Omron CVM1 Series, Operation Manual

Page: 14 / 110

xv
Application Precautions 5
!Caution Failure to abide by the following precautions could lead to faulty operation of
the PLC or the system, or could damage the PLC or PLC Units. Always heed
these precautions.
• Do not mount more than the maximum number of PC Link Units specified
in this manual to one PLC. The PLC may malfunction.
• Make sure that only the PC Link Unit model combinations specified in this
manual are used. Correct communications may not be possible for some
PC Link Unit model combinations.
• Check all switch settings to be sure they agree with the information pro-
vided in this manual. Incorrect switch settings may cause malfunctions.
• Attach all protective covers in the locations specified in this manual.
• Make sure that all the Backplane mounting screws, terminal block screws,
and cable connector screws are tightened to the torque specified in the
relevant manuals. Incorrect tightening torque may result in malfunction.
• 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 objects on top of the communications cables.
• Always lay communications cable inside ducts.
• Double-check all wiring and switch settings before turning ON the power
supply.
• Do not allow wire clipping or scraps to enter the Unit. Be particularly care-
ful during wiring work.
• Make sure that the terminal blocks, Memory Units, expansion cables, and
other items with locking devices are properly locked into place. Improper
locking may result in malfunction.
• Check the user program for proper execution before actually running it on
the Unit. Not checking the program may result in unexpected operation.
• 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.
• After replacing a CPU Unit, resume operation only after transferring to the
new CPU Unit the contents of the DM Area, HR Area, and other data
required for resuming operation. Not doing so may result in an unex-
pected operation.
• Before touching a Unit, be sure to first touch a grounded metallic object in
order to discharge any static build-up. Not doing so may result in malfunc-
tion or damage.