Is the power supply for the DCS in the project currently implemented according to the diagram in the SH specifications?
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I’ve studied this diagram; guys, please take a look and let me know if my understanding is correct. 1. Under normal conditions, the UPS connects to the mains power to charge the batteries, with the battery output and the bypass output feeding into the static switch; when the bypass mains power is lost, the system switches to using battery power for supply. 2. Distribution cabinets 1 and 2 are connected to two redundant power supply modules of the DCS system. When distribution cabinet 2 (connected to mains power) loses power, the redundant power supply modules switch to supply power to distribution cabinet 1. 3. In the diagram, the servers are connected to two power sources via static switches. Is this really how it’s done in actual projects? Those static switches seem quite expensive, costing around 2-3 watts each. Why not connect the server directly to the UPS output? Under normal circumstances, the UPS uses mains power; when the mains power is unavailable, it switches to battery power, and it also has a static switch inside.
Not all DCS manufacturers have server cabinets; if there are only a few cabinets, an AC power distribution cabinet is not necessary. If there are many cabinets, an AC power distribution cabinet is required.
So if there are few cabinets and no dedicated power distribution cabinets, but there are still two power supply routes – one from the UPS and one from the mains – which are fed to the two redundant power cards in the DCS system, is that correct?
Yes, that’s how the power supply inputs for the central control system and HollySys work.
No. 1. The UPS bypass switch is used for UPS maintenance; it is closed only during maintenance, and nowadays all UPS units are online type. 2. The power supply module is always running; there is no switching on or off. Look, isn’t the output connected to one circuit? 3. Power conversion switches are not expensive; the server is connected directly to the UPS. If the UPS fails, how can the server continue to operate? The switching time of the power conversion switch is sufficient to allow the server to keep running.