Functional Safety
8.1.5
Restart Lock Procedure
The following diagram shows the restart lock procedure by means of a time axis, includ-
ing the required steps that must be performed in order to be able to restart the device
after an activated restart lock.
Switch on
SAFE A
SAFE B
Device status
error
Device status
restart lock
Error reset
t
t
t
t
t
t
Speed
N
(must be confirmed)
(error confirmation)
(warning)
A
B
(coast to
standstill)
STO
Feedback
t
Fig. 77: Behavior STO / restart lock - timing and required actions
Use case A
If an STO contact is interrupted during “Switch off”, the device status “Switch on dis-
abled” is triggered. As soon as the STO contact is closed again, the drive can restart
with the next “Switch on”.
Use case B
If an STO contact is interrupted during “Switch on”, the device status “Error” is trig-
gered. The error must be confirmed via an error reset to continue operation.
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Drive System SD4S - Hardware Description
