Distributed IO compliance
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Dear sea friends, let’s discuss whether distributed IO meets the design specifications, especially given that in areas with explosion hazards, cabinet rooms are required to be explosion-proof. Also, whether it complies with regulations to place IOs in the power distribution room is open for discussion.
If it is turned on on-site, it is considered a violation
HG/T 20508-2014 Specifications for Control Room Design 4 Field Cabinet Rooms 4.0.7 For field cabinet rooms in chemical plants where there is a risk of explosion, an explosion-resistant structural design shall be adopted. Based on the practical experience of chemical engineering companies, the blast-resistant cabinet rooms on site have the following advantages: 1. Not only are there many people in these on-site cabinet rooms during the commissioning and trial operation phases, but there is also a small number of people present there throughout normal production periods; therefore, the blast-resistant structure of such cabinet rooms provides better protection for human safety ； 2 The control system and safety system equipment located in the on-site cabinet room are responsible for controlling the associated devices as well as ensuring safety interlocks; the explosion-resistant structure of this cabinet room allows the devices to shut down safely and in an orderly manner even in the event of explosion shock waves ； The main concern is the statement that \"the on-site cabinet room of the blast-resistant structure can still ensure the orderly and safe shutdown of the equipment in the event of an explosion shock wave,\" and distributed IO does not meet this requirement
Hollyland and Zhejiang University Control System seem to offer similar products. Are there any clear standard requirements for such systems? This is especially true when it comes to upgrading existing systems; the investment required for such systems is relatively low
Cables are not needed; the price of the modules is too high. It’s suitable for factories with many connection points and good operating conditions
It depends on the cable length; if there are many points, a longer cable still has advantages. The environmental aspect is indeed something that needs to be taken into consideration
With the wind and rain at the site, resistance to violence or explosions isn’t taken into account, so it’s rather risky to use it there. We’re mainly considering whether we can find a location near, but outside the blast area, to set up another blast-resistant cabinet room :(If it’s not possible to locate the cabinet room nearby, and given the many processes involved in some combined devices, it’s true that the cables required to connect everything to a single central control room tend to be quite long!) ! ! Another point is that this Distributed Control System, or “DCS”, can only be centralized; if it isn’t distributedly arranged, it loses its very purpose of being both decentralized and centralized!
Then why not just use bus technology? But it depends on your number of points and the length of the cable; if there are few points, it is not recommended to use it, as FCS is relatively about twice as expensive as DCS, such as the OCS system launched by ABB nowadays. If there are few points, just use an on-site positive-pressure explosion-proof cabinet.
Why is no one willing to use bus systems?