Safety engineering
Safety functions
Safe stop 1
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EDS94AYAE EN 6.0
1.3.4 Safe stop 1
1.3.4.1 Description
Safe Stop 1 / SS1
This function corresponds to a "Stop 1" according to EN 60204.
The function monitors the reaching of the speed n = 0 (C15310) within an adjustable
stopping time (C15305). The speed is calculated from the encoder data (safe speed
measurement). Without encoder the function evaluates the speed status n = 0 from the
standard device. For this, the monitored stopping time parameterised in the safety module
must be 0.5 s longer than the stopping time in the controller.
When the stopping time (t2) has expired, the motor power supply is safely interrupted
(STO) immediately. The motor cannot create a torque and thus no dangerous movements
of the drive. If standstill has not been achieved, an additional error message is triggered.
Depending on the SS1 mode (C15306), the drive can also be switched off safely (STO)
directly after the zero speed has been reached. This causes reduced cycle times. C15307 can
be used to parameterise an additional deceleration time, e.g. for the application of a
holding brake.
Additional measures, e.g. mechanical brakes are needed against movements caused by
external force. The time for a brake to be applied must be considered when defining the
stopping time.
A restart is only possible after the stopping time has expired completely (is valid up to
SM301 V1.2 and from SM301 V1.3 if C15306 SS1 mode = "STO after stopping time"). If the
parameter SS1 mode = "STO at n=0" (from SM301 V1.3), the restart can be executed after
the transition to the STO state.
From SM301 V1.4 onwards, deceleration ramp monitoring can be parameterised.
Depending on the parameterised stopping time, a monitoring ramp is calculated. ( 64)