Siemens SINAMICS S120 Function Manual page 96

Safety Integrated Extended Functions
5.12 Safe actual value acquisition
Figure 5-13
Encoder types
Incremental encoders or absolute encoders can be used for safe detection of the position
values on a drive.
Safe actual value acquisition relies on redundant evaluation of the incremental channels A/B
that supply sin/cos signals of 1 Vpp.
The absolute position values can be transferred via the serial EnDat interface or an SSI
interface to the controller.
Encoder types for a single-encoder system
In single-encoder systems, encoders with photoelectric sampling only are permitted for safe
actual value acquisition. These optical encoders must supply sin/cos signals of 1 Vpp on the
incremental channels A/B.
Note
Basic absolute encoders (e.g. ECI, EQI) that offer an EnDat interface with additional sin/cos
tracks, but operate according to an inductive measuring principle internally, are not permitted
for single-encoder systems.
96
Example of an S120 two-encoder system on a rotary axis
Function Manual, (FHS), 11/2009, 6SL3097-4AR00-0BP0
Safety Integrated