Omron RX2 Series - Overview of STO Function

Appendices B STO Function
B - 2
High-function General-purpose Inverter RX2 Series User’s Manual
B-1 Overview of STO Function
3G3RX2-series is an inverter built- in STO (Safe torque off) function defined in IEC 61800-5-2.
STO Function is used to shut off the motor current with input signals from a safety controller and to stop
the motor.
This function is equivalent to stop category 0 defined in EN/IEC60204-1.
Precautions for Correct Use
Design
• The 3G3RX2-series does not feature a function to retain STO status. When STO input is
reset, the inverter goes into a state of operation enabled and starts the operation when oper-
ation command is input.
• Design a system to disallow hazardous status when STO input is reset with consideration
mentioned earlier.
• In default data set before shipment, STO function is disabled by short-circuit wires.
Installment
• Qualified engineers that have enough knowledge about function/safety shall install the
inverter.
Wiring
• The 3G3RX2-series does not feature a function to carry out diagnosis of STO input signals.
Be sure to design a system that can provide 2 inputs normally. As necessary, carry out error
diagnosis for input path with EDM signal output.
• STO input signals via two channels outside the inverter shall be separated and protected
appropriately. No interruption shall be made on each signal.
• The cable length for signals connected to ST1/ST2 or EDM terminal shall be each 20m or
less.
Test Run
• Be sure to conduct a test run to verify safety system and check the validity. The safety sys-
tem without this check shall not be regarded as “Safe”.
Maintenance
• STO function does not cut off the power supplies for the inverter main circuit and its periph-
eral circuit. When you make maintenance, be sure to separate a safety system away from
the main power supply or devices like permanent magnet motors or capacitors to which volt-
age is likely supplied.
• Be sure to carry out the followings before the maintenance:
• Wait for ten minutes or more
*1
or fifteen minutes or more
*2
after cutting off power supply.
• Check that voltage between PN terminals is 45V or less after a charge LED goes out.
• Be sure to conduct periodic function test every year.
Others
• Never modify the inverter. The modified inverter is out of conformity with criteria and product
guarantee.
*1 In the case of 3G3RX2-A2004 to -A2220 / -A4007 to -A4220
*2 In the case of 3G3RX2-A2300 to -A2550/ -A4300 to -A4550/ -B4750/ -B4900/ -B411K/
-B413K