May I ask a question? Do your cabinets receive the 220V DI signals via the electrical MCC cabinet?
Thread Content
May I ask a question? Do your cabinets receive the 220V DI signals via the electrical MCC cabinet?
No, ours uses DI card components to connect to the dry contacts of electrical relays
For the DI signals, we did not receive them from the 220V MCC cabinet; whereas the DO signals are directly connected in the MCC circuit.
This post was last edited by hanhaigang128 on 2023-11-12 at 15:14. The DI from our MCC is a dry contact, and it is isolated using relays on the DCS side； Generally, the DI signals coming from the MCC are the auxiliary contacts of contactors, faults in frequency converters, and operational DO outputs (sometimes, the fault signals from frequency converters and operational outputs are transmitted via 220VAC relays). Under normal circumstances, these are dry contacts that do not carry electricity; however, in cases where contactors or frequency converters (relays) are damaged, high-voltage currents such as 220VAC or other voltage levels may appear in the DI signals. Isolation is achieved using 24VDC relays on the instrument cabinet side to protect the I/O cards.