Siemens SIMATIC S7-300 Product Information page 201

SINAMICS Drive Systems
Safely Limited Speed (SLS)
When SLS is selected, the drive continues to follow the setpoint interface and activates the
velocity monitoring after the delay time (p9351/p9551) configured in the drive.
Response in the user program
When SLS is selected (displayed in StatuswordSafety.SLS_Deselected=FALSE
(DBx 140.4)), the speed is reduced within the configured delay time to the maximum speed
defined by the TO DB variable, safeSpeedLimit.
When SLS is deselected, the drive deactivates the velocity monitoring. The drive can
traverse again without restriction provided no other safety function is active.
● For selected SLS, the drive is in the monitored standstill (SOS or SS2)
● Axis performs motion
● Modification of velocity limitation
Connection of the SINAMICS S120 to the Technology CPU
Product Information, 09/2011, A5E00480378-04
The drive is in the monitored standstill (by a previous selection of SS2 or SOS).
A motion can then only be executed if SS2 and SOS are not active
(StatuswordSafety.SS2_Active=FALSE (DBx 140.2) and
StatuswordSafety.SOS_Selected=FALSE (DBx 140.3)).
Response in the user program:
When SS2 and SOS are deselected, a motion is permitted immediately with the
displayed maximum velocity safeSpeedLimit.
When SLS is selected, the axis traverses with a higher velocity than preselected
with SLS.
Response in the user program:
When SLS is selected (without stop function also active at the same time), the axis must
be reduced to the maximum velocity displayed as safeSpeedLimit within the configured
delay time.
The velocity limit value monitored in the drive can be changed dynamically. A reduction of
the limit value is critical because the deceleration must be performed in the user program
to prevent violation of the new limit value.
Response in the user program:
If SLS is active (and all stop functions are inactive), the safeSpeedLimit system variable
will be monitored for change:
– new safeSpeedLimit > old safeSpeedLimit: Higher velocity permitted immediately
– new safeSpeedLimit > old safeSpeedLimit: Deceleration and limitation to the new limit
value within the configured delay time
Safety Integrated Functions in
6.5 Behavior and reactions in the user program
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