Omron CJ Series Operation Manual page 22

Precautions for Safe Use
• Do not apply voltages or connect loads to the Output Units or slaves in excess of the maximum rat-
ings.
• Surge current occurs when the power supply is turned ON. When selecting fuses or breakers for
external circuits, consider the above precaution and allow sufficient margin in shut-off performance.
Refer to the relevant manuals for surge current specifications. Refer to the NJ-series CPU Unit Hard-
ware User's Manual (Cat. No. W500) for surge current specifications.
• If the full dielectric strength voltage is applied or turned OFF using the switch on the tester, the gener-
ated impulse voltage may damage the Power Supply Unit. Use the adjustment on the tester to grad-
ually increase and decrease the voltage.
• Apply the voltage between the Power Supply Unit's L1 or L2 terminal and the GR terminal when test-
ing insulation and dielectric strength.
• Do not supply AC power from an inverter or other device with a square-wave output. Internal temper-
ature rise may result in smoking or burning. Always input a sinusoidal wave with the frequency that is
given in the NJ-series CPU Unit Hardware User's Manual (Cat. No. W500).
• Install external breakers and take other safety measures against short-circuiting in external wiring.
Turning ON the Power Supply
• It takes up to approximately 10 to 20 s to enter RUN mode after the power is turned ON. During that
time, outputs will be OFF or will be the values specified in the Unit or slave settings, and external
communications cannot be performed. Use the RUN output on the Power Supply Unit, for example,
to implement fail-safe circuits so that external devices do not operate incorrectly.
• Configure the external circuits so that the power supply to the control system turns ON only after the
power supply to the Controller has turned ON. If the power supply to the Controller is turned ON after
the control power supply, temporary errors may result in incorrect control system signals because the
output terminals on Output Units may momentarily turn ON when power supply is turned ON to the
Controller.
• If you transfer data from a backup file on an SD Memory Card to the Controller when the power sup-
ply is turned ON, properly select the data groups to transfer. If the data for an unintended data group
is transferred to the Controller, it may cause the equipment to operate unpredictably.
Actual Operation
• Check the user program, data, and parameter settings for proper execution before you use them for
actual operation.
Turning OFF the Power Supply
• Never turn OFF the power supply to the Controller when the BUSY indicator is flashing. While the
BUSY indicator is lit, the user program and settings in the CPU Unit are being backed up in the built-
in non-volatile memory. This data will not be backed up correctly if the power supply is turned OFF.
Also, a major fault level Controller error will occur the next time you start operation, and operation will
stop.
• Do not turn OFF the power supply or remove the SD Memory Card while SD Memory Card access is
in progress (i.e., while the SD BUSY indicator flashes). Data may become corrupted, and the Control-
ler will not operate correctly if it uses corrupted data. To remove the SD Memory Card from the CPU
Unit while the power supply is ON, press the SD Memory Card power supply switch and wait for the
SD BUSY indicator to turn OFF before you remove the SD Memory Card.
• Do not disconnect the cable or turn OFF the power supply to the Controller when downloading data
or the user program from Support Software.
• Always turn OFF the power supply to the Controller before you attempt any of the following.
• Mounting or removing I/O Units or the CPU Unit
• Assembling the Units
• Setting DIP switches or rotary switches
20 CJ-series Analog I/O Units Operation Manual for NJ-series CPU Unit(W498)