Pepperl+Fuchs K-LB Series User manual

ISO9001
3
Functional Safety
Surge Protection Barriers
K-LB-*.*, F*-LB-I, P-LB-*.*.*
Manual

With regard to the supply of products, the current issue of the following document is applicable:
The General Terms of Delivery for Products and Services of the Electrical Industry, published by the Central
Association of the Electrical Industry (Zentralverband Elektrotechnik und Elektroindustrie (ZVEI) e.V.) in its most
recent version as well as the supplementary clause: "Expanded reservation of proprietorship"
Worldwide
Pepperl+Fuchs Group
Lilienthalstr. 200
68307 Mannheim
Germany
Phone: [phone] - 0
E-mail: [e-mail]
North American Headquarters
Pepperl+Fuchs Inc.
1600 Enterprise Parkway
Twinsburg, Ohio 44087
USA
Phone: [phone]
E-mail: [email protected].com
Asia Headquarters
Pepperl+Fuchs Pte. Ltd.
P+F Building
18 Ayer Rajah Crescent
Singapore 139942
Phone: [phone]
E-mail: [email protected]
https://www.pepperl-fuchs.com

3
Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Contents
2021-09
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.1 Content of this Document . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
1.3 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2 Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.2 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.4 Standards and Directives for Functional Safety . . . . . . . . . . . . . . . . . . . 9
3 Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 System Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.2 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.3 Safety Function and Safe State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.4 Characteristic Safety Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.5 Useful Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4 Mounting and Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
5.1 Proof Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
6 Maintenance and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
7 Application Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
8 List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Contents
4
2021-09

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Introduction
2021-09
5
1 Introduction
1.1 Content of this Document
This document contains information for usage of the device in functional safety-related
applications. You need this information to use your product throughout the applicable stages
of the product life cycle. These can include the following:
•Product identification
•Delivery, transport, and storage
•Mounting and installation
•Commissioning and operation
•Maintenance and repair
•Troubleshooting
•Dismounting
•Disposal
The documentation consists of the following parts:
•Present document
•Instruction manual
•Manual
•Datasheet
Additionally, the following parts may belong to the documentation, if applicable:
•EU-type examination certificate
•EU declaration of conformity
•Attestation of conformity
•Certificates
•Control drawings
•FMEDA report
•Assessment report
•Additional documents
For more information about Pepperl+Fuchs products with functional safety,
see www.pepperl-fuchs.com/sil.
Note
This document does not substitute the instruction manual.
Note
For full information on the product, refer to the instruction manual and further documentation
on the Internet at www.pepperl-fuchs.com.

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Introduction
1.2 Safety Information
Target Group, Personnel
Responsibility for planning, assembly, commissioning, operation, maintenance,
and dismounting lies with the plant operator.
Only appropriately trained and qualified personnel may carry out mounting, installation,
commissioning, operation, maintenance, and dismounting of the product. The personnel must
have read and understood the instruction manual and the further documentation.
Intended Use
The device is only approved for appropriate and intended use. Ignoring these instructions
will void any warranty and absolve the manufacturer from any liability.
The device is developed, manufactured and tested according to the relevant safety standards.
Use the device only
•for the application described
•with specified environmental conditions
•with devices that are suitable for this safety application
Improper Use
Protection of the personnel and the plant is not ensured if the device is not used according
to its intended use.

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Introduction
2021-09
7
1.3 Symbols Used
This document contains symbols for the identification of warning messages and of informative
messages.
Warning Messages
You will find warning messages, whenever dangers may arise from your actions.
It is mandatory that you observe these warning messages for your personal safety and in order
to avoid property damage.
Depending on the risk level, the warning messages are displayed in descending order
as follows:
Informative Symbols
Action
This symbol indicates a paragraph with instructions. You are prompted to perform an action
or a sequence of actions.
Danger!
This symbol indicates an imminent danger.
Non-observance will result in personal injury or death.
Warning!
This symbol indicates a possible fault or danger.
Non-observance may cause personal injury or serious property damage.
Caution!
This symbol indicates a possible fault.
Non-observance could interrupt the device and any connected systems and plants,
or result in their complete failure.
Note
This symbol brings important information to your attention.

