Mitsubishi Electric MELSEC-A series User Manual page 43

POINT
*1: Overcurrent protection
The overcurrent protection device shuts off the 5VDC and/or 24VDC circuit(s)
and stops the system if the current exceeding the specified value flows in the
circuit(s).
As this results in voltage drop, the power supply module LED turns OFF or is
dimly lit.
After that, eliminate the causes of overcurrent, e.g., insufficient current
capacity and short circuit, and then start the system.
When the current has reached the normal value, the initial start up of the
system will be performed.
*2: Overvoltage protection
The overvoltage protection shuts off the 5VDC circuit and stops the system if
the overvoltage of 5.5 to 6.5V is applied to the circuit.
This results in the power supply module LED turning OFF.
When restarting the system, power OFF and ON the input power supply, and
the initial start up of the system will be performed.
If the system is not booted and the LED remains off, this means that the
power supply module has to be replaced.
*3: Allowable momentary power failure period
The programmable controller CPU allowable momentary power failure period
varies with the power supply module used.
In case of the A1S63P power supply module, the allowable momentary
power failure period is defined as the time from when the primary side of the
stabilized power supply for supplying 24VDC to the A1S63P is turned OFF
until when the voltage (secondary side) has dropped from 24VDC to the
specified value (15.6VDC) or less.
*4: Inrush current
If the power supply module is re-powered ON right after powered OFF (within
5s), the inrush current exceeding the specified value (2ms or less) may be
generated. Therefore, make sure to re-power ON the module 5s after power
off.
When selecting a fuse or breaker for external circuit, consider the above point
as well as meltdown and detection characteristics.
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