU， software received interrupt information and equivalently treatmented as key. The results show that the BIOS can be set to meet the boot， ultrasound specific functionality can be achieved at the same time， it does not require specially designed driver，the interface is simple and low cost.
上傳時間： 2013-10-10
上傳用戶：asdfasdfd
提出了一種以S3C2440A為核心處理器的銀行評價器的設計方案，并結合XILINX公司的XL95144XL型CPLD，輔助S3C2440A，實現該銀行評價器的各部分功能以及系統信號之間的相互協調。該評價器在系統設計上采用液晶屏顯示，代替了以往簡單的數碼管電路的顯示模式，在視覺上給人以全新的享受。同時，評價器增加了新的網絡供電方式，只要將評價器連接上網絡就可以正常工作，方便了客戶的使用?？傊?，此款銀行評價器采用了嵌入式系統的設計方案，大大豐富了系統功能，實現一個銀行評價器設計的新突破。 Abstract: S3C2440A of SamSung company is the core component of the embedded system. A design of bank assessor based on S3C2440A was provided in this paper. It used XL95144XL combined with S3C2440A to realize all the functions and coordination with system signals. This bank assessor used LCD to display instead of the former simple digital display and provided a new seusuous enjoment. Meanwhile，it provided a new method of network power supply，that the bank assessor could regularly work once it connected to the network，which is convenient for customers to use. In a word，this assessor takes embedded system，enriches the system’s functions and reclizes a new breakout.
標簽： S3C2440A
上傳時間： 2013-11-03
上傳用戶：taa123456
生活中許多目標的高度和水平距離需要進行測量。目前主要的測量方法，仍以傳統的皮尺丈量為主，測量效率不高，有時還很不方便，沒有技術成熟的數字式測高測距產品。以基本的數學方法為理論依據，利用遙控小車做為載體，采用角度傳感器測量角度、霍爾傳感器測量水平距離等，通過單片機LM3S615進行數據計算，實現了對待測目標物體的高度、水平距離等數據的快速、精確和數字式的測量，高度測量精度可達99.06%，水平測量精度則可達98.06%。 Abstract: In our lives， the height and horizontal distance of some goals are needed to be measured. Because the currently used methods are still traditional tape-based measuring methods， and the measuring efficiency is low and inconvenient so some kinds of digital and portable measuring methods or instruments are needed. Based on the basic math theory， this paper designed and manufactured a portable， digital and remote controlled measuring mobile small vehicle， which assembled with angle measuring sensor for angle measurement and Hall sensor for horizontal distance measuring. MCU LM3S615 calculated the height and horizontal distance data gotten from these sensors. The measuring process is simple， the measuring results are more accurate and the measuring efficiency is higher than traditional measure instruments. The accuracy of height and distance measurement can reach 99.06% and 98.06%.
上傳時間： 2013-10-30
上傳用戶：jackandlee
介紹了一種基于C8051F020單片機的多路壓力測量儀。該測量儀選用電阻應變式壓力傳感器采集壓力信號，并經放大電路處理后送入C8051F020單片機，再由C8051F020單片機內部的A/D轉換器將采集到的壓力信號進行模數轉化，然后分別對數據進行存儲和顯示。該測量儀能測量6路壓力信號，并且各測量點都能單獨檢測和設置。由于采用了C8051F020單片機，簡化了硬件電路，增強了抗干擾能力，使得測量儀具有測量精度高，沖擊小等特點。 Abstract: A measurement apparatus for multi-channel pressure based on single chip microcomputer is introduced.It can measure 6 channels signal of the pressure，and the pressure measure points can be detection and located individually.The pressure signal sampling is obtained by resistor stress-type pressure sensors，the digital signals of 6 channels are collected through amplifying and adjustment circuit of pressure signals and internal integrated A/D converter of MCU.Finally，and it realizes the function to store and display data separately.C8051F020 was used to made hardware circuit simple，and it also enhanced the anti-interference ability.It features high precision and little impact.
上傳時間： 2013-11-16
上傳用戶：yare
為降低成本和解決現有膜片鉗放大器系統中PC機的干擾問題，研究了一種基于單片機的膜片鉗放大器小系統。該系統采用ADI公司生產的ADuC841作為控制核心，并且配置相應的液晶顯示模塊LCM3202401。模擬電路部分采用高輸入阻抗的AD8627實現微電流信號的采集，并由后級電路進行信號的放大和電阻電容的補償。它具有硬件電路簡單、體積小、使用方便的特點。既可以單獨作為小系統實現采集和顯示，也可以通過紅外方式和PC機進行通訊，在PC機上進行信號的處理。 Abstract: In order to reduce cost and resolve the interferential problem with PC in existing patch clamp amplifiers, a small patch clamp amplifier system design based on microcontroller is studied. It adopts a new high performance microconverter ADuC841 by the ADI as the control core in the system, configuring a liquid crystal module LCM3202401. In the analog circuit, AD8627 with high input impedance is used to detect the low current，signal magnification, as well as resistance and capacitance compensation are accomplished by subsequent circuits. It has the advantage of simple hardware circuit design, small volume and convenient operation. It can either be used as an independent system to measure and show signal detected or transmit to PC by infrared ray.
上傳時間： 2013-11-06
上傳用戶：yy_cn