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Product Description
2 Product Description
2.1 Function
General
The surge protection barriers are used as modules positioned upstream in the circuit
from the corresponding electrical equipment. The surge protection barriers make it possible
to protect against overvoltages originating from various causes (lightning strikes, switching
processes, etc.). This is achieved by diverting the transient current and limiting the voltage
throughout the duration of the overvoltage surge. Various modules are available for protecting
2 or 4 conductors.
DIN Mounting Rail Modules
K-LB-*.*
This surge protection barrier provides low line-to-line clamping voltage and 500 V
line-to-ground clamping voltage for a protected device. The device can be used to protect
devices that have more than 500 V isolation-to-ground, such as intrinsic safety isolated
barriers, signal conditioners and most field devices.
K-LB-*.*G
This surge protection barrier provides a low line-to-line clamping voltage and line-to-ground
clamping voltage for the protected device. The device can be used to protect instruments
that have less than 500 V isolation-to-ground, such as zener barriers, standard I/O cards,
and some field devices.
Plug-In Modules
P-LB-*.*.*
This surge protection barrier is designed for use with the isolators of the K-System.
By simply snapping the device into a standard isolator, the isolator are safely protected.
The end digits of the model designation correspond to the protected terminals
of the respective isolator.
Field Mount Modules
F*-LB-I
This surge protection barrier provides 85 V line-to-line and 500 V line-to-ground clamping
voltage for the protected field device. The device also protects field devices that have less
than 500 V isolation-to-ground. The device is installed in an available conduit or cable gland
opening like those found on most process transmitters.

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Product Description
2021-09
9
2.2 Interfaces
The device has the following interfaces:
•Safety relevant interfaces: input and output
2.3 Marking
The stars replace a combination of characters, depending on the product.
2.4 Standards and Directives for Functional Safety
Device-specific standards and directives
Note
For corresponding connections see datasheet.
Pepperl+Fuchs Group
Lilienthalstraße 200, 68307 Mannheim, Germany
Internet: www.pepperl-fuchs.com
K-LB-*.**, F*-LB-I, P-LB-*.*.* Up to SIL 3
Functional safety IEC/EN 61508, part 2, edition 2010:
Functional safety of electrical/electronic/programmable electronic
safety-related systems (manufacturer)

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
3 Planning
3.1 System Structure
3.1.1 Low Demand Mode of Operation
If there are two control loops, one for the standard operation and another one for the functional
safety, then usually the demand rate for the safety loop is assumed to be less than once
per year.
The relevant safety parameters to be verified are:
•the PFDavg value (average Probability of dangerous Failure on Demand)
and the T1value (proof test interval that has a direct impact on the PFDavg value)
•the SFF value (Safe Failure Fraction)
•the HFT architecture (Hardware Fault Tolerance)
3.1.2 High Demand or Continuous Mode of Operation
If there is only one safety loop, which combines the standard operation and safety-related
operation, then usually the demand rate for this safety loop is assumed to be higher than
once per year.
The relevant safety parameters to be verified are:
•the PFH value (Probability of dangerous Failure per Hour)
•Fault reaction time of the safety system
•the SFF value (Safe Failure Fraction)
•the HFT architecture (Hardware Fault Tolerance)

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
2021-09
11
3.2 Assumptions
The following assumptions have been made during the FMEDA:
•The stress levels are average for an industrial environment and the environment is similar
to IEC/EN 60654-1 Class C (sheltered location) with temperature limits in the range
of the manufacturer's specifications and an average temperature of 40 ºC over a long
period. The humidity level is within manufacturer's rating.
•The listed failure rates are valid for operating stress conditions typical of an industrial field
environment similar to IEC/EN 60654-1 Class C with an average temperature over a long
period of time of 40 ºC. For a higher average temperature of 60 ºC, the failure rates must
be multiplied by a factor of 2.5 based on experience. A similar factor must be used
if frequent temperature fluctuations are expected.
•Failure rate based on the Siemens standard SN 29500.
•The control loop has a hardware fault tolerance of 0 and it is a type A device.
A SFF value for this device is not given, since this value has to be calculated
in conjunction with the connected field device, as described in the following section.
Application Information
The surge protection barrier and the connected device (field device, isolator or actuator) have
to be considered together. The PFDavg/PFH budget of the device categories in the entire
safety loop is, see Figure 5.1:
•Actuator (valve) 40 %
•Transmitter (sensor) 25 %
•Isolator 10 %
As an overview for SIL 2/SIL 3 safety loop this means:
SIL 2 SIL 3
PFH PFDavg PFH PFDavg
Total 10-6 10-2 10-7 10-3
Actuator (40 %) 4 x 10-7 4 x 10-3 4 x 10-8 4 x 10-4
Transmitter
(25 %) 2.5 x 10-7 2.5 x 10-3 2.5 x 10-8 2.5 x 10-4
Isolator (10 %) 10-7 10-3 10-8 10-4
Table 3.1 Overview PFDavg/PFH budget

