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This table shows a summary
of sources of error related
to pneumatics, taken from
DIN EN ISO 13849-2. Under
certain conditions, it is possible
to exclude faults.
The requirements for excluding
a fault are described in detail in
DIN EN ISO 13849-2. Faults must
be examined and evaluated in
the context of each application
to establish whether the fault
has a dangerous effect on the
safety function. Depending on
the construction principle and
the design of components,
different results may arise for
different applications; in other
words, a specific product may be
suitable for one application but
not for another. The design
engineer for the installation is
responsible for checking this.
Defining the diagnostic coverage (DC)
Change to the response times
Non-switching/
not switching back
Auto-switching
Leakage
Change to the leakage
over a long period of use
Cracking of the housing/
connecting piece/tubing
Change to the flow rate
without assistance (adjustable)
Change to the flow rate
without assistance (fixed)
Change to the behaviour
without assistance
For proportional flow valves:
unintentional change to the
setting value
Automatic change to the
adjusting device
Directional control valves
Shut-off/non-return/quick
exhaust/shuttle valves
Flow control valves
Pressure limiting valves
Pipelines
Tubing lines
Connecting components
Pressure intensifier and
pressure medium converter
Filters
Lubricators
Silencers
Energy storage device
and reservoir
Sensors
Logic elements (AND/OR)
Delay elements
Transformers (pressure switch,
position switch and amplifier)
Cylinders
Products
Sources of error