I have a really stupid question: the signal that MCC sends to the DCS via intermediate relays to indicate preparation is DI. What about starting and stopping?
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For the stop and start commands sent from MCC to DCS via a relay, are they DI or DO? It is now remotely controlled via the control box; the relay inside should be activated and stopped by the DCS! That one is DO! So I want to ask how exactly one determines DI, DO, as well as running and stopping? ? ? More details! Thank you!
From the motor to the control system, when it is in local mode, the indication from the MCC sends a DI signal to the DCS; on the screen, only operation status and stop status are displayed； When it is in remote mode, the control system sends DO signals to the MCC to control operation and shutdown; simultaneously, the MCC sends DI signals to the DCS to feedback the status of operation and shutdown. The operation and stop DCS control signals and display signals are two separate sets.
How are DI and DO distinguished? Those that go into the DCS are DI, while those that come out of the DCS are DO. For example, when the DCS sends signals to the MCC to control the start and stop of a pump, this is considered DO; whereas signals from the MCC regarding the pump’s operation or any faults are DI signals. Since pumps are devices that operate under high voltage, they cannot be controlled directly by the DCS; instead, they must be controlled through the electrical Main Control Center (MCC).
Regardless of the DI and DO signals on the MCC side, for a DCS, the operation and stop signals are both DI. Generally, DCS signals do not go directly to the field; instead, they go to the MCC to control whether the contactors are powered or not. These are DO signals. The operation and stop states are represented by DI signals, while the start and stop commands are DO signals
I means IN, entering; O means OUT, exiting. You can understand it this way: look at who is proactive in terms of the signal, who holds the initiative in that signal. If it is a signal generated by a motor that is sent to the DCS, it is all DI. If the signals generated by DCS are sent to the motor, they are all DOs. Therefore, start/stop operations are represented by DOs, while various states are represented by DI’s. Got it?
Oh my God! Can you stop asking questions like that?
Thank you all... May I understand it as... the motor preparation signal and operation signal are DI, while the start/stop signal is DO? I’m truly sorry; I majored in economic law before switching to electrical instrumentation, so I’m not very familiar with many of the basic concepts! ! ! ! I’m really sorry!
I admire the courage of the original poster – a humanities student who decided to switch to a technical field and still persists in researching issues with such dedication. Give him a thumbs up
The feedback signals sent from the electrical system to the DCS are known as DI; these are mainly operation signals and fault signals, and they are used solely to display the current operating status of the motor on the DCS monitor. On the other hand, the signals that the DCS sends to the MCC to initiate operations are called DO; these signals are used to enable remote starting or stopping of the motor via the DCS monitoring interface, and such commands are issued by the DCS
Thank you all! Thank you so much! ! ! I’ve rushed to learn the basics of electrical work, and now I understand what I/O means! Thank you so much... but could someone please explain in simpler terms the difference between dry contacts and wet contacts, as well as active and passive components? Easy to understand!