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
3.3 Safety Function and Safe State
The surge protection barrier has to be considered in conjunction with the connected field
device. The safety function of the surge protection barrier is defined by the signals and settings
of the connected device (e. g. isolator, DCS input, output, field device).
Safety Function
The safety function of the device is to behave like a piece of copper wire, passing through
the process signal without being altered. In case of a 0/4 mA to 20 mA signal the maximum
additional loop current fault of the device is maximum ±1 % full scale.
Safe State
The safe state is defined as the device interrupting the input signal.
Reaction Time
The reaction time is < 20 ms.

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
2021-09
13
3.4 Characteristic Safety Values
The following tables contain no SFF characteristics, since this characteristics has
to be calculated with consideration of the connected field device.
DIN Mounting Rail Modules
K-LB-1.30, K-LB-2.30, K-LB-1.6, K-LB-2.6 (1oo1 structure)
Parameters Characteristics
Assessment type
and documentation FMEDA report
Device type A
Mode of operation Low demand mode or high demand mode
Safety function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 1AI AO DI DO
Safe state 1Iin < 3.6 mA
Signal line
interrupted
Iout < 3.6 mA
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Safety loop fault
detection 3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can be
detected
No fault detection
since < 3.6 mA is
safe state of the
safety loop
SC and LB detection
of the safety loop No fault detection
sd + su 0 FIT 16.1 FIT 8.1 FIT 16.1 FIT
dd 16.1 FIT 0 FIT 8.0 FIT 0 FIT
du 0 FIT 0 FIT 0 FIT 0 FIT
no effect 41.1 FIT 41.1 FIT 41.1 FIT 41.1 FIT
not part 0 FIT 0 FIT 0 FIT 0 FIT
total (safety function) 16.1 FIT 16.1 FIT 16.1 FIT 16.1 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
2002 years (1-channel device), 1001 years (2-channel device)
PFH 0 1/h 0 1/h 0 1/h 0 1/h
PFDavg for
T1 = 1 year 0 0 0 0
Table 3.2

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
K-LB-1.30G, K-LB-2.30G, K-LB-1.6G, K-LB-2.6G (1oo1 structure)
Parameters Characteristics
Assessment type
and documentation FMEDA report
Device type A
Mode of operation Low demand mode or high demand mode
Safety function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 1AI AO DI DO
Safe state 1Iin < 3.6 mA
Signal line
interrupted
Iout < 3.6 mA
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Safety loop fault
detection 3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can be
detected
No fault detection
since < 3.6 mA is
safe state of the
safety loop
SC and LB detection
of the safety loop No fault detection
sd + su 0 FIT 15.1 FIT 8.1 FIT 15.1 FIT
dd 15.1 FIT 0 FIT 7.0 FIT 0 FIT
du 0 FIT 0 FIT 0 FIT 0 FIT
no effect 22.1 FIT 22.1 FIT 22.1 FIT 22.1 FIT
not part 14.0 FIT 14.0 FIT 14.0 FIT 14.0 FIT
total (safety function) 26.9 FIT 26.9 FIT 26.9 FIT 26.9 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
2238 years (1-channel device), 1119 years (2-channel device)
PFH 0 1/h 0 1/h 0 1/h 0 1/h
PFDavg for
T1 = 1 year 0000
Table 3.3

