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Appendix A
Using the Safe Torque-off Feature with the Kinetix 6000M System
Description of Operation
104
Category 3 Requirements According to EN ISO 13849-1
Safety-related parts are designed with these attributes:
• A single fault in any of these parts does not lead to the loss of the safety
function
• A single fault is detected whenever reasonably practicable
• Accumulation of undetected faults can lead to the loss of the safety
function, which results in failure to remove motion producing power from
the motor.
Stop Category Definition
Stop category 0 as defined in EN 60204 or Safe Torque Off as defined by EN
61800-5-2 is achieved with immediate removal of motion producing power to
the actuator.
In the event of a malfunction, the most likely stop category is category 0. When
IMPORTANT
designing the machine application, timing and distance should be considered
for a coast to stop. For more information regarding stop categories, refer to
EN 60204-1.
Performance Level (PL) and Safety Integrity Level (SIL)
For safety-related control systems, Performance Level (PL), according to EN ISO
13849-1, and SIL levels, according to EN 61508 and EN 62061, include a rating
of the systems ability to perform its safety functions. All of the safety-related
components of the control system must be included in both a risk assessment and
the determination of the achieved levels.
Refer to the EN ISO 13849-1, EN 61508, and EN 62061 standards for complete
information on requirements for PL and SIL determination.
The safe torque-off feature provides a method, with sufficiently low probability
of failure, to force the power-transistor control signals to a disabled state. When
disabled, or any time power is removed from the safety enable inputs, all of the
IDM output-power transistors are released from the On-state. This effectively
removes power generated by each IDM unit connected to a single IPIM module
and utilizing connections to an external safety device (E-stop, light curtains, etc.).
This results in a condition where the IDM unit is coasting (stop category 0).
Disabling the power transistor output does not provide mechanical isolation of
the electrical output, which may be required for some applications.
Under normal operation, the safe torque-off inputs are energized. If either of the
safety enable inputs are de-energized, then all of the output power transistors will
turn off. The safe torque-off response time is less then 12 ms.
Rockwell Automation Publication 2094-UM003A-EN-P - May 2012
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