BBH SCU Series, Руководство по установке

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10
Safety-related characteristics
HB-37500-810-11-16F-EN SCU Installation Manual - Master and Slaves - SARC Page 109 of 303
Status: 09.06.2022
generated independently from each other and Common-Cause faults
can be ruled out. Evidence of the mechanical design, e.g. fastening
of the code disc on the shaft, must also be provided. Encoders with
proven safety related characteristics should preferably be used.

When using compact encoders with internal dual-channel structure,
such as e.g. SSI + incremental/SinCos, you must strictly follow the
instructions of the manufacturer concerning safety related
characteristics, diagnostic measures, mechanical connection and
measures concerning the electric power supply. The safety level of
the encoder must at least meet the intended safety level of the
overall arrangement. Encoders with proven safety related
characteristics should preferably be used.
The SCU- module generally detects the following faults in the
external encoder system:
• Short-circuits between safety relevant signal lines
• Interruptions in safety relevant signal lines
• Stuck at 0 or 1 on one or all safety relevant signal lines
Each encoder type has further specific diagnoses for fault detection
in the external encoder system assigned. The following list sows
the respective diagnostic measures for the individual encoders,
together with the limiting parameters.
SAFETY NOTE • The diagnostic measures obviously have tolerances because of
measuring inaccuracies. These tolerances must b e accounted for
in the safety related assessment.
• The limiting values for the corresponding diagnostic measures
are partly parametrizable or fixed. The diagnostic coverages
resulting from this must be assessed in relation to the application
and included in the safety related overall assessment.