An industrial enterprise can grow too big for efficient automation Control using traditional technology. Advances in industrial EthernetCONTROL ENGINEERING China版权所有, howeverwww.cechina.cn, can provide a solution. Using additional techniques such as smart remote I/O and peer-to-peer technology can result in better and more flexible controlCONTROL ENGINEERING China版权所有, along with a change in the way Ethernet is used.
        For one quick example of the benefits possible控制工程网版权所有, consider a site with widely scattered oil tanks. Monitoring the level in those tanks is best done with remote Ethernet-based smart I/O modules. Polling the tanks one by one to get their level works but the amount of time needed increases with the number of tanks. Smart remote modules with peer-to-peer capability can send a message to a control room if the level in a tank is lower or higher than a set point. The effect is a real-time update, done in a cost-effective way that scales easily with increasing site size.
        For end users, having Ethernet everywhere in the enterprise means the first two layers of the standard seven-layer communication model (the physical and data link layers) are the same throughout the enterprise. This eases the task of network integration and helps with network configuration and reconfiguration. It also means that one skill set can handle the entire network, reducing or eliminating the need to maintain specialized technical expertise for other networking technologies.
        Smart I/O among peers
        In the traditional master-client mode found in serial and proprietary networks控制工程网版权所有, a controller has to read input module data. It then sends data back to the output module, completing the input-output loop. Those transactions require a controller, along with wiring to and from the I/O module. This back-and-forth sequence can take extra