Operating Environment Precautions - Omron SmartSlice GRT1-OD4G-1 Operation Manual

Operating Environment Precautions

!WARNING
!WARNING
4 Operating Environment Precautions
Provide safety measures in external circuits (i.e., not in the Programmable
Controller), including the following items, to ensure safety in the system if an
abnormality occurs due to malfunction of the PLC or another external factor
affecting the PLC operation. Not doing so may result in serious accidents.
• Emergency stop circuits, interlock circuits, limit circuits, and similar safety
measures must be provided in external control circuits.
• The PLC will stop operation when its self-diagnosis function detects any
error or when a severe failure alarm (FALS) instruction is executed. Unex-
pected operation, however, may still occur for errors in the I/O control
section, errors in I/O memory, and other errors that cannot be detected by
the self-diagnosis function. As a countermeasure for all such errors,
external safety measures must be provided to ensure safety in the sys-
tem.
• The PLC outputs may remain ON or OFF due to deposits on or burning of
the output relays, or destruction of the output transistors. As a counter-
measure for such problems, external safety measures must be provided
to ensure safety in the system.
• When the 24-VDC output (service power supply to the PLC) is overloaded
or short-circuited, the voltage may drop and result in the outputs being
turned OFF. As a countermeasure for such problems, external safety
measures must be provided to ensure safety in the system.
• Slice I/O Terminals will continue operating even if one or more I/O Units is
removed from or falls out of the Slice I/O Terminal, i.e., the other I/O Units
will continue control operations, including outputs. As a countermeasure
for such a possibility, external safety measures must be provided to
ensure safety in the system.
The CPU Unit refreshes I/O even when the program is stopped (i.e., even in
PROGRAM mode). Confirm safety thoroughly in advance before changing the
status of any part of memory allocated to Output Units, Special I/O Units, or
CPU Bus Units. Any changes to the data allocated to any Unit may result in
unexpected operation of the loads connected to the Unit. Any of the following
operations may result in changes to memory status.
• Transferring I/O memory data to the CPU Unit from a Programming
Device
• Changing present values in memory from a Programming Device
• Force-setting/-resetting bits from a Programming Device
• Transferring I/O memory files from a Memory Card or EM file memory to
the CPU Unit
• Transferring I/O memory from a host computer or from another PLC on a
network
Install the system properly according to the directions in this manual.
Do not operate the control system in the following places.
• Locations subject to direct sunlight.
• Locations subject to temperatures or humidity outside the range specified
in the specifications.
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