Omron CS1W-MCH71 Operation Manual page 43

Application Precautions
4 Application Precautions
Observe the following precautions when using the MC Unit or the PLC.
• Install external breakers and take other safety measures against short-circuiting in external wiring.
Insufficient safety measures against short-circuiting may result in burning.
• Always turn off after power supply to the Unit before attempting any of the following. Not turning OFF
the power supply may result in malfunction or electric shock.
• Mounting or dismounting the MC Unit or any other unit.
• Assembling the Units.
• Setting Rotary switches.
• Connecting Cables or wiring the system.
• Connecting or disconnecting the connectors.
• Confirming 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 operation mode of the PLC (including the setting of the startup operating mode).
• Changing the present value of any word or any set value in memory.
• Force-setting /force-resetting any bit in memory.
• Always connect to a ground of 100 Ω or less when installing the Units. Not connecting to a ground of
100 Ω or less may result in electric shock.
• Before touching the Unit, be sure to first touch a grounded metallic object in order to discharge any
static built-up. Not doing so may result in malfunction or damage.
• Be sure that all the mounting screws, terminal screws, and cable connector screws are tightened to
the torque specified in this manual. Incorrect tightening torque may result in malfunction.
• Tighten the mounting screws at the bottom of the Unit to a torque of 0.4 N·m.
Incorrect tightening torque may result in malfunction.
• Perform wiring according to specified procedures.
• Leave the label attached to the Unit when wiring. Removing the label may result in malfunction if for-
eign matter enters the Unit.
• Remove the label after the completion of wiring to ensure proper heat dissipation. Leaving the label
attached may result in malfunction.
• Check the pin numbers before wiring the connectors.
• Use crimp terminals for wiring. Do not connect bare stranded wires directly to terminals. Connection
of bare stranded wires may result in burning.
• Be sure that the connectors, terminal blocks, I/O cables, cables between drivers, and other items with
locking devices are properly locked into place. Improper locking may result in malfunction.
• Always use the power supply voltage specified in this manual. An incorrect voltage may result in mal-
function or burning.
• 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 in correct power
supply may result in malfunction.
• Do not apply voltages to the Input Units in excess of the rated input voltage. Excess voltage may
result in burning.
• Do not apply voltages or connect loads to the Output Units in excess of the maximum switching
capacity. Excess voltages or loads may result in burning.
• Check carefully all wiring and switch setting before turning ON the power supply. Incorrect wiring may
result in burning.
• Separate the line ground terminal (LG) from the functional ground terminal (GR) on the Power Supply
Unit before performing withstand voltage tests or insulation resistance tests. Not doing so may result
in burning.
• Do not place objects on the top of the cables or other wiring lines.
Doing either of these may break the cables.
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