12
Functional safety
Integrated Safety Technology
Operating Instructions – MOVIMOT
®
flexible
409
12.2.5
Drive safety functions
The following drive-related safety functions can be used:
•
STO
(Safe Torque Off according to EN 61800-5-2) by disconnecting the STO in-
put.
If the STO function is activated, the frequency inverter no longer supplies power to
the motor for generating torque. This drive safety function corresponds to a non-
controlled stop according to EN 60204-1, stop category 0.
The STO input must be disabled by a suitable external safety controller/safety re-
lay.
The following figure shows the STO function:
v
t
t
1
2463228171
v
Speed
t
Time
t
1
Point of time when STO is triggered
Disconnection range
•
SS1(c) (SS1-t)
(safe stop 1, with time control according to EN 61800-5-2) by
means of suitable external control (e.g. safety relay with delayed disconnection).
The following sequence is mandatory:
– Decelerate the drive using an appropriate deceleration ramp specified via set-
points.
– Disconnect the STO input (= triggering the STO function) after a specified
safety-related time delay.
This drive safety function corresponds to a controlled stop according to
EN 60204‑1, stop category 1.
The following figure illustrates the SS1(c) function (SS1-t):
v
t
t
1
t
t
2
2463226251
v
Speed
29128668/EN – 12/2019
