Omron CJ2 User Manual page 30

• The user program and parameter area data in the CJ2 CPU Units are backed up in the built-in
flash memory. The BKUP indicator will light on the front of the CPU Unit when the backup opera-
tion is in progress. Do not turn OFF the power supply to the CPU Unit when the BKUP indicator is
lit. The data will not be backed up if power is turned OFF.
• Check the user program and Unit parameter settings for proper execution before actually running
them on the Unit. Not checking the program and parameter settings may result in an unexpected
operation.
• When setting a Special I/O Unit or CPU Bus Unit in the I/O tables, carefully check the safety of the
devices at the connection target before restarting the Unit.
• A CS1 or CJ1 CPU Unit program file (.OBJ) cannot be transferred directly to a CJ2 CPU Unit
using a Memory Card. It must first be converted for use with a CJ2 CPU Unit using the CX-Pro-
grammer.
External Circuits
• Interlock circuits, limit circuits, and similar safety measures in external circuits (i.e., not in the Pro-
grammable Controller) must be provided by the customer.
• Always turn ON power to the PLC before turning ON power to the control system. If the PLC
power supply is turned ON after the control power supply, temporary errors may result in control
system signals because the output terminals on DC Output Units and other Units will momentarily
turn ON when power is turned ON to the PLC.
• Fail-safe measures must be taken by the customer to ensure safety in the event that outputs from
Output Units remain ON as a result of internal circuit failures, which can occur in relays, transis-
tors, and other elements.
• If the I/O Hold Bit is turned ON, the outputs from the PLC will not be turned OFF and will maintain
their previous status when the PLC is switched from RUN or MONITOR mode to PROGRAM
mode. Make sure that the external loads will not produce dangerous conditions when this occurs.
(When operation stops for a fatal error, including those produced with the FALS(007) instruction,
all outputs from Output Unit will be turned OFF and only the internal output status will be main-
tained.)
• Install external breakers and take other safety measures against short-circuiting in external wiring.
Insufficient safety measures against short-circuiting may result in burning.
• Dispose of the product and batteries according to local ordinances as they apply.
• Do not turn OFF the power supply to the PLC when reading or writing a Memory Card. Also, do
not remove the Memory Card when the BUSY indicator is lit. Doing so may make the Memory
Card unusable.
• To remove a Memory Card, first press the memory card power supply switch and then wait for the
BUSY indicator to go out before removing the Memory Card.
24 CJ2 CPU Unit Hardware User's Manual