Siemens SINAMICS S120 Commissioning Manual page 232

Commissioning
4.10 Safety Integrated commissioning
Safe, encoderless actual value acquisition is based on the measurement of current and
voltage variables, which can influence the following functions. This does not result in unsafe
states. However, this fault can be expected to have a negative impact on availability.
Note
Irregular operating states
Note that in irregular operating states (e.g. stalled motor), the converter can fail with safety
faults. However, under no circumstances is an unsafe state reached.
● Current limiting of the power unit
When the current limitation of the power unit responds, a fault of the encoderless safe
actual value acquisition and a consequent stop response can be expected.
Note
When engineering the drive and when parameterizing the current and torque limits, it
must be ensured that the power unit current limiting does not respond.
● Operation with pulling loads
It is not permissible that the converter is forced into regenerative operation as a result of
external forces.
Note
If a coupled drive comprises an electric drive that motors and one that regenerates (e.g. a
test stand), and the speeds of both drives are safely monitored, safety functions without
encoder can be used. This is because in the case of a fault, the motoring drive
recognizes when a limit value is violated. If, in this example, the motoring drive is an
internal combustion engine, which is not safely monitored, it is not permissible to use
safety functions without encoder for the braking drive.
Winders with a motoring and a braking drive can be assessed in the same way (both
drives are monitored).
● Motor data identification
When using the measuring functions (stationary and rotating measurement) to determine
the motor data, then it can be assumed that the encoderless safe actual value acquisition
will have an error.
Note
The motor data identification should always be performed before commissioning the
Safety Integrated extended functions.
232
Commissioning with Startdrive
Commissioning Manual, 11/2017, 6SL3097-4AA10-0BP1