Lenze i950 Series, Manual

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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
( 0x2897:001 0x2897:001 ).
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. 0x287B:001 0x287B:001, tolerance window (n=0) .
The deceleration ramp can be parameterised and monitored for the stop func-
tion SS1.
SS1-t
0x2897:001 = 0 (STO after stopping time)
SS1-t
0x2897:001 = 1 (STO at n = 0)
n
t
0
STO
SS1
0x2894/1
0x287B:001
b
a
n
t
0
SS1
STO
STO
0x2894/1
0x287B/1
0x2897/2
a
b
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) has
elapsed. The switching operation is triggered irrespective of whether the
motor is at standstill or not!
This parameter setting brings the motor to a standstill.
The deceleration n = 0 selection is parameterised in the following
parameter:
0x2897:002
Curve (a): the motor comes to a standstill within the parameterised
stopping time. Curve (a): deceleration parameterised in 0x2897:002 0x2897:002, decel-
eration STO after n=0 starts if the speed is lower than the tolerance win-
dow of the motor speed parameterised in 0x287B:001 0x287B:001, toler-
ance window (n=0) .
After the stopping time parameterised in 0x2894:001 0x2894:001, stop-
ping time for SS1 and SS2 has elapsed, the inverter switches to STO.
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. 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.
Notes on how to set the stopping time
When setting the stopping time
0x2894:001 0x2894:001,stopping time for SS1 and SS2 ,
observe the following dependency:
1
.
If an encoder is available, a speed is calculated from the encoder data.
•
In 0x2897:001 0x2897:001 , selection "1": STO at n = 0, a waiting time
0x2897:002 0x2897:002, deceleration STO after n=0 can be set which defines when the
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 0x2894:001 0x2894:001, stopping time for SS1 and SS2
0.5 s monitored by the safety system must be parameterised higher than the stopping
time parameterised in the inverter.
Safety functions
Safe Stop 1 (SS1)
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