《電子技術(shù)應(yīng)用》
您所在的位置:首頁 > 其他 > 解決方案 > ADIAD7193過程控制模擬前端CN0209解決方案

ADIAD7193過程控制模擬前端CN0209解決方案

2011-06-23

ADI公司的AD7193是具有PGA的4路4.8kHz超低噪音24位Sigma-Delta ADC,,RMS噪音為11 nV @ 4.7 Hz (gain = 128),,失調(diào)漂移為±5 nV/℃ ,,增益漂移為±1 ppm/℃,,工作電壓3V-5.25V,主要應(yīng)用在PLC/DCS模擬輸入模塊,,數(shù)據(jù)采集和應(yīng)力儀傳感器,。本文介紹了AD7193主要特性,,功能方框圖,基本的連接框圖,,流量計的典型應(yīng)用電路圖以及過程控制應(yīng)用的全編程通用模擬前端(CN0209)簡化電路圖和EVAL-CN0209-SDPZ評估板電路圖,,材料清單和PCB布局圖。

The AD7193 is a low noise, complete analog front end for high precision measurement applications. It contains a low noise, 24-bit sigma-delta (Σ-Δ) analog-to-digital converter (ADC). The on-chip low noise gain stage means that signals of small amplitude can interface directly to the ADC.

The device can be configured to have four differential inputs or eight pseudo differential inputs. The on-chip channel sequencer allows several channels to be enabled simultaneously, and the AD7193 sequentially converts on each enabled channel, simplifying communication with the part. The on-chip 4.92 MHz clock can be used as the clock source to the ADC or, alternatively, an external clock or crystal can be used. The output data rate from the part can be varied from 4.7 Hz to 4.8 kHz.

The device has a very flexible digital filter, including a fast settling option. Variables such as output data rate and settling time are dependent on the option selected. The AD7193 also includes a zero latency option.

The part operates with a power supply from 3 V to 5.25 V. It consumes a current of 4.65 mA, and it is available in a 28-lead TSSOP package and a 32-lead LFCSP package.

AD7193主要特性:

Fast settling filter option

4 differential/8 pseudo differential input channels

RMS noise: 11 nV @ 4.7 Hz (gain = 128)

15.5 noise-free bits @ 2.4 kHz (gain = 128)

Up to 22 noise-free bits (gain = 1)

Offset drift: ±5 nV/℃

Gain drift: ±1 ppm/℃

Specified drift over time

Automatic channel sequencer

Programmable gain (1 to 128)

Output data rate: 4.7 Hz to 4.8 kHz

Internal or external clock

Simultaneous 50 Hz/60 Hz rejection

4 general-purpose digital outputs

Power supply

AVDD: 3 V to 5.25 V

DVDD: 2.7 V to 5.25 V

Current: 4.65 mA

Temperature range: −40℃ to +105℃

28-lead TSSOP and 32-lead LFCSP packages

Interface

3-wire serial

SPI, QSPI™, MICROWIRE™, and DSP compatible

Schmitt trigger on SCLK

AD7193應(yīng)用:

PLC/DCS analog input modules

Data acquisition

Strain gage transducers

 圖1,。AD7193功能方框圖

圖2,。AD7193基本的連接框圖

圖3。AD7193典型應(yīng)用電路圖(流量計)

過程控制應(yīng)用的全編程通用模擬前端(CN0209)EVAL-CN0209-SDPZ

This circuit uses the EVAL-CN0209-SDPZ circuit board and the EVAL-SDP-CB1Z System Demonstration Platform (SDP) evaluation board. The two boards have 120-pin mating connectors, allowing for the quick setup and evaluation of the circuit’s performance. The EVAL-CN0209-SDPZ board contains the circuit to be evaluated, as described in this note, and the SDP evaluation board is used with the CN0209 evaluation software to capture the data from the EVAL-CN0209-SDPZ circuit board.

Equipment Needed

PC with a USB port and Windows® XP or Windows Vista® (32-bit) or Windows® 7 (32-bit)

EVAL-CN0209-SDPZ Circuit Evaluation Board

EVAL-SDP-CB1Z SDP Evaluation Board

CN0209 Evaluation Software

Power supply: +15 V and –15 V

RTD temperature sensor

Thermocouple

EVAL-CN0209-SDPZ評估板包括:

The EVAL-CN0209-SDPZ evaluation kit includes self-installing software on CD. The software is compatible with Windows® XP, Windows Vista (32-bits) and Windows 7 (32-bits).

The circuit shown in Figure 1 provides a fully programmable universal analog front end (AFE) for process control applications. The following inputs are supported: 2-, 3-, and 4- wire RTD configurations, thermocouple inputs with cold junction compensation, unipolar and bipolar input voltages, and 4 mA-to-20 mA inputs.

Today, many analog input modules use wire links (jumpers) to configure the customer input requirements. This requires time, knowledge, and manual intervention to configure and reconfigure the input. This circuit provides a software controllable switch to configure the modes along with a constant current source to excite the RTD. The circuit is also reconfigurable to set common-mode voltages for the thermocouple configuration. A differential amplifier is used to condition the analog input voltage range to the Σ-Δ ADC. The circuit provides industry-leading performance and cost.Because of the voltage gain provided by the AD8676 and AD8275, the design is particularly suitable for small signal inputs, all types of RTDs, or thermocouples.

The AD7193 is a 24-bit Σ-Δ ADC that can be configured to have four differential inputs or eight pseudo differential inputs. The ADuM1400 and ADuM1401provide all the necessary signal isolation between the microcontroller and the ADC. The circuit also includes standard external protection and is compliant with the IEC 61000 specifications.

EVAL-CN0209-SDPZ 主要應(yīng)用:

Energy

Motor and Power Control

Process Control & Industrial Automation

Sensors and Sensor Interface

Temperature Controllers

圖4,。過程控制應(yīng)用的全編程通用模擬前端簡化電路圖

圖5,。EVAL-CN0209-SDPZ評估板電路圖(1)

圖6。EVAL-CN0209-SDPZ評估板電路圖(2)
EVAL-CN0209-SDPZ評估板材料清單(BOM):


圖7,。EVAL-CN0209-SDPZ評估板PCB布局圖
詳情請見:
http://www.analog.com/static/imported-files/data_sheets/AD7193.pdf

http://www.analog.com/en/circuits-from-the-lab/CN0209/vc.html



本站內(nèi)容除特別聲明的原創(chuàng)文章之外,,轉(zhuǎn)載內(nèi)容只為傳遞更多信息,并不代表本網(wǎng)站贊同其觀點(diǎn),。轉(zhuǎn)載的所有的文章,、圖片、音/視頻文件等資料的版權(quán)歸版權(quán)所有權(quán)人所有,。本站采用的非本站原創(chuàng)文章及圖片等內(nèi)容無法一一聯(lián)系確認(rèn)版權(quán)者,。如涉及作品內(nèi)容、版權(quán)和其它問題,,請及時通過電子郵件或電話通知我們,以便迅速采取適當(dāng)措施,,避免給雙方造成不必要的經(jīng)濟(jì)損失,。聯(lián)系電話:010-82306118;郵箱:[email protected],。