Omron CJ1M-CPU21, Operation Manual

Page: 23 / 267

xxiv
Operating Environment Precautions 4
!Caution A CJ1M CPU Unit automatically back up the user program and parameter
data to flash memory when these are written to the CPU Unit. I/O memory
(including the DM, EM, and HR Areas), however, is not written to flash mem-
ory. The DM, EM, and HR Areas can be held during power interruptions with a
battery. If there is a battery error, the contents of these areas may not be
accurate after a power interruption. If the contents of the DM, EM, and HR
Areas are used to control external outputs, prevent inappropriate outputs from
being made whenever the Battery Error Flag (A40204) is ON. Areas such as
the DM, EM, and HR Areas, the contents of which can be held during power
interrupts, is backed up by a battery. If a battery error occurs, the contents of
the areas that are set to be held may not be accurate even though a memory
error will not occur to stop operation. If necessary for the safety of the system,
take appropriate measures in the ladder program whenever the Battery Error
Flag (A40204) turns ON, such as resetting the data in these areas.
!Caution Tighten the screws on the terminal block of the AC Power Supply Unit to the
torque specified in the operation manual. The loose screws may result in
burning or malfunction.
4 Operating Environment Precautions
!Caution
Do not operate the control system in the following locations:
• Locations subject to direct sunlight.
• Locations subject to temperatures or humidity outside the range specified
in the specifications.
• Locations subject to condensation as the result of severe changes in tem-
perature.
• Locations subject to corrosive or flammable gases.
• Locations subject to dust (especially iron dust) or salts.
• Locations subject to exposure to water, oil, or chemicals.
• Locations subject to direct shock or vibration.
!Caution Take appropriate and sufficient countermeasures when installing systems in
the following locations:
• Locations subject to static electricity or other forms of noise.
• Locations subject to strong electromagnetic fields.
• Locations subject to possible exposure to radioactivity.
• Locations close to power supplies or power lines.
!Caution
The operating environment of the PLC System can have a large effect on the
longevity and reliability of the system. Improper operating environments can
lead to malfunction, failure, and other unforeseeable problems with the PLC
System. Be sure that the operating environment is within the specified condi-
tions at installation and remains within the specified conditions during the life
of the system.