Ex p Control unit
APEX
mv
Safety
Rev. 0
01-37A2-7D0005_MV_Manual_Exp-Control-Unit_2021005_0_en.docx
Page 17 of 80
Safety parameters
THE FOLLOWING SAFETY PARAMETERS ARE WITHOUT OPTIONAL
SENSORS.
The optional sensors must be considered to determine the total
failure rate!
The safety parameters may be derived from the
documentation on the optional sensors used.
Safety parameters according to IEC/EN 61508 / DIN EN ISO 13849-:
SIL = 2
Performance Level: = d
PFH
sys
= (PFH_S+PFH_C) = 1.70E-08
HFT = 1
SFF
sys
= 92.85 %
MTTFd = 76 Yr
DC = 88.78 %
Device type B (complex equipment)
Interval of retests = 1 year
Category 3
Reaction time
The reaction time of the Ex p control unit to safety-relevant functions without
specific user delay times is smaller than 2 seconds.
With the Ex p control unit it is possible to set a delay time for pressure
fluctuations below the minimum pressure.
This results in a delay time of
T
Reaction
=
T
Control
+ T
Delay
T
Reaction
=
Time required by the Ex p control unit APEX to react to a safety-
relevant function
T
Control
=
Internal time required by the Ex p control unit to recognise the
safety-relevant triggering. < 2 seconds
T
Delay
=
Adjustable delay time for safety-relevant triggering which is
added to the reaction time T
Control
.
Residual risk
Residual risks may arise from:
Errors in project planning
Errors in operating
Errors in wiring
