Omron NX-PA Series User Manual page 21

Operation
• Confirm that no adverse effect will occur in the system before you attempt any of the following.
a) Changing the operating mode of the CPU Unit (including changing the setting of the Startup
Mode)
b) Changing the user program or settings
c) Changing set values or present values
d) Forced refreshing
• After you change any slave or Unit settings, carefully check the safety of the controlled system before
you restart the Unit.
• If two different function modules are used together, such as when you use EtherNet/IP and EtherCAT
slaves, take suitable measures in the user program and external controls to ensure that safety is
maintained in the controlled system if one of the function modules stops. The relevant outputs will
behave according to the slave or Unit specifications if a partial fault level error occurs in one of the
function modules.
• Always confirm safety at the connected equipment before you reset Controller errors with an event
level of partial fault or higher for the EtherCAT Master Function Module.
When the error is reset, all slaves that were in any state other than Operational state due to a Con-
troller error with an event level of partial fault or higher (in which outputs are disabled) will go to Oper-
ational state and the outputs will be enabled.
Before you reset all errors or restart a slave, confirm that no Controller errors with an event level of
partial fault have occurred for the EtherCAT Master Function Module.
• Always confirm safety at the connected equipment before you perform the following operations when
the device output hold configuration is set to enable. The equipment may operate unexpectedly
because the last status for outputs is retained.
a) Changing the operating mode of the CPU Unit
b) When downloaded
Battery Backup
• The user program and initial values for the variables are stored in non-volatile memory in the CPU
Unit. The present values of variables with the Retain attribute and the values of the Holding, DM, and
EM Areas in the memory used for CJ-series Units are backed up by a Battery.
If the Battery is not connected or the Battery is exhausted, the CPU Unit detects a Battery-backup
Memory Check Error.
If that error is detected, variables with a Retain attribute are set to their initial values and the Holding,
DM, and EM Areas in memory used for CJ-series Units are cleared to all zeros.
Perform thorough verifications and provide sufficient measures to ensure that the devices perform
safe operation for the initial values of the variables with Retain attributes and the resulting operation.
• The absolute encoder home offsets are backed up by a Battery. If the CPU Unit detects a low battery
voltage or the absence of a mounted battery when the power supply to the Controller is turned ON,
the absolute encoder home offsets are cleared to zeros and an Encoder Home Offset Read Error
occurs. Reset the error and perform homing to define home. If you do not define home, unintended
operation of the controlled system may occur.
NX-series CPU Unit Hardware User's Manual (W535)
Precautions for Safe Use
19