Siemens SINAMICS S120 Function Manual page 163

You can implement failsafe detection of slip on the encoder shaft or a broken motor-encoder
shaft by checking the plausibility of the acquired safety-relevant actual value with respect to
the expected setpoint. If the actual value does not lie within a configurable tolerance
bandwidth around the setpoint within a defined time, then it can be assumed that there is
either slip - or that there is a broken connection between the encoder and the motor. You
must ensure this monitoring functionality in the safety user program according to SIL 2 or
PL d.
It should be noted that the machine manufacturer has sole responsibility for the fulfillment of
the above-described requirements. Information on the internal realization of the encoder
must come from the encoder manufacturer. The FMEA must be created by the machine
manufacturer.
Siemens motors with and without DRIVE-CLiQ connection, which can be used for Safety
Integrated functions, are listed under:
Siemens motors for Safety Integrated
(https://support.industry.siemens.com/cs/ww/en/view/33512621)
For these motors, the encoder mounting on the motor shaft can be considered to be safety
relevant, and faults associated with an encoder becoming loose ruled out.
Note
Basic absolute encoders with EnDat interface and additional sin/cos tracks
Basic absolute encoders (e.g. EQI) that offer an EnDat interface with additional sin/cos
tracks, but operate according to an inductive measuring principle internally, are not permitted
for SINAMICS Safety Integrated.
Note
Encoder types for SINAMICS HLA
The following encoder types are permissible for SINAMICS HLA:
• Single-encoder systems
– DRIVE-CLiQ encoder with safety capability
– sin/cos encoder connected via SME20/25, SME120/125 or SMC20 (1 V
• 2-encoder systems
– Encoders with DRIVE-CLiQ connection
– sin/cos encoder connected via SME20/25, SME120/125 or SMC20 (1 V
– HTL/TTL encoder connected via SMC30 (not in connection with SINUMERIK)
– TTL encoder connected via the onboard interface of the HLA module (not in
Safety Integrated
Function Manual, 12/2018, 6SL3097-5AR00-0BP1
analog signal processing)
analog signal processing)
connection with SINUMERIK)
Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
, pure
PP
, pure
PP
161