【摘要】 针对Modbus协议相对于如局域控制网总线时间响应差的缺点,提出一种基于Modbus协议的变频控制器的设计方案.根据VFD-L系列变频器Modbus具有Network ASCⅡ通讯模式的要求,设计RS-485通讯电路和通讯程序,并且在RS-485通讯电路的设计中重点考虑对干扰的屏蔽.系统以S3C44B0X芯片为核心,使用μC/OS-Ⅱ操作系统,配合S3C44B0X处理器构成软硬件环境,以增强Modbus协议在应用中的实时性能.更多还原

【Abstract】 A designing scheme of controller for variable frequency converter(VFC) based on Modbus protocol is presented since time response of Modbus protocol is weak compared with controller area network-BUS(CAN-bus).The RS-485 communication circuit and program is designed with an emphasis on how to shield the disturbing signal,according to that Modbus protocol for VFD-L series Inverter is need of Network ASCⅡ communication mode.The system provides a hardware-software environment in order to enhance the real-time performance of Modbus protocol in the practical application,in which S3C44B0X is as the kernel,μC/OS-Ⅱ as the operating system,and S3C44B0X processor is combined.更多还原