Safety concept

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

• The device is characterized by the optional connection of an external safety controller/safety relay. This external safety controller/safety relay disconnects the safety-related STO input via a dual-channel 24 V switching signal (e.g. sourcing/sinking) when a connected command device (e.g. emergency stop button with latching function) is activated. This activates the STO function of the device.
• 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 locked.
• Instead of galvanic isolation of the drive from the supply voltage by means of contactors or switches, the disconnection of the STO input described here safely prevents the activation of the power semiconductors in the output stage. The rotary-field generation for the respective motor is deactivated even though the supply voltage is still present.
• When the STO safety subfunction is activated, the PWM signals generated by the device are interrupted and not transmitted to the IGBTs.
• If the STO function detects a discrepancy between both channels, the PWM signals are inhibited. The interlocking can be revoked by a 24 V reset, or by a device reset if F_STO_P is not controlled with 24 V.
• The STO safety subfunction can be activated externally e.g. via an external safety device via the STO input.