基于新型通信方法的模拟量采集板卡的设计与实现

摘要

For different analog-signals, special acquisition modules are expanded in PLC control system.If current multi-signal-types analog acquisition modnle is used, PLC serial port (485/232) and communication protocol such as MODBUS are needed.The both methods are complex and of poor price performance ratio.In order to slove the problem, a multi-functional analog acquisition card was developed, in which only two PLC digital input-ports instead of PLC communication interface were used.The results indicate that the card can real-timely acquire temperature, standard current and voltage, also can communicate with any type PLC and meet correspending requirements of EFT testament.This design is universal and has high price performance ratio.The card has been used in PLC control system reliably.%对于不同的模拟量输入信号,PLC控制系统需要扩展专用的采集模块;现有的多功能模拟量采集模块与PLC通讯通常采用MODBUS协议,并占用PLC有限的通讯接口.两种方案实现复杂,性价比差.为此,开发了一款不占用PLC现有通讯接口、仅利用2个PLC数字输入口进行通信的多功能模拟量采集板卡.研究结果表明,该板卡能够实时采集温度、标准电流、电压信号,并能和任何类型PLC实现通信,通用性强,性价比高,满足电快速瞬变脉冲群试验相应要求,已经可靠地应用于PLC控制系统中.