Machine Safety
Safety Stop Category Selection (IEC 60204-1)
Determine the appropriate stop category and required safety stop time based on machine characteristics and risk level.
Units:
Stop Category 0 is the safest — power is immediately removed. Category 1 is a controlled stop with delayed power removal. Category 2 maintains power for CNC / servo systems where stopping position matters. Never use Category 2 as a safety stop unless specifically designed for it.
Category 0: Immediate removal of power (coast to stop)
Category 1: Controlled stop → power removed when stopped
Category 2: Controlled stop → power maintained
Input
Machine type / drive type iThe type of drive directly affects which stop category is feasible.
Required PLr iRequired Performance Level determined from risk assessment.
Measured / estimated stop time iTime for the machine axis to reach standstill after stop command, in milliseconds. Measure on actual machine.
ms
Result
Recommended stop category
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Required standstill monitoring
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Typical safety device
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Implementation notes
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