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4Operating Environment Precautions
xvii
• The PC outputs may remain ON or OFF due to deposition or burning of the
output relays or destruction of the output transistors. As a countermeasure 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 PC) 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.
WARNING When transferring programs to other nodes, or when making changes to I/O
memory, confirm the safety of the destination node before transfer. Not doing so
may result in injury.
Caution Execute online edit only after confirming that no adverse effects will be caused
by extending the cycle time. Otherwise, the input signals may not be readable.
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.
Caution When connecting a personal computer or other peripheral device to the CPM1A,
either ground the 0 V side of the CPM1A or do not ground at all. Depending on
the method of grounding, the 24-V power supply may short-circuit; do not
ground the 24-V side as shown in the following diagram.
Example: Connections where 24-V Power Supply Will Short-circuit
Non-isolated DC
power supply
CPM1A Peripheral device
4 Operating Environment Precautions
Caution 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.
• Locations subject to condensation as the result of severe changes in tempera-
ture.
• 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 shock or vibration.
Caution Take appropriate and sufficient countermeasures when installing systems in the
following locations: