Application Precautions - Omron DEVICENET Operation Manual

Application Precautions

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Application Precautions

• 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.
• Emergency stop circuits, interlock circuits, limit circuits, and similar safety
measures must be provided in external control circuits (i.e., not in the Pro-
grammable Controller).
• Use the power supplies specified in the operation manuals.
• If the system is installed at a site with poor power supply conditions, take
appropriate measures to ensure that the power supply remains within the
rated voltage and frequency specifications.
• 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.
• Always ground the system to 100 Ω or less when installing the system to
protect against electrical shock.
• Make sure that the Unit is securely mounted, either to the DIN Track or by
screws.
• Always turn OFF the communications power supply and the power sup-
plies to the PLC and Slaves before attempting any of the following.
• Mounting or removing a Unit such as an I/O Unit, Power Supply Unit,
CPU Unit, Memory Cassette, or Master Unit.
• Connecting or disconnecting Remote I/O Terminal circuits.
• Assembling any devices or racks.
• Setting DIP switches or rotary switches.
• Connecting or wiring cables.
• Connecting or disconnecting connectors.
• Do not attempt to disassemble, repair, or modify any Units.
• Make sure that the terminal block screws are tightened to the torque
specified in the relevant manuals. Loose screws may result in fire, mal-
function, or damage.
• Confirm that no adverse effect will occur in the system before attempting
any of the following.
• Changing the operating mode of the PLC (including the operating
mode setting when the power is turned ON)
• Force-setting/force-resetting any bit in memory
• Changing the present value of any word or any set value in memory
• Make sure that all the mounting screws, terminal screws, and cable con-
nector screws are tightened to the torque specified in the relevant manu-
als.
• Make sure that communications connector screws are securely tightened
to a torque of 0.5 to 0.6 N·m.
• Use crimp terminals for wiring. Do not connect bare stranded wires
directly to terminals.
• Double-check all wiring and switch settings before turning ON the power
supply.
• Make sure that metal filings do not get inside of the Unit during wiring and
installation.
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