Restrictions When Using Safety Functions - Siemens Sinamics G120 Function Manual

3.5

Restrictions when using safety functions

Not permitted: Operation with pulling loads
It is not permissible that you use the encoderless safety functions in applications involving
pulling loads, e.g. in hoisting gear, elevators and unwinders.
Death or severe injury as a result of an undesirably accelerating load
The encoderless actual value sensing does not identify all faults and errors in the closed-loop
motor control. As a consequence, encoderless safety functions, cannot identify whether a
pulling load undesirably accelerates the drive due to a fault in the closed-motor control.
● Never use safety functions with encoderless speed monitoring for drives with pulling loads.
What options are there for monitoring the speed for pulling loads?
● You can implement speed monitoring in machines with pulling loads in one the following
ways:
– Select a drive with safety functions that use an encoder, for example SINAMICS S120.
– Implement the speed monitoring in the higher-level control by using a suitable measuring
● Coupled electric drives, e.g. test stands and winders/unwinders comprise a driving and a
driven drive. Using the extended functions in the drive that has a driving function in a
coupled drive system. In the case of a fault, the drive with the driving function identifies
when a limit value is violated.
Not permitted: Motors with different pole pair numbers
Death or serious injury due to unexpected high speeds
If you use the "Drive data set" function to switch over motors with different pole pair numbers,
then the calculated, safety-related speed differs from the mechanical speed of the motor shaft.
As a consequence, the motor shaft can accelerate above the configured monitoring limits of
the safety function. This can result in death or severe injury.
● When using the "drive data set" function, only switch between motors with the same pole
Monitoring the speed of motors with different pole pair numbers
Implement the speed monitoring in the higher-level control by using a suitable measuring
system to acquire the velocity or speed.
Safety Integrated - SINAMICS G110M, G120, G120C, G120D and SIMATIC ET 200pro FC-2
Function Manual, 01/2017, FW V4.7 SP6, A5E34261271B AD
WARNING
system to acquire the speed/velocity.
WARNING
pair number.
3.5 Restrictions when using safety functions
Description
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