3.4 Preconditions when using the safety functions
Risk assessment
A risk analysis and assessment of the plant or machine is required before using the safety
functions integrated in the drive.
The risk analysis and assessment must verify the following:
● The safety function integrated in the drive is suitable as a protective measure to minimize
risks associated with the machine.
● The accepted probability of failure of the protective measure must be greater or equal to
the certified probability of failure of the safety function integrated in the drive.
Certification (Page 370)
Motors and control modes
You can use the basic functions without any restrictions:
● For all control modes: U/f control and speed control with and without encoder
● With synchronous and induction motors
● For group drives, which involves the simultaneous operation of several motors connected
to one inverter
It is only permissible that you use the extended functions under the following preconditions:
● With induction motors for all control modes
● With SIEMOSYN synchronous motors only with U/f control
● For group drives
Encoderless safety functions
The safety functions integrated in the drive do not use an encoder.
"Encoderless" means the following:
● You do not require an encoder to use the safety functions integrated in the drive.
● If the inverter has an encoder connection, the inverter uses the encoder signal to control
(closed loop) the motor. The safety functions ignore the encoder signal.
Taking into account the slip of induction motors
The speed of the motor shaft is relevant for the functional safety in or on a machine. However,
the extended functions monitor the electrical speed of the motor against the limit values that
have been set.
If you use encoderless safety functions with an induction motor, you must take into account
the motor slip when setting the speed monitoring.
Description
3.4 Preconditions when using the safety functions
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
26 Function Manual, 01/2017, FW V4.7 SP6, A5E34261271B AD
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