1746-IB16 in industrial plc control system, remote i/o is a kind of high-speed local area network, in fact, it is a solution to connect the input/output devices and the central controller (cpu) in the way of bus, so as to realise the remote control of input/output devices. There are a variety of bus methods, the major companies to develop products have their own characteristics, for example, some companies use profibus-dp fieldbus, the communication medium for the shielded twisted pair, some companies use 75ω coaxial cable and catv media technology. Although the application of the media are different, but the requirements of the system is basically the same

1746-IB16 to ensure accurate and high-speed transmission of data is the basic requirements of the remote i/o. Most of the data is transferred between the rio processor (at the front end of the plc) and the rio adapter (at the remote substation), and is less than 1ms for the i/o remote substation. the plc uses a coherent communication method to serve each node, and the i/o substation is always updated within a defined time range, and calculations are made for that time range based on the user’s logical programme segment number. To ensure that information does not conflict, each node transmits on the network only within a defined time range, rather than data from several nodes being transmitted at the same time.

1746-IB16 requires strict anti-interference measures for the system. This is very important in the design and implementation phase of the project. Because the remote i/o is connected to the equipment layer, and the information transmission between the plc and the remote station is carried out in a strict time period, any interference may cause the state and action commands of the input/output devices not to be transmitted and executed correctly, thus resulting in the system malfunctioning, or even equipment accidents.