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7.7.3 Discharge control answer-back
It is necessary for the MCU to know if the command output has been obeyed correctly. Hence, an
input is provided to signal the “status” of the discharge control system. The input could be from e.g.
a micro switch on the overboard valve. The answer-back is shown on the display as “POS” and
status is shown as “O” (open) or “C” (closed).
If the MCU is in “Control” mode and the command and status indications do not agree, after 2 min,
an alarm will be triggered to indicate a fault. The overboard valve command will then be “CLOSE”.
The discharge rate and total oil discharged calculations are performed once the status is open. This
means that if the overboard valve is opened even when the command signal is to close the valve,
then the normal calculation will be carried out and the amount of oil discharged will be recorded.
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