Omron NJ501-1400 User Manual page 21

Turning ON the Power Supply
• It takes up to approximately 10 to 20 s to enter RUN mode after the power is turned ON. The outputs
during this time behave according to the slave or Unit specifications. Use the RUN output on the
Power Supply Unit, for example, to implement fail-safe circuits so that external devices do not oper-
ate 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.
• In the CPU Unit with unit version 1.05 or earlier, never turn OFF the power supply to the Controller
until RUN mode is entered after the power is turned ON. If the power supply is turned OFF, a Battery-
backup Memory Check Error may occur at next time you start operation. If a Battery-backup Memory
Check Error occurs, the variables retained are set to their initial values and the Holding, DM and EM
Areas in memory used for CJ-series Units are cleared to all zeros. If you want to resume the opera-
tion, reload the correct data for the variables retained and CJ-series Unit memory, as required.
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
• Connecting cables or wiring the system
• Connecting or disconnecting the connectors
The Power Supply Unit may continue to supply power to the rest of the Controller for a few seconds
after the power supply turns OFF. The PWR indicator is lit during this time. Confirm that the PWR
indicator is not lit before you perform any of the above.
NJ-series CPU Unit Hardware User's Manual (W500)
Precautions for Safe Use
19