SS2-t – Safe Stop 2 with time control
When the SS2-t function is active, the drive inverter brings the motor to a standstill electrically. At standstill, the drive inverter delivers the power to keep the motor in position. The position must be safely monitored after a specified, safety-related time has elapsed (SOS function according to EN 61800‑5‑2). Any movement at standstill triggers the safety sub-function STO. STO means that standstill has to be ensured by a mechanical brake.
This safety sub-function corresponds to a controlled stop of the drive according to EN 60204‑1, stop category 2.
| = | Safety sub-function monitored |
| = | Safety sub-function STO active |
v | = | Speed |
t | = | Time |
t1 | = | Point in time when SS2-t is activated and motor deceleration is triggered. |
t2 | = | Point in time when SOS is triggered. |
Δt | = | Safety-relevant period of time |
INFORMATION
- The SS2-t function does not monitor the stopping of the drive.
- The safety-relevant period of time Δt allows the drive to come to a stop. In the event of a fault, the drive does not come to a stop and only becomes de-energized at the time t2 (STO).
