Safety-rated Stop Subfunction

Safety-rated stop subfunction is used to stop the robot when Safety-Rated Monitoring Function detects limit violation , when a stop signal is received from the dedicated input terminal of Safety-Rated Stop Function, or when a stop signal is received from the configurable input terminal of Safety-rated I/O set as one of the Safety-rated Stop Subfuctions.

Note

PFHd (Probability of a dangerous Failure per Hour): The probability of dangerous failures of safety-related system/subsystem per hour
PL (Performance Level): The performance level of safety-related components (SRP/CS) of control system according to ISO 13849-1
SIL (Safety integrity level): The safety integrity level of safety-related electronic control systems (SRECS or SCS) according to IEC 62061
Stop Category: The category of stop functions defined by IEC 60204-1

Safety Function

Description

PFHd

PL, SIL

1

STO

(Safe Torque Off)

&

SBC

(Safe Brake Control)

It is the safety stop function corresponding to Stop Category 0, and it immediately cuts motor power to all joint modules.

WIth motor power down, the axis will continue to rotate due to inertia, so the brakes must be operated simultaneously to stop with frictional force of the brake.

As the motor power is cut off, the robot can be operated after releasing the stop function and setting the Servo On.
For more information about servo on methods, refer to Overview of Servo On.

The robot brake is used for maintaining the current pose when driving force is lost (i.e., power off, etc.) not for deceleration. Frequently using STO can result in brake wear or decelerator durability loss, so it is recommended to use SS1 unless necessary.

2.87E-8

/h

PL e Cat. 4

SIL 3

2

SS1

(Safe Stop 1)

This is the safety stop equivalent of Stop Category 1, which decelerates all joints to the maximum possible to stop, then cuts the power to the motor and engages the brake to keep it stationary.

If the predefined deceleration does not occur normally during stopping, it is switched to STO stop.
Power is cut off after deceleration, and like STO, the robot can be operated after releasing the stop function and setting the Servo On.
For more information about servo on methods, refer to Overview of Servo On.

4.63E-7

/h

PL d Cat. 3

SIL 2

3

SS2

(Safe Stop 2)

This is the safety stop equivalent of Stop Category 2, which decelerates all joints to the maximum possible to stop, then switches it to the stop status monitoring function.

If the predefined deceleration does not occur normally during stopping, it is switched to STO stop.
All joints are stopped with maximum deceleration by a Stop Mode corresponding to Stop Category 2, and SOS (Safe Operating Stop) is engaged.

4.63E-7

/h

PL d Cat. 3

SIL 2

4

Reflex Stop

(RS1)

It is the safety stop function corresponding to Stop Category 2, and it utilizes Floating Reaction ( a function to comply with the external force for a moment after the collision is detected) to respond to external force, and Safe Operating Stop (SOS) is engaged.

If excessive location, change in direction or speed is detected during Floating Reaction, or if deceleration is not done appropriately during stopping, STO stop is engaged.

4.65E-7

/h

PL d Cat. 3

SIL 2