Safe Stop 1 (Ss1) - Lenze i950 Commissioning Manual

19.4

Safe Stop 1 (SS1)

The safety function monitors the parameterised stopping time of the drive (n = 0).
The drive switches to torqueless operation via the parameterised mode in the function SS1
(0x2897:0010x2897:001).
Preconditions
The drive is brought to standstill via the application.
Movements caused by external forces require additional measures. When the stopping time is
defined, the application time of the brake must be taken into consideration.
The restart is possible after the stopping time has completely elapsed. An exception from this
is the special operation.
Functional description
n = 0 means that the motor speed is lower than the motor speed parameterised
in the tolerance window.
The deceleration ramp can be parameterised and monitored for the stop func-
tion SS1.
SS1-t
0x2897:001 = 0 (STO after stopping time)
SS1
n
0x2894/1
b
a
0
0x287B:001
The SS1 safety function switches the inverter to STO if the stopping time
set in 0x2894:001 0x2894:001 (stopping time for SS1 and SS2)
elapsed. The switching operation is triggered irrespective of whether the
motor is at standstill or not!
Curve (a): the motor comes to a standstill within the parameterised
stopping time.
Curve (b): When the motor switches to STO, it is not yet at standstill.
Switching off with STO lets the motor coast to a stop.
Notes on how to set the stopping time
When setting the stopping time
observe the following dependency:
1. If an encoder is available, a speed is calculated from the encoder data.
In 0x2897:0010x2897:001, selection "1": STO at n = 0, a waiting time
•
0x2897:0020x2897:002, deceleration STO after n=0
STO status is activated. This deceleration defines the time between the standstill of the
motor and the activation of STO.
2. If no encoder is available, the function evaluates the speed status n = 0 from the inverter.
In this case, the stopping time
•
0.5 s monitored by the safety system must be parameterised higher than the stopping
time parameterised in the inverter.
0x287B:0010x287B:001, tolerance window
STO
t
has
0x2894:0010x2894:001,stopping time for SS1 and
can be set which defines when the
0x2894:0010x2894:001, stopping time for SS1 and SS2
(n=0).
SS1-t
0x2897:001 = 1 (STO at n = 0)
SS1
n
0x2894/1
b
a
0x2897/2
0
0x287B/1
This parameter setting brings the motor to a standstill.
The deceleration n = 0 selection is parameterised in the following
parameter: 0x2897:002
Curve (a): deceleration parameterised in
eration STO after n=0 starts if the speed is lower than the tolerance win-
dow of the motor speed parameterised in
ance window (n=0).
After the stopping time parameterised in
ping time for SS1 and SS2 has elapsed, the inverter switches to STO.
Curve (b): If the deceleration ramp is set too long, it is switched to STO
after the stopping time has elapsed. In this case shown, the motor coasts
to a stop.
SS2,
Safety functions
Safe Stop 1 (SS1)
STO
STO
t
0x2897:0020x2897:002, decel-
0x287B:0010x287B:001, toler-
0x2894:0010x2894:001, stop-
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