Omron CRT1 - 10-2008 Operation Manual page 20

Application Precautions
• Do not bend cables past their natural bending radius or pull on cables.
• Observe the following precautions when wiring the communications
cable.
• Separate the communications cables from the power lines or high-ten-
sion lines.
• Do not bend the communications cables past their natural bending ra-
dius.
• Do not pull on the communications cables.
• Do not place heavy objects on top of the communications cables.
• Always lay communications cable inside ducts.
• Take appropriate measures to ensure that the specified power with the
rated voltage and frequency is supplied. Be particularly careful in places
where the power supply is unstable. An incorrect power supply may result
in malfunction.
• Install external breakers and take other safety measures against short-cir-
cuiting in external wiring. Insufficient safety measures against short-cir-
cuiting may result in burning.
• Fail-safe measures must be taken by the customer to ensure safety in the
event of incorrect, missing, or abnormal signals caused by broken signal
lines, momentary power interruptions, or other causes.
• Confirm voltage specifications when wiring communications, the power
supply, and I/O crossovers. Incorrect wiring may result in malfunction.
• Do not apply voltages or connect loads to the Output Units in excess of
the maximum switching capacity. Excess voltage or loads may result in
burning.
• Do not apply voltages to the Input Units in excess of the rated input volt-
age. Excess voltages may result in burning.
• After replacing Units, resume operation only after transferring to the new
CPU Unit and/or Special I/O Units the contents of the DM Area, HR Area,
and other data required for resuming operation. Not doing so may result in
an unexpected operation.
• Check the user program for proper execution before actually running it on
the Unit. Not checking the program may result in unexpected operation.
• Check all wiring and switch settings to be sure they are correct.
• Always turn OFF the power supply to the PLC and Slave Units before
attempting any of the following. Not turning OFF the power supply may
result in malfunction or electric shock.
• Removing or attaching terminal blocks to Slave Units and Expansion
Units
• Connecting or removing terminal blocks
• Replacing parts
• Setting the DIP Switches and Rotary Switches
• Connecting cables or wiring the system.
• Confirm that no adverse effect will occur in the system before attempting
any of the following. Not doing so may result in an unexpected operation.
• Changing the operating mode of the PLC
• Force-setting/force-resetting any bit in memory
• Changing the present value of any word or any set value in memory
from the user program
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