Omron NX-SID Series User Manual page 23

Actual Operation
• Before you start operation, always register the NX Units that are connected to the Communications
Coupler Unit in the host communications master as the Unit configuration information.
• The relevant Units will maintain the safe states for I/O data with safety connections after an error is
detected in safety process data communications. However, when the cause of the error is removed,
safety process data communications will recover automatically. If you need to prevent equipment
from restarting when safety process data communications recover automatically, implement suitable
restart conditions in the user program.
Turning OFF the Power Supply
• Always turn OFF the external power supply to the Units before attempting any of the following.
Mounting or removing an NX Unit, Communications Coupler Unit, or CPU Unit
Assembling Units
Setting DIP switches or rotary switches
Connecting or wiring cables
Attaching or removing terminal blocks or connectors
Units that supply power continue to supply power to the Units for up to several seconds after the
power supply is turned OFF. The PWR indicator remains lit as long as power is supplied. Confirm that
the PWR indicator is not lit before you perform any of the above.
General Communications
• Do not exceed the ranges that are given in the specifications for the communications distance and
number of connected Units.
• Refer to the user's manual for the Communications Coupler Unit for precautions for the safe use of
communications with the connected Communications Coupler Unit.
Standards
• The customer is responsible for attaining conformance of the entire system to standards.
Maintenance
• Test the functionality every six months to detect welded contactor contacts.
To detect electrical and mechanical failures, use a combination of redundant semiconductor output
contacts and redundant mechanical output devices.
Unit Replacement
• After you replace the Safety Control Unit, set the program and all configuration settings that are nec-
essary to resume operation. Make sure that the safety functions operate normally before you start
actual operation.
• When you replace a Unit, start operation only after you transfer the settings and variables that are
required for operation to the new Unit.
Disposal
• Dispose of the product according to local ordinances as they apply.
NX-series Safety Control Unit User's Manual (Z930)
Precautions for Safe Use
21