Safe Torque Off Function - Omron R88D-KN series User Manual

8 Safety Function
8-1

Safe Torque OFF Function

The safe torque OFF function (hereinafter referred to as STO according to IEC 61800-5-2) is used to
cut off the motor current and stop the motor with the input signals from a safety device, such as a safety
controller or safety sensor.
When the STO function is operating, the
(READY) to go into the safety status.
To connect a Servo Drive to safety devices such as a safety controller or a safety sensor, use the safety
connector (CN8).
The PFH value is 2.30 10
Precautions for Safe Use
• When using the STO function, be sure to execute a risk assessment of the equipment to
confirm that the system safety requirements are met.
• There are the following risks even when the STO function is operating. Be sure to take safety
into account as part of the risk assessment.
• The motor runs if an external force is present. If holding is required, implement appropriate
measures, such as providing external brakes.
• Even if there is no external force, when the Fault reaction option code (605E hex) is set to
free-run with the dynamic brake disabled, the motor uses free-run stopping and the stop
distance is long.
• In case of internal failure of components, the motor may operate in the range of up to 180
degrees of electrical angle.
• The power supply to the motor is cut off by the STO function, but the power supply to the
Servo Drive
power supply to the
• Do not use the EDM output for any purpose other than the failure monitoring function. The
EDM output signal is not a safety output.
• The dynamic brake and external brake release signal outputs are not safety-related parts.
Make sure to design the equipment not to be dangerous even if the external brake release fails
during the STO status.
• When using the STO function, connect equipment that meets the safety standards.
Precautions for Correct Use Precautions for Correct Use
According to EN61800-5-2, the safety function is referred to as the "Safe torque off" function
using the word "torque" instead of force. Read it as "force" when using this function.
8-2
Servo Drive
8
.
will not be cut off nor electrically isolated. For
through another means.
Servo Drive
G5 Series AC Servo Drives With Built-in EtherCAT Communications, Linear Motor Type
turns OFF the servo ready completed output
Servo Drive
maintenance, cut off the