摘要
设计一种应用于可编程逻辑控制器(PLC)的数据采集模块。模块可以将热电阻或热电偶的温度信号、电流电压信号转变成数字量后上传至PLC。硬件电路由信号调理电路、信号放大电路、A/D转换电路、滤波电路等组成。模块可以通过并行接口的通讯方式,使用请求半字节输出的方法与欧姆龙CPM2AH控制器通讯,由5位开关量的时序变化将数据传送给PLC。通过很少的开关量输入点,PLC就可以完成对多路模拟信号的采集,有效地节约了控制成本。除并行通讯方式外,模块还设计了RS-485串行接口的方式来完成与PLC的通讯。系统采用分段线性化算法进行校正处理,利用MATLAB软件得到最小二乘法拟合曲线,使传感器的全温度范围精度优于0.1℃。
This paper introduces a data acquisition module which supports in programmable logic controller （PLC）.The module can collect the temperature signal of thermo resistant or thermocouple,voltage signal and current signal into digital quantity,then upload them to the PLC.The composition of the hardware circuit includes the acquisition circuit,signal amplification circuit, A/D conversion circuit,filter circuit.The module provided the method and programmer which communicates with OMRON CPM2AH controller through parallel the half of byte requestion in 5 byte switch quantity output time sequence.Through the little switch input point, PLC can complete the multichannel analog signal acquisition, effectively reduce the cost of control system.In addition to parallel communication,the module also design the RS-485 serial interface method to communicate with PLC.
出处
《工业控制计算机》
2013年第1期88-90,共3页
Industrial Control Computer
