ADI ADuC7027 工业过程控制PLC开发方案
发布时间:2011-12-15 12:34
发布者:Liming
ADI 公司的ADuC7027是集成了12位模拟I/O, ARM7TDMI® MCU的精密模拟微控制器,采用ARM7TDMI核16位/32位RISC架构,片内振荡器精度±3%,外接时钟源高达44MHz, 41.78 MHz PLL具有可编程分频器. 模拟I/O具有多路12位1MSPS ADC和12位电压输出DAC.器件工作电压2.7V-3.3V,主要用在工业控制和自动化系统,智能传感器,精密仪表,基站系统,光网络等.本文介绍了ADuC702x 主要特性,方框图,典型应用电路,以及PLC评估系统主要特性, 系统总体框图,多种输入/输出电路,输入和输出与电源保护电路. 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 应用: Industrial control and automation systems Smart sensors, precision instrumentation Base station systems, optical networking 图1.ADuC702x功能方框图 图2.ADuC702x典型应用电路图 PLC评估系统 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. 图3.PLC评估系统外形图 PLC评估系统主要特性: 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 图4.PLC评估系统总体框图 图5.PLC评估系统输入通路1和通路2-电压和电流输入 图6.PLC评估系统输入通路3和通路4-电压和电流输入 图7.PLC评估系统热电耦输入电路 图8.PLC评估系统3线RTD输入电路 图9.PLC评估系统输出通路3和输出通路4-电压和电流输出 图10.PLC评估系统电源输出保护电路 图11.PLC评估系统模拟输入保护电路(1) 图12.PLC评估系统模拟输入保护电路(2) 图13.PLC评估系统模拟输出保护电路 详情请见: http://www.analog.com/en/digital-to-analog-converters/products/evaluation-boardstools/CU_eb_PLC_DEMO_SYSTEM/resources/fca.html |
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