Safety Integrated Extended Functions
6.13 Reliable actual value acquisition with the encoder system
Safety Integrated
116 Function Manual, 05/2010, A5E03264275A
Encoder types
Incremental encoders or absolute encoders can be used for safe acquisition 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 1 and 2 encoder systems
In systems with encoders with SINAMICS Safety Integrated (1 and 2 encoder systems), for
safe actual value acquisition only encoders with sin/cos 1 Vss signals to the SINAMICS
Sensor Modules SME20/25, SME120/125 and SMC20 are permitted which fulfill the
following conditions:
1. The encoders must contain purely analog signal processing and creation. This is
necessary to be able to prevent the A/B track signals with valid levels from becoming
static ("freezing").
2. A failure mode and effects analysis (FMEA) must be carried out for the fixation of the
encoder onto the motor shaft or the linear drive. The result should incorporate exclusion
of the failure "Loosening of encoder fixation so that encoder no longer reports movement
correctly" (see IEC 61800-5-2, table D.16).
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.
Also certain motors with and without DRIVE-CLiQ connection can be used for Safety
Integrated functions; see http://support.automation.siemens.com/WW/view/de/33512621
NOTICE
Basic absolute encoders (e.g. ECI, EQI), which offer an EnDat interface with additional
sin/cos tracks but operate according to an inductive measuring principle internally, are not
permitted until their suitability for SINAMICS Safety Integrated has been determined.
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