描述
产品概述
NI-9425是美国国家仪器（NI）推出的C系列32通道数字输入模块，专为工业环境设计，支持24 V逻辑电平输入，采用Sinking（sinking input）架构，提供通道间及对地隔离保护，适用于高可靠性数字信号采集场景（如工业开关状态监测、设备控制反馈）。
核心参数与功能
输入特性
-通道配置：32通道Sinking输入，每通道兼容24 V工业逻辑电平；
-响应速度：信号延迟典型值7µs；
-隔离性能：
-通道间隔离：250 V RMS（CAT II等级）；
-对地隔离：60 V DC（CAT I等级，DSUB接口版本）。
物理接口与扩展
-接线方式：支持DSUB连接器或弹簧端子（可选）；
-兼容平台：
-适用于CompactRIO、CompactDAQ等NI嵌入式系统；
-不支持在CompactDAQ机箱中执行计数器操作。
硬件设计
-电路架构：
-每4通道共享一个隔离组，简化信号调理电路；
-内部采用比较器（如ADUM1401隔离芯片）及三极管驱动电路（如ST意法半导体元件）；
-生产信息：2014年量产，匈牙利生产。
功能特点
工业兼容性：
-直接接入工业开关、传感器等设备，耐受宽范围电压波动；
-支持漏极/源极功能，增强输入信号适应性。
抗干扰设计：
-隔离保护降低共模噪声影响，适用于电磁复杂环境；
-信号调理电路无FPGA/CPLD处理层，减少延迟。
软件集成：
-通过LabVIEW FPGA实现自定义高速数字通信协议或脉冲生成（结合CompactRIO使用）；
-支持NI-DAQmx驱动及TestStand自动化测试框架。
Product Overview
NI-9425 is a C-series 32-channel digital input module launched by National Instruments(NI).It is specially designed for industrial environments and supports 24 V logic level input.It adopts a Sinking(sinking input)architecture to provide channel-to-channel and ground isolation protection.It is suitable for high-reliability digital signal acquisition scenarios(such as industrial switch status monitoring,equipment control feedback).
Core parameters and functions
Input Features
-Channel configuration:32 channels of Sinking input,each channel is compatible with 24 V industrial logic levels;
-Response speed:signal delay is 7µs typical;
-Isolation performance:
-Channel Isolation:250 V RMS(CAT II Level);
-Ground isolation:60 V DC(CAT I level,DSUB interface version).
Physical interfaces and extensions
-Wiring method:Supports DSUB connector or spring terminal(optional);
-Compatible platform:
-Suitable for NI embedded systems such as CompactRIO and CompactDAQ;
-Execution of counter operations in CompactDAQ chassis is not supported.
Hardware design
-Circuit architecture:
-Share an isolation group every 4 channels to simplify signal conditioning circuit;
-Use comparators(such as ADUM1401 isolation chip)and transistor drive circuits(such as ST STMicroelectronics components);
-Production information:mass production in 2014,produced in Hungary.
Functional Features
Industrial Compatibility:
-Directly connect to industrial switches,sensors and other equipment to withstand wide range of voltage fluctuations;
-Support drain/source function to enhance input signal adaptability.
Anti-interference design:
-Isolation protection reduces the impact of common mode noise,suitable for complex electromagnetic environments;
-The signal conditioning circuit has no FPGA/CPLD processing layer,reducing delay.
Software Integration:
-Implement custom high-speed digital communication protocol or pulse generation through LabVIEW FPGA(used in combination with CompactRIO);
-Supports NI-DAQmx driver and TestStand automation testing framework.
