基于微控制器的隔离变送器的设计

DC 4～20 mA是工业常用的信号传输形式,与电压信号传输相比,其抗干扰能力强。由于工业现场环境恶劣,若现场传感器、一次仪表或变送器直接与二次仪表、PLC或上位机相连,则很容易使系统受到干扰,因此最好采用无电气连接的隔离器连接。介绍了基于微控制器的隔离变送器的设计方案,该设计以嵌入式混合信号微处理器C8051F350作为核心,充分利用内部AD功能,采用光电隔离器件实现信号传递的隔离。在设计电路简化的基础上,降低了成本,减小了体积,已在工业现场得到应用。

Realization of isolation transmitter based on MCU

DC 4-20 mA signal transmission is commonly used in the form of industry.It has strong interference ability when compared with the voltage signal transmission.For the bad environment,the system subject may easy to be interferenced when the on-site sensors,one instrument or transmitter directly connected with the secondary instrument PLC or host computer,and so it is better to use no electrical connections isolator.The isolation of microcontroller-based transmitter design was described.Embedded mixed-signal microprocessor C8051F350 was used as a core,and to make full use of the internal AD function,optical isolation devices were used to achieve isolation of signal transduction.Costs and volume were reduced based on the design of simple circuit.And it has already been applied in the industry.