Omron CJ2 CPU UNIT SOFTWARE User Manual page 30

Execute online edit only after confirming that no adverse effects will be
caused by extending the cycle time. Otherwise, the input signals may not be
readable.
Confirm safety at the destination node before transferring a program, PLC
Setup, I/O tables, I/O memory contents, or parameters to another node or
changing contents of the any of these items. Transferring or changing data
can result in unexpected system operation.
The CJ2 CPU Units automatically back up the user program and parameter
data to flash memory when these are written to the CPU Unit. I/O memory
including the DM, EM, and Holding Areas), however, is not written to flash
memory.
The DM, EM, and Holding Areas can be held during power interruptions with
a battery. If there is a battery error, the contents of these areas may not be
accurate after a power interruption. If the contents of the DM, EM, and Hold-
ing Areas are used to control external outputs, prevent inappropriate outputs
from being made whenever the Battery Error Flag (A402.04) is ON.
Tighten the terminal screws on the AC Power Supply Unit to the torque spec-
ified in the operation manual. The loose screws may result in burning or mal-
function.
Do not touch the Power Supply Unit when power is being supplied or immedi-
ately after the power supply is turned OFF. The Power Supply Unit will be hot
and you may be burned.
When connecting a personal computer or other peripheral device to a PLC to
which a non-insulated Power Supply Unit (CJ1W-PD022) is mounted, either
ground the 0 V side of the external power supply or do not ground the exter-
nal power supply at all ground. A short-circuit will occur in the external power
supply if incorrect grounding methods are used. Never ground the 24 V side,
as shown below.
Wiring in Which the 24-V Power Supply Will Short
Non-insulated
DC power supply
24 V
0 V
Power Supply
FG
Unit
24
Caution
Peripheral
cable
0 V
Peripheral device (e.g.,
CPU Unit
personal computer)
CJ2 CPU Unit Software User's Manual