Safely-Limited Speed (Sls); Safely-Limited Speed With Encoder - Siemens SINAMICS S120 Function Manual

5.6

Safely-Limited Speed (SLS)

The Safely Limited Speed (SLS) function is used to protect a drive against unintentionally
high speeds. This is achieved by monitoring the current drive speed up to a speed limit.
Safely Limited Speed prevents a parameterized speed limit from being exceeded. Limits
must be specified based on results of the risk analysis. Up to 4 different SLS speed limits
can be parameterized via parameter p9531[0..3].
5.6.1

Safely-Limited Speed with encoder

Features
● A selected speed limit is activated once SLS has been selected and after the delay time
● However, if the ACTUAL speed is higher than the new speed limit value after the delay
● The stop responses are parameterized using p9363/p9563.
● The delay time is not active when switching over to a higher speed limit value.
● 4 parameterizable speed limit values p9331[0...3] and p9531[0...3]
A speed setpoint limit can be set as percentage in p9533. This value is used to calculate a
speed setpoint limit r9733, depending on the selected speed limit p9531[x].
Contrary to parameterizing the safely-limited values, these parameters specify the limit value
on the motor side and not on the load side.
● r9733[0] = p9531[x] * p9533; x = selected SLS stage
● r9733[1] = - p9531[x] * p9533; x = selected SLS stage
Safety Integrated
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
(p9351/p9551) has elapsed. When switching over to a lower speed limit value, the speed
must be braked to below the new maximum limit value within this delay time.
time has expired, an appropriate signal is generated with the parameterized stop
response.
v
v2
v 1
Figure 5-5 Delay time SLS speed limit value
Delay time
Safety Integrated Extended Functions
5.6 Safely-Limited Speed (SLS)
t
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