Safe Stop 1 (SS1)

The SS1 function causes a motor to stop rapidly and safely and switches the motor to exert no torque at all after coming to a 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 function is 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 configured safety delay timer expires.


The SS1 function is used when, in the event of a safety related incident, the drive must stop as quickly as possible and then enter the STO state (e.g. in the case of an EMERGENCY STOP). 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 applications include, for example:

  • Saws, grinding machine, centrifuges, stacker cranes, winders

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 as compared with the use of the STO function only. Complex, wear-prone mechanical brakes for stopping the motor are usually not required.