Safety Instructions On Function „Safe Torque Off" (Sto) - BONFIGLIOLI Agile Series Application Manual Functional Safety

3 Safety Instructions on Function „Safe Torque Off" (STO)
The function „Safe Torque Off" (STO) is a functional safety provision, i.e. it protects
persons from damage, provided that projecting, installation and operation are per-
formed properly. This function does not disconnect the machine from power supply.
The safety function "Safe torque off" (STO) can be used to realize an "Emergency
Stop" according to EN 60204 while the power supply is still active on the frequency
inverter
A provision must be provided for disconnecting the machine from power supply for
maintenance work.
With a suitable external safety control device the function „Safe Stop 1 (SS1 c)" ac-
cording to EN 61800-5-2 can be realized together with the AGL.
Danger!
AGL-STOV0-01SV0-05
06/12
Improper installation of the safety technique can cause an uncontrolled
starting of the drive. This may cause death, serious injuries and signifi-
cant material damage.
Safety functions may only be installed and commissioned by qualified
staff.
The STO function is not suitable for emergency switch off as per
EN 60204. An emergency switch off can be realized by installing a
mains contactor.
An emergency stop according to EN 60204 must be functioning in all
operation modes of the frequency inverter. Resetting of an emergency
stop must not result in uncontrolled starting of the drive.
The drive is started again when the function STO is no longer triggered.
In order to comply with standards EN 60204 and EN 1037, it must be
ensured by taking external measures that the drive only starts after e
manual confirmation.
Without a mechanical brake, the drive might not stop immediately but
coast to a standstill. If this may result in personal or material damage,
additional safety measures must be taken.
If persons may be endangered after disconnection of the motor control
by STO, access to the hazard areas must be prevented until the drive
has stopped.
Check the safety function at regular intervals according to the results of
your risk assessment. BONFIGLIOLI VECTRON recommends that the
check is performed after one year, at the latest.
The STO function is one fault fail-safe. No single fault or component
failure can cause a disabled drive to produce motor shaft torque. Only
in extremely unlike combinations of component faults the motor shaft
could move jerky with sudden acceleration (maximum 180°/number of
pole pairs, for example jerky movement of 90° for 4-pole motor,
180°/2) and produce torque. It must be checked if this behavior can
cause a dangerous machine movement.
If the STO function is used, the special safety, installation and instruc-
tions on use instructions shall be complied with.
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