Fail-Safe Functions - Siemens SINAMICS G120 Operating Instructions Manual

8.18

Fail-safe functions

Overview
Warning
Installation and protection level of Control Units in fail-safe systems
All installation areas for Control Units with fail-safe functions as well as outside installed
components of the according fail-safe system, if correctly installed, must comply with the
minimum protection level of IP54 [see EN 60529 (IEC 60529)].
Change of Control Units with fail-safe functions
When carrying out a swap of Control Units, it is not allowed to replace a Control Unit with
fail-safe functions with a Standard Control Unit. Replacing a Control Unit with fail-safe
functions with a Standard Control Unit disables all fail-safe functions that have been
implemented and therefore can lead to personal injury and damage to the machine. A
replacement of fail-safe components with standard components has to be considered as a
completely new application and re-commissioned as such.
Dimensioning of the Motor
If regenerative loads occur in the application, the motor must be dimensioned so that its slip
in super-synchronous operation always remains below the rated slip.
Dimensioning of the Motor holding brake
The motor holding brake must be dimensioned that in case of a fault the complete drive can
be braked to zero from any possible operational speed. If no holding brake is present, the
machine manufacturer must adopt other suitable measures of protection against motion after
the power to the motor has been cut (e.g. to protect against sagging loads).
Regenerative load with SLS
With the fail-safe functions "safely limited speed" (SLS) and "safe stop 1" (SS1) operation
with permanent regenerative loads is not permitted.
Note
In order to verify the parameters for the fail-safe functions, an acceptance test must always
be carried-out after commissioning, reset and also when changing a completely backed-up
data set of the parameters for the fail-safe functions. This acceptance test must be
appropriately logged and documented. For more details refer to Section "Acceptance Test
and Acceptance Log" In Chapter "Commissioning".
Control Units CU240S
Operating Instructions, 11/2006, A5E00766042B AA
Functions
8.18 Fail-safe functions
8-99