Publication 1794-RM001G-EN-P - December 2011
SIL Policy
1-11
Table 1.4 shows an example of a PFD calculation for a safety loop involving
two DC input modules used in a 1oo2 configuration and a DC output module.
1794-IE4XOE2XT
4 Input/2 Output Analog Combo Module
11,800,802
8.47E-08
5.99E-10
1794-IE8XT
8 Input analog Module
14,041,000
7.12E-08
5.03E-10
1794-OE4XT
4 Output Analog Module
11,381,744
8.79E-08
6.22E-10
1794-IF2XOF2IXT
2 Input/2 Output Isolated Analog Combo Module
6,317,918
1.58E-07
1.13E-09
1794-IF4IXT
4 Isolated Input Analog Module
7,297,140
1.37E-07
9.75E-10
1794-IF4ICFXT
4 Isolated Input Analog Module
7,297,140
1.37E-07
9.75E-10
1794-OF4IXT
4 Isolated Output Analog Module
5,493,902
1.82E-07
1.30E-09
1794-IJ2XT
2 Ch. Frequency Counter Module
11,714,128
8.54E-08
6.04E-10
1794-IRT8XT
8 TC/RTD Input Analog Module
8,204,792
1.22E-07
8.66E-10
(1)
MTBF measured in hours.
(2)
Calculated using field-based values for components
(3)
λ
= Failure Rate = 1/MTBF
Table 1.3 FLEX I/O Product Probability of Undetected Dangerous Failure per Hour (PFH) Calculations (T
1
= 1
yr
)
Catalog Number
Description
Mean Time
Between Failure
(MTBF)
(1)
λ
(3)
Calculated PFH
1oo2 architecture
Table 1.4
Catalog Number:
Description:
MTBF:
Calculated
1oo2 PFD:
1794-ACNR15
ControlNet Dual Media
Adapter 1.5
3,259,605
1.56E-06
1794-IB16
24V DC Input Module
6,409,846
4.34E-06
1794-IB16
24V DC Input Module
6,409,846
4.34E-06
1794-OB16
24V DC Output Module
4,284,857
9.62E-06
1794-OW8
Relay Output Module
1,312,973
1.20E-06
1756-L63B
1
ControlLogix Controller
2,460,065
2.33E-04
1756-CNB
ControlNet Bridge Module
3,596,087
1.15E-04
1756-CNB
ControlNet Bridge Module
3,596,087
1.15E-04
Total PFD calculation for a safety loop consisting of these products:
3.70E-04
1 See Publication
for more information.
Содержание FlexLogix 1794
Страница 1: ...FLEXI OSystemwithControlLogixforSIL2 Catalog Number Bulletin 1794 Reference Manual AB Drives ...
Страница 18: ...Publication 1794 RM001G EN P December 2011 1 14 SIL Policy Notes ...
Страница 22: ...Publication 1794 RM001G EN P December 2011 2 4 ControlLogix Communications ...
Страница 42: ...Publication 1794 RM001G EN P December 2011 3 20 FLEX I O Modules Notes ...
Страница 44: ...Publication 1794 RM001G EN P December 2011 4 2 General Requirements for Application Software Notes ...
Страница 46: ...Publication 1794 RM001G EN P December 2011 5 2 Technical SIL2 Requirements for the Application Program Notes ...
Страница 56: ...Publication 1794 RM001G EN P December 2011 A 10 Failure Estimates Notes ...
Страница 59: ...AB Drives ...