Safe torque off (STO)
Properties
- Safety function according to DIN EN 61800-5-2:2008-04
- Uncontrolled stop according to EN 60204-1, stop category 0
- The drive is immediately (≤ 10 ms) switched torque-free (Siehe 'Propagation delay times'.)
- Protection against unexpected start of the motor
Description
The safety function can be started by a safe input or by the corresponding bit in the control data.
The acknowledgement can be fed back by safe output or by status data.
The STO safety function is started by an 1-0 edge and cannot be interrupted.
In case of active safety function STO, the pulse width modulation (PWM) is blocked on two channels. The PWM controls the transistors of the power output stage of the inverter. In case of two channel blocked PWM, the unexpected start of the motor is prevented safely.
If STO is active, the drive motions are no longer controlled as no further error reaction is possible. 'Safe encoder monitoring (SEM)' and monitoring of the switch-off path furthermore are active.
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If the safety function 'Safe torque off (STO)' is already set during system run-up, the firmware of the controller card will generate the diagnostic message 2320 'EF inactive' due to system characteristics. |
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Danger to life due to unexpected movements! The drive will be torque-free in the status 'Safe torque off (STO)', in case of mains failure or in case of faulty drive controller. External application of force on the drive axis may result in life-threatening movements (e.g. hanging axes can fall down). Steps to prevent:
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Danger of life due to electric shock! Lethal voltages can exist at the motor connection output terminals of the inverter in spite of blocked PWM. Steps to prevent:
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