Remote IO? What is the difference from regular IO?
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Is it just the distance? What are the requirements in terms of signal acquisition and processing technology?
Remote IO generally involves placing the IO acquisition cards at the site, where they exchange data with the controller through communication means. It represents a transitional form between traditional DCS systems (where the controller and IO devices are located close to each other within cabinets in the control room) and FCS systems (where all control functions are placed at the field level). The main advantages are: 1. Saves cables 2. Reduces wiring costs 3. Decreases the size of the control room. Disadvantages: 1. Requires high manufacturing standards and the ability to adapt to field conditions 2. Cannot be maintained centrally
With the development of digital communication technology, IPC hosts can utilize remote I/O technology to communicate digitally with field devices. Compared to analog communication, digital communication has the following significant advantages: ① It has strong resistance to interference; especially during long-distance transmission, repeaters can regenerate the signal to eliminate noise accumulation. ②Digital signals are easy to generate, store, and exchange, and are convenient for connecting to computers. ③It facilitates the implementation of anti-interference coding and error control. The remote I/O solution utilizes advanced and reliable industrial-grade front-end modules. The front-end modules are installed on-site, with a separately configured network interface module facilitating data communication between the host and each front-end module. The system adopts a master-slave network transmission structure and communicates through an RS_485 interface, offering advantages such as two-way information transmission and reduced wiring costs.
Remote IO is located close to the field devices, which saves on cables needed for on-site connections; shorter cable distances result in less signal attenuation. Remote IO transmits signals to the CPU via a single communication cable, which can affect communication speed and increase the number of potential failure points. Remote IO offers flexible installation options, while local IO is usually connected through backplanes or racks, enabling faster communication speeds and easier maintenance
Remote IO also has important applications in signal acquisition and communication in hazardous areas; it not only saves costs but also helps to isolate hazards and reduce risks.