Rockwell Automation 2094-EN02D-M01-S0 Kinetix 6200 and Kinetix 6500 Safe Torque-off Safety Reference Manual - Manual (Page 10)

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Rockwell Automation Publication 2094-RM002B-EN-P - May 2012
Chapter 1
Safety Concept
Important Safety Considerations
You are responsible for the following:
• The set-up, safety rating, and validation of any sensors or actuators
connected to the system
• Completing a system-level risk assessment and reassessing the system any
time a change is made
• Certification of the system to the desired safety performance level
• Project management and proof testing
• Access control to the system, including password handling
Safety Category 4 Performance Definition
The safety-related parts have to be designed with the following considerations to
achieve Safety Category 4 according to ISO 13849-1:2006:
• The safety-related parts of machine control systems and/or their protective
equipment, as well as their components, must be designed, constructed,
selected, assembled, and combined in accordance with relevant standards
so that they can withstand expected conditions.
• Basic safety principles must be applied.
• A single fault in any of its parts does not lead to a loss of safety function.
• A single fault is detected at or before the next demand of the safety
function, or, if this detection is not possible, then an accumulation of faults
must not lead to a loss of the safety function.
• The average diagnostic coverage of the safety-related parts of the control
system must be high, including the accumulation of faults.
• The mean time to dangerous failure of each of the redundant channels
must be high.
• Measures against common cause failure must be applied.
Stop Category 0 Definition
Stop Category 0 is achieved with immediate removal of power to the actuator,
resulting in an uncontrolled coast to stop. Safe Torque Off accomplishes a Stop
Category 0 stop.
IMPORTANT When applying functional safety, restrict access to qualified, authorized
personnel who are trained and experienced.
ATTENTION: When designing your system, consider how personnel will exit
the machine if the door locks while they are in the machine. Additional
safeguarding devices may be required for your specific application.