Omron CP1H-CPU - 05-2006, Operation Manual

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xxvii
Application Precautions
5
• Check that data link tables and parameters are properly set before start-
ing operation. Not doing so may result in unexpected operation. Even if
the tables and parameters are properly set, confirm that no adverse
effects will occur in the system before running or stopping data links.
• Transfer a routing table to the CPU Unit only after confirming that no
adverse effects will be caused by restarting CPU Bus Units, which is auto-
matically done to make the new tables effective.
• The user program and parameter area data in the CPU Unit is backed up
in the built-in flash memory. The BKUP indicator will light on the front of
the CPU Unit when the backup operation 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.
• Do not turn OFF the power supply to the PLC while the Memory Cassette
is being accessed. Doing so may corrupt the data in the Memory Cas-
sette. The 7-segment LED will light to indicate writing progress while the
Memory Cassette is being accessed. Wait for the LED display to go out
before turning OFF the power supply to the PLC.
• Before replacing the battery, supply power to the CPU Unit for at least 5
minutes and then complete battery replacement within 5 minutes of turn
OFF the power supply. Memory data may be corrupted if this precaution is
not observed.
• Always use the following size wire when connecting I/O Units, Special I/O
Units, and CPU Bus Units: AWG22 to AWG18 (0.32 to 0.82 mm
2
).
• UL standards required that batteries be replaced only by experienced
technicians. Do not allow unqualified persons to replace batteries. Also,
always follow the replacement procedure provided in the manual.
• Never short-circuit the positive and negative terminals of a battery or
charge, disassemble, heat, or incinerate the battery. Do not subject the
battery to strong shocks or deform the barry by applying pressure. Doing
any of these may result in leakage, rupture, heat generation, or ignition of
the battery. Dispose of any battery that has been dropped on the floor or
otherwise subjected to excessive shock. Batteries that have been sub-
jected to shock may leak if they are used.
• Always construct external circuits so that the power to the PLC it turned
ON before the power to the control system is turned ON. 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 Out-
put 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 cir-
cuit failures, which can occur in relays, transistors, 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 maintained.)