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Rockwell Automation Publication 1756-RM001I-EN-P - May 2012
Appendix C
PFD Calculations for a SIL 2 System
Determine Which PFD Values To Use
Each of the PFD calculated values provided in this manual is based on the
configuration that the module can be used in, that is 1oo1 or 1oo2.
•
Communication and controller communication modules have PFD values
specific to use in a 1oo1 configuration.
•
Input or output modules have PFD values specific to use in a 1oo2
configuration.
1-Year PFD Calculations
The PFD calculations in this table are calculated for a 1-year proof test interval
and are specific to ControlLogix system components.
IMPORTANT
You are responsible for determining which PFD values provided are
appropriate for your SIL 2-certified system. Determine which values to use
based on the modules used your system and the system configuration.
Table 10 - PFD Calculations - 1-year for ControlLogix Component
Cat. No.
(1)
(2)
Description
61508
(2010)
Mean Time Between
Failure (MTBF)
(9)
λ
(10)
Calculated PFD
1oo1
Architecture
1oo2
Architecture
1756-A
XX
/B
(3)
ControlLogix chassis
22,652,009
4.415E-08
9.6901E-06
x
1756-A4LXT
ControlLogix-XT chassis
1,069,120
9.353E-07
2.0531E-04
x
1756-A5XT/B
ControlLogix-XT chassis
734,420
1.362E-06
2.9888E-04
x
1756-A7LXT/B
ControlLogix-XT chassis
27,628,178
3.619E-08
7.9448E-06
x
1756-A7XT/B
ControlLogix-XT chassis
1,081,600
9.246E-07
2.0294E-04
x
1756-PB72/C
ControlLogix DC power supply
31,561,095
3.168E-08
6.9548E-06
x
1756-PA72/C
ControlLogix AC power supply
18,336,146
5.454E-08
1.1971E-05
x
1756-PA75/B
ControlLogix AC power supply
18,693,044
5.350E-08
1.1742E-05
x
1756-PA75R
ControlLogix AC redundant power supply
(8)
1,412,877
7.078E-07
1.5536E-04
x
1756-PB75/B
ControlLogix DC power supply
15,675,475
6.379E-08
1.4003E-05
x
1756-PB75R
ControlLogix DC redundant power supply
1,736,020
5.760E-07
1.2644E-04
x
1756-PAXT/B
ControlLogix-XT AC power supply
18,693,044
5.350E-08
4.0122E-08
x
1756-PBXT/B
ControlLogix-XT DC power supply
1,855,360
5.390E-07
1.1831E-04
x
1756-PC75/B
(4)
ControlLogix DC power supply
5,894,836
1.696E-07
3.7236E-05
x
1756-PH75/B
ControlLogix DC power supply
2,119,520
4.718E-07
1.0356E-04
x
1756-PSCA
(4)
ControlLogix redundant power supply adapter
45,146,727
2.215E-08
4.8619E-06
x
1756-PSCA2
ControlLogix redundant power supply adapter
38,461,280
2.600E-08
5.7070E-06
x
1786-RPFS
ControlNet fiber repeater - short
26,461,760
3.779E-08
8.2950E-06
x
1786-RPFM
ControlNet fiber repeater - medium
16,697,862
5.989E-08
1.3145E-05
x
1786-RPFL
ControlNet fiber repeater - long
5717227
1.749E-07
3.8393E-05
x
1786-RPCD
ControlNet hub repeater
28,654,080
3.490E-08
7.6603E-06
x
1756-L61/B
ControlLogix 2 MB controller
1,000,053
9.999E-07
2.1949E-04
x
Summary of Contents for 1756-L6 Series
Page 24: ...24 Rockwell Automation Publication 1756 RM001I EN P May 2012 Chapter 1 SIL Policy Notes ...
Page 76: ...76 Rockwell Automation Publication 1756 RM001I EN P May 2012 Chapter 6 FLEX I O Modules Notes ...
Page 126: ...126 Rockwell Automation Publication 1756 RM001I EN P May 2012 Appendix D Checklists Notes ...
Page 133: ...Allen Bradley Motors ...