Safe Stop 1 (SS1)

The SS1 function causes a motor to stop rapidly and safely and switches the motor to torque-free mode after the standstill, i.e. STO is activated.


The Safe Stop 1 function can safely stop the drive in accordance with EN 60204-1, Stop Category 1. When the SS1 functionis selected, the drive brakes along a quick stop ramp autonomously and automatically activates the Safe Torque Off and Safe Brake Control functions (if enabled) when the parameterized safety delay timer expires.


The SS1 function is used when in the event of a safety-relevant incident the drive must stop as quickly as possible with a subsequent transition into the STO state.
It is thus used to bring large centrifugal masses to a stop as quickly as possible for the safety of operating personnel, or to brake motors at high speeds as quickly as possible.
Typical application examples include:

  • Saws, grinding machine spindles, centrifuges, stacker cranes

Customer benefits

The targeted stopping of a drive by means of SS1 reduces the risk of danger, increases the productivity of a machine, and allows safety clearances in a machine to be reduced. The reason is the active stopping of the drive compared to the use of the STO function alone.