Remote I/O
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What is remote I/O? What is different about it compared to regular I/O?
IO modules that can be placed at a distance and connected via bus or fiber optic, Ethernet cables.
Was his control done on-site?
The calculation still needs to be carried out through the controller, so it depends on where the controller is located
The remote IO I’ve seen is just regular IO; since some devices are located far away, it’s too costly to run cables from the site to the control room, and maintenance becomes difficult. Therefore, the IO cards are placed at the site (in some cases, an IO substation is set up there), and then via a bus—using fiber optics for long distances—they are connected to the control room where they join other IOs inside the controller.
It’s originally just ordinary IO; it’s just the method of signal transmission that differs.
It’s just that the communication method, that is, the type of bus used, is different; everything else should be the same.
It can be said that the emergence of buses has facilitated the implementation of remote IO, right?
Taking the Yokogawa CS system as an example, the RIO (i.e., remote I/O) can be located separately from the FCU (field control unit). The process nodes of the RIO structure can be located on-site, while the control unit is placed in a control room; the length of the RIO bus can reach 20 kilometers. The main advantage of doing this is to reduce cable costs, and it is beneficial for a large-scale DCS control system.
The concept of remote IO refers to the situation where the IO is located at a considerable distance from the controller, usually more than 800 meters. Because the distance over which electrical signals can be transmitted is limited (depending on the quality of the cable and interference from the surrounding environment). Remote IO is also part of the system; it’s just located at a greater distance from the controller. It has nothing to do with the others. It’s just that ordinary IO increases the distance over which signals can be transmitted by converting light and electrical signals (different devices are used by various manufacturers, but the principle remains the same).
For long distances, an adapter is required; distances over 250 meters are considered long distances. For short distances, it can be connected directly to the FTA terminal board without the need for an adapter
When remote IO is installed on-site, are there any requirements regarding explosion protection? Can it be placed in an explosion-proof environment?