YOKOGAWA F3LR02-0N, User Manual

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A4-16
IM 34M06H45-01E 7th Edition : Aug.30, 2019-00
A4.6 Precautions When Applying Power
When turning on the power supply to the main unit and subunits, follow the sequence
below.
First confirm that the main unit and all subunits are turned off. Then turn on the power
supply to the main unit and the subunits simultaneously*, or turn on all subunits before
turning on the main unit.
A program starts execution when the main unit is turned on, regardless of whether
subunits are switched on. In situations where the powering sequence described above is
not adhered to, you should write your application so that it checks the status of subunits
using the special registers as listed on the next page. In this case, do not switch off and
switch on the main unit, or restart the CPU module, while a subunit is switched on.
*
: By “simultaneously”, we mean, for instance, a system whereby a single switch turns on the power to the entire system.
Note
If you have switched off the main unit, ensure that all subunits are switched off before
switching on the main unit. If you switch off and on the main unit while a subunit is
switched on, some modules in the subunit may not be recognized correctly by the CPU
module in the main unit.