Appendix 2: Calculated Values Of Pfd And Pfh; A-2-1 Calculated Pfd Values; A-2-2 Calculated Pfh Values - Omron DeviceNet DST1 Series Operation Manual

Appendix 2: Calculated Values of PFD and PFH

Calculated values of PFD and PFH of the DST1-series Safety I/O Terminals are given in
the following tables. These values must be calculated for the overall devices within the
system to comply with the SIL level required for application.
A-2-1 Calculated PFD Values
Model
DST1-ID12SL-1
DST1-MD16SL-1
DST1-MRD08SL-1
IMPORTANT The proof test interval of the DST1-MRD08SL-1 must not exceed 0.5 years
A-2-2 Calculated PFH Values
Model
DST1-ID12SL-1
DST1-MD16SL-1
DST1-MRD08SL-1
Appendix 2: Calculated Values of PFD and PFH
Proof test interval (years)
because the maintenance interval for the relay contacts must not exceed a period
of 6 month to satisfy safety category 4 in accordance with EN 954-1.
PFH
8.75E-10
1.11E-09
5.24E-09
0.25
0.5
1
2
0.25
0.5
1
2
0.25
0.5
PFD
9.58E-07
1.92E-06
3.83E-06
7.66E-06
1.21E-06
2.41E-06
4.82E-06
9.64E-06
5.81E-06
1.18E-05
A-13