STO safety concept

The device is supposed to be able to perform the safety subfunction "Safe Torque Off" according to EN 61800‑5‑2:

  • The STO function is activated via the MOVISAFE® CS..A safety option.
  • An internal structure with diagnostics prevents the generation of pulse trains at the power output stage (IGBT).
  • If the internal diagnostics detects a fault, the PWM signals are permanently switched off.
  • If the internal diagnostics of the STO circuit detects a fault, the PWM signals are locked, i.e. the STO is activated. Latching requires a reset by switching off and on the DC 24 V supply voltage to the device or an acknowledgment of the safety option via safe digital input F-DI or via PROFIsafe.