Omron SYSMAC CJ Series, Operation Manual

Page: 8 / 371

Operating environment precautions 4
viii
!WARNING Provide safety measures in external circuits (i.e., not in the Programmable Controller)
to ensure safety in the system if an abnormality occurs due to malfunction of the PLC,
malfunction of the CJ1W-MCH72, or external factors affecting the operation of the PLC
or CJ1W-MCH72. Not providing sufficient safety measures 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 turn OFF all outputs when its self-diagnosis function detects any error
or when a severe failure alarm (FALS) instruction is executed. As a countermeasure
for such errors, external safety measures must be provided to ensure safety in the
system.
• The PLC or CJ1W-MCH72 outputs may remain ON or OFF due to deposits on 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 V DC 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.
•
External safety measures must also be taken to ensure safety in the event of
unexpected operation when connecting or disconnecting the connectors of the
CJ1W-MCH72.
!Caution
User programs written to the CJ1W-MCH72 will not be automatically backed up in the
CJ1W-MCH72 flash memory (flash memory function).
!Caution
Tighten the screws on the terminal block of the Power Supply Unit to the torque
specified in this manual. Loose screws may result in burning or malfunction.
!Caution
When positioning to a position determined using the teaching function, set the position
designation setting in the positioning sequence to absolute positioning. If it is set to
relative positioning, positioning will be performed to a position other than the one
obtained with the teaching function.
!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
Confirm the safety of the destination node before transferring a program to the node or
changing the contents of I/O memory. Doing either of these without confirming safety
may result in injury.
!Caution
Do not save data into the flash memory during memory operation or while the motor is
running. Otherwise, unexpected operation may be caused.
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 temperature.
• 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:
• Locations subject to static electricity or other forms of noise.
• Locations subject to strong electromagnetic fields.