Kübler Sendix 58 FS2 Instructions D'utilisation page 40

Before switching the facility off, the absolute position value
must be saved by the encoder evaluation unit. When switch-
ing it back on, the encoder evaluation unit must compare the
saved value with the absolute value newly measured after
switching on. If both values are identical, the position is still
safe. If the position values are not identical, the position is not
safe and must be newly verified.
3.4.2.3 Functional Specification
Incremental value
The incremental sin-cos signals are safety-assessed. The
monitoring of the unit circle allows achieving a diagnostic cov-
erage of 99 %. The function can be examined at any time.
This means that, for an encoder resolution of 2048 sine-co-
sine periods, the validity can be checked by the encoder eval-
uation unit 2048 times per revolution. With a tolerance of the
sin²(x) + cos²(x) function of ± 0.5, the max. possible error path
will be 10 % of a signal period (36° electrically).
Typical limits and tolerances see chapter
Technical Data [} 43].
The sine-cosine signal alone does not allow realizing abso-
lute safety sub-functions and a safe rotation direction can
achieve at the maximum SIL2. Additional signal paths are re-
quired to be able to use both to a full extent up to SIL3.
3.4.2.4 Encoder Evaluation
Only operate the encoder together with a safe encoder evalu-
ation unit / controller. Only this equipment can monitor the
proper function and achieve a safe system.
40 - EN
Monitoring in the encoder evaluation unit must be carried out
directly on the encoder signal. Previous processing, e.g. in-
terpolation, is not allowed.
The encoder cannot prevent the automated restarting of the
facility after a malfunction. If this is necessary, it must be en-
sured by the encoder evaluation unit.
The technical requirements for the encoder evaluation unit
are described in chapter Annex [} 60].
3.4.2.5 Encoder Mounting
The mechanical interface has been dimensioned so that fail-
ure exclusion can be assumed as a result of overdimension-
ing and / or diagnosis.
The connection of the encoder and the drive unit must be as-
sessed from a safety-related point of view. This relates both
to the connection with the rotary element (shafts connection)
and to the stationary section (stator connection).
To this purpose, Kübler provides the corresponding mechan-
ical interfaces.
Shaft connection:
• Solid shaft with feather key
• Solid shaft with flat
• Hollow shaft with clamping ring
• Tapered shaft with central fastening
Stator connection:
• The provided tether arms, stator couplings and torque stops
are assessed from a safety-related point of view.
BA Sendix® 58xxFS2 / 58xxFS3 - R60049.0009 - 04