BBH SCU Series, Installation Manual

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10
Safety-related characteristics
HB-37500-810-11-16F-EN SCU Installation Manual - Master and Slaves - SARC Page 100 of 303
Status: 09.06.2022
10.2.2.2. General diagnostic measures for encoder interface
For fault detection in the sensor system the SCU series (SDU modules) has a number of
diagnostic measures implemented, depending on the chosen encoder type or its
combination. These are automatically activated when choosing the encoder type.
With respect to their type and effectiveness diagnostic measures can generally be
classified using the following table:
Diagnoses for sensors for position and/or speed detection:
Measure DC Note Use
Cross-comparison of input
signals with immediate and
intermediate results in the logic
(L) and temporal as well as logic
program sequence monitoring
and detection of static failures
and short circuits (for multiple
inputs/outputs). 99% Only to be used for:
- dual-channel sensor
systems (2 separate
sensors),
- the dual channel partial
system of single channel
sensors (incremental
encoder)
- Diagnose for the single
and dual channel partial
system of especially
suitable sensor systems
(SIN/COS-encoder,
resolver)
- Dynamic operation /
no standstill monitoring
Monitoring of 2-channel
sensor systems or the
corresponding partial
system of sensors for
dynamic operation
Not to be used for
standstill monitoring!
Cross-comparison of input
signals without dynamic test 80-
95% DC depends on the
frequency of the dynamic
condition, i.e. standstill or
movement, as well as on
the quality of the
monitoring measure
(80
– 90 % for
incremental encoder, 95
% for SIN/COS-encoder)
Monitoring of 2-channel
sensor systems or the
corresponding partial
system of sensors for
non-dynamic operation
To be used especially for
standstill monitoring!
Monitoring of some features of
the sensor (response time, the
area of analog signals, e.g.
electric resistance, capacity) 60% Diagnose of specific
features of sensors, only
to be used for speed and
position sensors as per
chapter 4.2.2.4
Monitoring of the single-
channel partial system in
single-channel sensor
systems