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SAFETY MANUAL
4.2 ENGINEERING CHECKLISTS
4.2.1 I/O Architecture Checklist
Description
Reference
Has the PST E been established 1.3.3
and
2.2.1.3
What is the PST E
Has the fault detection time for the system
been established
3.2.2
and
Error!
Refere
nce
source
not
found.
What is the fault detection time
Where the fault detection time is greater than
the PST E, does the safety-related I/O
configuration provide a fail-safe
configuration
If not, the system topology shall be discussed
with the client to ensure that the system
implementation is safe.
If a probability of failure on demand has been
specified, has this been met
Do the selected architectures provide
solutions where there is no single power
source or distribution point of failure that
could lead the system to fail to function safely
when required
Have sensor fault conditions been taken into
account
3.14
3.3
For each of the I/O signal types, do the I/O
modules provide the correct characteristics
and behaviour for the intended sensor or
actuator (including minimum and maximum
load requirements)
If not, have additional interfacing elements
been included to ensure that the effective
signal is compatible with the selected module
type
Are the selected I/O module types compatible
with the required I/O architecture
Is the safety-accuracy adequate for the
application
3.2.1
3.2.3
Doc Number P8094
Issue 14 September 2003 Page 75 of 67