ADI CN0292工业级四路数据采集系统方案

ADI公司的CN0292是全隔离的工业级四路数据采集系统,主要采用AD7176-2高分辨率24位Sigma-Delta ADC,AD8476全差分输入和输出放大器, ADA4096-4四路运算出放大器, ADA4898-1超低功耗运算放大器, ADG1204模拟复接器以及ADP1720低压降线性稳压器,主要用在仪表,PLC/分布控制系统,测试和测量.本文介绍了工业级四路数据采集系统主要电路描述,电路框图, 测试建立功能框图,详细电路图,材料清单和PCB设计文件.
The circuit in Figure 1 is a completely isolated, robust, industrial, 4-channel data acquisition system that provides 16-bit, noise free code resolution and an automatic channel switching rate of up to 42 kSPS. The channel to channel crosstalk at 42 kSPS switching is less than 15 ppm FS (less than −90 dB) because of the unique selection of fast settling components in the multiplexed signal chain. The circuit acquires and digitizes standard industrial signal levels of ±5 V, ±10 V, 0 V to 10 V, and 0 mA to 20 mA. The input buffers also provide overvoltage protection, thereby eliminating the leakage errors associated with conventional Schottky diode protection circuits.
Applications for the circuit include process control (PLC/DCS modules), battery testing, scientific multichannel instrumentation, and chromatography.

图1. CN0292四路数据采集系统功能框图

图2.EVAL-CN0292-SDZ评估板和EVAL-SDP-CB1Z SDP的连接图
CN0292四路数据采集系统应用: 
Instrumentation
Programmable Logic Controllers/ Distributed Control Systems
Electronic Test & Measurement
工业级四路数据采集系统主要电路描述
Signal Path
Four channels of input signals are buffered by the ADA4096-4, a quad, rail-to-rail, input/output op amp featuring overvoltage protection against phase reversal or latch-up for inputs of up to 32 V above or below the ±15 V supply rails, which eliminates the need for additional overvoltage protection circuitry.
The inputs are designed for typical low frequency, industrial signals of ±10 V. The input buffers provide a high impedance to the sources and isolate the inpu...