Rockwell Automation T8094 8000 Series TMR System Safety Manual - Manual (Page 77)

SAFETY MANUAL
D oc N umber T8094
I ssue 27 – June 2013
Page 56 of 103
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 0
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?
3.13.4
Have sensor fault conditions been taken into
account?
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?
3.2.1
Is the safety-accuracy adequate for the
application?
If active and standby modules are to be
installed simultaneous, has allowance been
included for the effect on the accuracy?
3.2.3