Omron NX-SL3300 User Manual page 29

• Make sure that the voltages and currents that are input to the Units and slaves are within the speci-
fied ranges. Inputting voltages or currents that are outside of the specified ranges may damage the
Units or slaves or cause fire.
Actual Operation
• 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
• Do not disconnect the cable or turn OFF the power supply to the Controller or a Slave Terminal
when downloading data or the user program from the Support Software.
• Always turn OFF the external power supply to the Units before attempting any of the following.
a) Mounting or removing an NX Unit.
b) Assembling Units
c) Setting DIP switches or rotary switches
d) Connecting or wiring cables
e) Attaching or removing terminal blocks or connectors
The Power Supply Unit may continue to supply power to the Controller for a few seconds after the
power supply turns OFF. The UNIT PWR and I/O PWR indicators are lit during this time. Confirm
that the UNIT PWR and the I/O PWR indicators are not lit before you perform any of the above ac-
tions.
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 CPU Unit or Communications Coupler Unit for precautions for the
safe use of communications with the connected CPU Unit or 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.
NX-series Safety Control Unit User's Manual (Z930)
Precautions for Safe Use
27