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ADI 公司的ADuC7027是集成了12位模擬I/O, ARM7TDMI® MCU的精密模擬微控制器,采用ARM7TDMI核16位/32位RISC架構(gòu),片內(nèi)振蕩器精度±3%,外接時鐘源高達(dá)44MHz, 41.78 MHz PLL具有可編程分頻器. 模擬I/O具有多路12位1MSPS ADC和12位電壓輸出DAC.器件工作電壓2.7V-3.3V,主要用在工業(yè)控制和自動化系統(tǒng),智能傳感器,精密儀表,基站系統(tǒng),光網(wǎng)絡(luò)等.本文介紹了ADuC702x 主要特性,方框圖,典型應(yīng)用電路,以及PLC評估系統(tǒng)主要特性, 系統(tǒng)總體框圖,多種輸入/輸出電路,輸入和輸出與電源保護(hù)電路. The ADuC7019/20/21/22/24/25/26/27/28/29 are fully integrated, 1 MSPS, 12-bit data acquisition systems incorporating high performance multichannel ADCs, 16-bit/32-bit MCUs, and Flash®/EE memory on a single chip. The ADC consists of up to 12 single-ended inputs. An additional four inputs are available but are multiplexed with the four DAC output pins. The four DAC outputs are available only on certain models (ADuC7020, ADuC7026, ADuC7028, and ADuC7029). However, in many cases where the DAC outputs are not present, these pins can still be used as additional ADC inputs, giving a maximum of 16 ADC input channels. The ADC can operate in single-ended or differential input mode. The ADC input voltage is 0 V to VREF. A low drift band gap reference, temperature sensor, and voltage comparator complete the ADC peripheral set. Depending on the part model, up to four buffered voltage output DACs are available on-chip. The DAC output range is programmable to one of three voltage ranges. The devices operate from an on-chip oscillator and a PLL generating an internal high frequency clock of 41.78 MHz (UCLK). This clock is routed through a programmable clock divider from which the MCU core clock operating frequency is generated. The microcontroller core is an ARM7TDMI®, 16-bit/32-bit RISC machine, which offers up to 41 MIPS peak performance. Eight kilobytes of SRAM and 62 kilobytes of nonvolatile Flash/EE memory are provided on-chip. The ARM7TDMI core views all memory and registers as a single linear array. On-chip factory firmware supports in-circuit serial download via the UART or I2C serial interface port; nonintrusive emulation is also supported via the JTAG interface. These features are incorporated into a low cost QuickStart™ development system supporting this MicroConverter® family. The parts operate from 2.7 V to 3.6 V and are specified over an industrial temperature range of −40℃ to +125℃. When operating at 41.78 MHz, the power dissipation is typically 120 mW. ADuC702x 主要特性: Analog I/O Multichannel, 12-bit, 1 MSPS ADC Up to 16 ADC channels1 Fully differential and single-ended modes 0 V to VREF analog input range 12-bit voltage output DACs Up to 4 DAC outputs available1 On-chip voltage reference On-chip temperature sensor (±3°C) Voltage comparator Microcontroller ARM7TDMI core, 16-bit/32-bit RISC architecture JTAG port supports code download and debug Clocking options Trimmed on-chip oscillator (±3%) External watch crystal External clock source up to 44 MHz 41.78 MHz PLL with programmable divider Memory 62 kB Flash/EE memory, 8 kB SRAM In-circuit download, JTAG-based debug Software-triggered in-circuit reprogrammability On-chip peripherals UART, 2× I2C® and SPI serial I/O Up to 40-pin GPIO port1 4× general-purpose timers Wake-up and watchdog timers (WDT) Power supply monitor 3-phase, 16-bit PWM generator1 Programmable logic array (PLA) External memory interface, up to 512 kB1 Power Specified for 3 V operation Active mode: 11 mA @ 5 MHz, 40 mA @ 41.78 MHz Packages and temperature range From 40-lead 6 mm × 6 mm LFCSP to 80-lead LQFP1 Fully specified for –40°C to +125°C operation Tools Low cost QuickStart™ development system Full third-party support ADuC702x 應(yīng)用: Industrial control and automation systems Smart sensors, precision instrumentation Base station systems, optical networking 
圖1.ADuC702x功能方框圖
圖2.ADuC702x典型應(yīng)用電路圖 PLC評估系統(tǒng) The PLC demo system aims to demonstrate the complete PLC signal chain. It has four isolated input channels and four isolated output channels. The input channels have 24 bit resolution (using AD8220 IN-AMP + AD7793 Sigma Delta ADC) and each channel can be configured to accept a wide variety of input signals, from 4-20ma current loops to high voltage inputs 0-5, 0-10v, +/-5v, +/-10v. It can also accommodate RTD/TC inputs. The output channels have 16 bit resolution using the AD5422 which features an integrated output driver and built in fault detection and protection. The AD5422 has the following programmable output ranges, 4-20ma, 0-5v, 0-10v, +/-5v, +/-10v. Channel isolation is achieved using the ADuM5401 or ADuM1401. The complete design uses ADI converters, isolation technology, processors and power management products, allowing customers to evaluate the whole signal chain.
圖3.PLC評估系統(tǒng)外形圖 PLC評估系統(tǒng)主要特性: Inputs Selectable: 0-20mA, 4-20mA, 0-5V, 0-10V, ±5V, ±10V, RTD, TC Outputs Programmable: 0-20mA, 4-20mA, 0-5V, 0-10V, ±5V, ±10V FOUR ISOLATED 24 BIT ANALOG INPUT CHANNELS AD7793 24 Bit Sigma Delta ADC, 40nV Noise ADR02 Wide Operating Range, Precision reference ADR441 Ultralow Noise Voltage Reference AD8220 Instrumentation Amplifier, >80db CMRR ADUM5401 isoDigital Isolator with isoPower (up to 500mA) ADUM1401 isoDigital Isolator FOUR ISOLATED 16 BIT ANALOG OUTPUT CHANNELS AD5422 Single Channel, 16-Bit, Serial Input, Current Source & Voltage Output DAC 0.01% Typical Total Unadjusted Error (TUE) Single Chip Solution Output Fault Detection and Protection POWER/INTERFACE/CONTROL ADI ARM7 ADUC7027 ADP3339 High Accuracy Ultralow Iq, LDO ADM3251 Isolated Single Channel RS-232 Line Driver/Receiver
圖4.PLC評估系統(tǒng)總體框圖
圖5.PLC評估系統(tǒng)輸入通路1和通路2-電壓和電流輸入
圖6.PLC評估系統(tǒng)輸入通路3和通路4-電壓和電流輸入
圖7.PLC評估系統(tǒng)熱電耦輸入電路
圖8.PLC評估系統(tǒng)3線RTD輸入電路
圖9.PLC評估系統(tǒng)輸出通路3和輸出通路4-電壓和電流輸出
圖10.PLC評估系統(tǒng)電源輸出保護(hù)電路
圖11.PLC評估系統(tǒng)模擬輸入保護(hù)電路(1)
圖12.PLC評估系統(tǒng)模擬輸入保護(hù)電路(2)
圖13.PLC評估系統(tǒng)模擬輸出保護(hù)電路 詳情請見: 
ADuC7019_20_21_22_24_25_26_27_28_29[2].pdf
(1.27 MB)
UG-181[2].pdf
(541.74 KB)
http://www.analog.com/en/digital-to-analog-converters/products/evaluation-boardstools/CU_eb_PLC_DEMO_SYSTEM/resources/fca.html |
