基于S7—200PLC自由通讯口方式的通讯可靠性讨论及设计

Discussion and design of communication reliability based on S7-200 PLC's free communication model

针对在自由通讯口方式下接收数据可能遇到的一些可靠性问题 ,提出设置静止线定时器和接收器 ,并采用工程CRC校验的方法加以解决 .使用该方法设计出的通讯程序可靠性高、潜在故障少 ,可保证高质量的数据块通讯的要求 .工程应用实例说明 ,该方法的使用还可节省硬件成本 ,避免造成资源浪费 .

In order to solve some possible existing problems of receiving datum in free communication model,the methods of setting static line timer and static line receiver and using the engineering CRC verification have been expounded.The communication program which uses the given method has the characteristics of high reliability and less latent faults,and it could guarantee the high quality data communication.The realistic engineering application illustrated that the using of this method can also reduce the cost of hardware and avoid the lost of hardware resource.