NAiS FP Series Hardware Manual page 4

Power supply
sequence
Before turning
ON the power
D Have the power supply sequence such that
the power supply of the FP0 control unit turns
OFF before the power supply for I/O.
D If the power supply for I/O is turned OFF
before the power supply of FP0 control unit,
the FP0 control unit will detect the input
fluctuations and may begin an unscheduled
operation.
When turning ON the power for the first time, be sure to take the
precautions given below.
D When carrying out assembly, check to make
sure that there are no scraps of wiring,
particularly conductive fragments, adhering to
the unit.
D Verify that the power supply wiring, I/O wiring,
and power supply voltage are all correct.
D Sufficiently tighten the installation screws and
terminal screws.
D Set the mode switch to PROG. mode.