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
2021-09
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Field Mount Modules
FN-LB-I, FS-LB-I, FP-LB-I (1oo1 structure)
Parameters Characteristics
Assessment type
and documentation FMEDA report
Device type A
Mode of operation Low demand mode or high demand mode
Safety function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 1AI AO DI DO
Safe state 1Iin < 3.6 mA
Signal line
interrupted
Iout < 3.6 mA
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Safety loop fault
detection 3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can be
detected
No fault detection
since < 3.6 mA is
safe state of the
safety loop
SC and LB detection
of the safety loop No fault detection
sd + su 0 FIT 6.95 FIT 0 FIT 6.95 FIT
dd 6.95 FIT 0 FIT 6.95 FIT 0 FIT
du 0 FIT 0 FIT 0 FIT 0 FIT
no effect 20.1 FIT 20.1 FIT 20.1 FIT 20.1 FIT
not part 10.1 FIT 10.1 FIT 10.1 FIT 10.1 FIT
total (safety function) 6.95 FIT 6.95 FIT 6.95 FIT 6.95 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
3085 years (all components of the device)
PFH 0.5 x 10-8 1/h 0.5 x 10-8 1/h 0.5 x 10-8 1/h 0.25 x 10-8 1/h
PFDavg for T1 = 1
year 2.19 x 10-5 2.19 x 10-5 2.19 x 10-5 1.09 x 10-5
Table 3.4

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
Plug-In Modules
P-LB-1.D.*, P-LB-1.F.* (1oo1 structure)
Parameters Characteristics
Assessment
type and
documenta-
tion
FMEDA report
Device type A
Mode of
operation Low demand mode or high demand mode
Safety
function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 14-wire
resistance
thermometer
(RTD)
3-wire
resistance
thermometer
(RTD)
Voltage
source 2-wire resistance
thermometer
(RTD)
Potentiometer Thermo-
couple (TC)
Safe state 1Threshold Threshold Threshold Threshold Threshold Threshold
Safety loop
fault detection
3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can
be detected
< 3.6 mA and
> 21 mA can
be detected
< 3.6 mA and
> 21 mA can
be detected
< 3.6 mA and
> 21 mA can
be detected
< 3.6 mA and
> 21 mA can
be detected
< 3.6 mA and
> 21 mA can
be detected
sd + su 0 FIT 0 FIT 0 FIT 0 FIT 0 FIT 0 FIT
dd 43 FIT 23.1 FIT 27 FIT 16 FIT 12.1 FIT 8.1 FIT
du 16 FIT 12 FIT 8.1 FIT 0.02 FIT 22.9 FIT 8 FIT
no effect 143 FIT 101 FIT 101 FIT 41.1 FIT 101 FIT 41.1 FIT
not part 0 FIT 66 FIT 66.1 FIT 145 FIT 66.1 FIT 145 FIT
total (safety
function)
59 FIT 35.1 FIT 35.1 FIT 16.02 FIT 34 FIT 16.1 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
564 years (all components of the device)
PFH 1.79 x 10-8 1/h 1.79 x 10-8 1/h 1.79 x 10-8 1/h 1.79 x 10-8 1/h 1.79 x 10-8 1/h 1.79 x 10-8 1/h
PFDavg for
T1 = 1 year 7.84 x 10-5 7.84 x 10-5 7.84 x 10-5 7.84 x 10-5 7.84 x 10-5 7.84 x 10-5
Table 3.5

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
2021-09
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P-LB-1.A.*, P-LB-2.A.* (1oo1 structure)
Parameters Characteristics
Assessment type
and documentation FMEDA report
Device type A
Mode of operation Low demand mode or high demand mode
Safety function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 1AI AO DI DO
Safe state 1Iin < 3.6 mA
Signal line
interrupted
Iout < 3.6 mA
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Safety loop fault
detection 3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can be
detected
No fault detection
since < 3.6 mA is
safe state of the
safety loop
SC and LB detection
of the safety loop No fault detection
sd + su 0 FIT 16.1 FIT 8.1 FIT 16.1 FIT
dd 16.1 FIT 0 FIT 8.0 FIT 0 FIT
du 0 FIT 0 FIT 0 FIT 0 FIT
no effect 41.1 FIT 41.1 FIT 41.1 FIT 41.1 FIT
not part 0 FIT 0 FIT 0 FIT 0 FIT
total (safety function) 16.1 FIT 16.1 FIT 16.1 FIT 16.1 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
2002 years (1-channel device), 1001 years (2-channel device)
PFH 0 1/h 0 1/h 0 1/h 0 1/h
PFDavg for
T1 = 1 year 0 0 0 0
Table 3.6

