All channels of the DCS DI card are fully conductive
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An alarm is triggered within 1 second as soon as a record is checked. This DI card contains signals related to the operation of pumps, as well as fault signals. I would like to ask: if 220VAC electricity gets into this DI card, could it cause a complete failure? The DI card wiring uses a 24V common negative terminal
DI cards generally receive mechanical pump signals in dry contact form; when these signals are transmitted serially, it can cause the card to be damaged. If there is an isolation circuit board before the DI card, that board will also get damaged.
But mine doesn’t have any card burning or anything like that
The DI card board has been burned once; it is used to enable the equipment’s PLC to receive operating signals from the MCC. Reason: There was a wrong wiring connection at the MCC; the 24 V wire from DI was connected to the 220V terminal of the drawer cabinet. As soon as the electrical control circuit was powered on, the voltage surged to 220 volts, causing the circuit board to burn out. Later, a rule was established: whenever a signal comes from MCC, regardless of whether a relay is installed on the electrical side or not, a relay isolation must be provided on the instrument control system side (including all PLCs).