Omron DEVICENET SAFETY - 03-2008 Operation Manual page 137

Calculated Values of PFD and PFH
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
DST1-XD0808SL-1
IMPORTANT The proof test interval of the DST1-MRD08SL-1 must not exceed 0.5 years because the mainte-
nance interval for the relay contacts must not exceed a period of 6 month to satisfy safety cate-
gory 4 in accordance with EN 954-1.
A-2-2 Calculated PFH Values
Model
DST1-ID12SL-1
DST1-MD16SL-1
DST1-MRD08SL-1
DST1-XD0808SL-1
116
Proof test interval (years)
0.25
0.5
1
2
0.25
0.5
1
2
0.25
0.5
0.25
0.5
1
2
PFH
2.00E-10
2.00E-10
4.20E-09
2.00E-10
Appendix 2
PFD
2.21E-07
4.39E-07
8.76E-07
1.76E-06
2.22E-07
4.40E-07
8.77E-07
1.76E-06
4.70E-06
9.54E-06
2.22E-07
4.40E-07
8.77E-07
1.76E-06