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
P-LB-1.B.*, P-LB-2.B.*, P-LB-1.C.*, P-LB-2.C.*, P-LB-2.D.*, P-LB-1.E.* (1oo1 structure)
The characteristic safety values like PFD, PFH, SFF, HFT and T1 are taken
from the FMEDA report. Observe that PFD and T1 are related to each other.
The function of the devices has to be checked within the proof test interval (T1).
Parameters Characteristics
Assessment type
and documentation FMEDA report
Device type A
Mode of operation Low demand mode or high demand mode
Safety function 1
1The safe state of the surge protection barrier depend on the application.
Pass through the signal
HFT 0
SIL 2
2The maximum safety integrity level of the safety loop in which the device might be used depends on the characteristics
of the whole saftey loop and the connected field devices in the application.
2 or 3
Signal type 1AI AO DI DO
Safe state 1Iin < 3.6 mA
Signal line
interrupted
Iout < 3.6 mA
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Iout = 0 mA
Uout = 0 V
Signal line
interrupted
Safety loop fault
detection 3
3This fault detection has to be provided by the safety loop architecture
(e. g. NAMUR signal – lead breakage and short circuit detection, current loop > 20 mA).
< 3.6 mA and
> 21 mA can be
detected
No fault detection
since < 3.6 mA is
safe state of the
safety loop
SC and LB detection
of the safety loop No fault detection
sd + su 0 FIT 16.1 FIT 8.1 FIT 16.1 FIT
dd 16.1 FIT 0 FIT 8.0 FIT 0 FIT
du 5.95 FIT 5.95 FIT 5.95 FIT 5.95 FIT
no effect 42.1 FIT 42.1 FIT 42.1 FIT 42.1 FIT
not part 52 FIT 52 FIT 52 FIT 52 FIT
total (safety function) 22.05 FIT 22.05 FIT 22.05 FIT 22.05 FIT
MTBF 4
4acc. to SN29500. This characteristic includes failures which are not part of the safety function/MTTR = 8 h.
984 years (1-channel device), 492 years (2-channel device)
PFH 0.59 x 10-8 1/h 0.59 x 10-8 1/h 0.59 x 10-8 1/h 0.59 x 10-8 1/h
PFDavg for
T1 = 1 year 2.60 x 10-5 2.60 x 10-5 2.60 x 10-5 2.60 x 10-5
Table 3.7

Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Planning
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3.5 Useful Lifetime
Although a constant failure rate is assumed by the probabilistic estimation this only applies
provided that the useful lifetime of components is not exceeded. Beyond this useful lifetime,
the result of the probabilistic estimation is meaningless as the probability of failure significantly
increases with time. The useful lifetime is highly dependent on the component itself
and its operating conditions – temperature in particular. For example, electrolytic capacitors
can be very sensitive to the operating temperature.
This assumption of a constant failure rate is based on the bathtub curve,
which shows the typical behavior for electronic components.
Therefore it is obvious that failure calculation is only valid for components that have
this constant domain and that the validity of the calculation is limited to the useful lifetime
of each component.
It is assumed that early failures are detected to a huge percentage during the installation
and therefore the assumption of a constant failure rate during the useful lifetime is valid.
However, according to IEC/EN 61508-2, a useful lifetime, based on general experience,
should be assumed. Experience has shown that the useful lifetime often lies within a range
period of about 8 to 12 years.
As noted in DIN EN 61508-2:2011 note N3, appropriate measures taken by the manufacturer
and plant operator can extend the useful lifetime.
Our experience has shown that the useful lifetime of a Pepperl+Fuchs product can be higher
if the ambient conditions support a long life time, for example if the ambient temperature
is significantly below 60 °C.
Please note that the useful lifetime refers to the (constant) failure rate of the device.
The effective life time can be higher.
The estimated useful lifetime is greater than the warranty period prescribed by law
or the manufacturer's guarantee period. However, this does not result in an extension
of the warranty or guarantee services. Failure to reach the estimated useful lifetime is not
a material defect.

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Functional Safety K-LB-*.*, F*-LB-I, P-LB-*.*.*
Mounting and Installation
4 Mounting and Installation
Mounting and Installing the Device
1. Observe the safety instructions in the instruction manual.
2. Observe the information in the manual.
3. Observe the requirements for the safety loop.
4. Connect the device only to devices that are suitable for this safety application.
5. Check the safety function to ensure the expected output behavior.
4.1 Configuration
A configuration of the device is not necessary and not possible.