Pepperl+Fuchs KFD2-VR4-Ex1.26 User manual

ISO9001
2
Functional Safety
Voltage Repeater
KFD2-VR4-Ex1.26
PROCESS AUTOMATION
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"
Functional Safety KFD2-VR4-Ex1.26

Functional Safety KFD2-VR4-Ex1.26
Content
2018-03
3
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.1 Content of this Document. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.2 Safety Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.3 Symbols Used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2 Product Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1 Function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.2 Interfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Standards and Directives for Functional Safety . . . . . . . . . . . . . . . . . . 7
3 Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1 System Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.2 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.3 Safety Function and Safe State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.4 Characteristic Safety Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.5 Useful Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4 Mounting and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5.1 Proof Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
6 Maintenance and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
7 List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

2018-03
4
Functional Safety KFD2-VR4-Ex1.26
Introduction
1Introduction
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.

Functional Safety KFD2-VR4-Ex1.26
Introduction
2018-03
5
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.

2018-03
6
Functional Safety KFD2-VR4-Ex1.26
Introduction
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.

Functional Safety KFD2-VR4-Ex1.26
Product Description
2018-03
7
2 Product Description
2.1 Function
This isolated barrier is used for intrinsic safety applications.
It provides a floating output to power a vibration sensor (e. g. Bently Nevada) or an
acceleration sensor in a hazardous area and transfers the voltage signal from that sensor
to the non-hazardous area.
The device is designed to provide the power supply to the vibration sensors. Depending
on connection the barrier provides 3.6 mA, 5.3 mA, or 8.9 mA supply current for
2-wire sensors, or 18 V at 20 mA for 3-wire sensors.
2.2 Interfaces
The device has the following interfaces.
• Safety relevant interfaces: input, output
• Non-safety relevant interfaces: power supply
2.3 Marking
2.4 Standards and Directives for Functional Safety
Device-specific standards and directives
System-specific standards and directives
Note!
For corresponding connections see datasheet.
Pepperl+Fuchs GmbH
Lilienthalstraße 200, 68307 Mannheim, Germany
Internet: www.pepperl-fuchs.com
KFD2-VR4-Ex1.26 Up to SIL 2
Functional safety IEC/EN 61508, part 1 –2, edition 2000:
Functional safety of electrical/electronic/programmable
electronic safety-related systems (manufacturer)
Functional safety IEC/EN 61511, part 1 –3, edition 2003:
Functional safety –Safety instrumented systems for the
process industry sector (user)

2018-03
8
Functional Safety KFD2-VR4-Ex1.26
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:
•thePFD
avg 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:
•thePFHvalue(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)
3.1.3 Safe Failure Fraction
The safe failure fraction describes the ratio of all safe failures and dangerous detected failures
to the total failure rate.
SFF = (s+ dd) / (s+ dd + du)
A safe failure fraction as defined in IEC/EN 61508 is only relevant for elements or (sub)systems
in a complete safety loop. The device under consideration is always part of a safety loop but
is not regarded as a complete element or subsystem.
For calculating the SIL of a safety loop it is necessary to evaluate the safe failure fraction
of elements, subsystems and the complete system, but not of a single device.
Nevertheless the SFF of the device is given in this document for reference.

Functional Safety KFD2-VR4-Ex1.26
Planning
2018-03
9
3.2 Assumptions
The following assumptions have been made during the FMEDA:
• The device will be used under average industrial ambient conditions comparable to
the classification "stationary mounted" according to MIL-HDBK-217F.
Alternatively, 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 may be assumed. 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.
• The device shall claim less than 15 % of the total failure budget for a SIL 2 safety loop.
• For a SIL 2 application operating in low demand mode the total PFDavg value of the
SIF (Safety Instrumented Function) should be smaller than 1 x 10-2, hence the maximum
allowable PFDavg value would then be 1.5 x 10-3.
• For a SIL 2 application operating in high demand mode the total PFH value of the
SIF should be smaller than 1 x 10-6 per hour, hence the maximum allowable PFH value
would then be 1.5 x 10-7 per hour.
• Since the safety loop has a hardware fault tolerance of 0and it is a type Adevice, the
SFF must be > 60 % according to table 2 of IEC/EN 61508-2 for a SIL 2 (sub) system.
• Failure rate based on the Siemens standard SN29500.
• Any safe failures that occur (e. g. output in safe state) will be corrected within 8 hours
(e. g. remove sensor fault).
• While the device is being repaired, measures must be taken to maintain the safety function
(e. g. substitution by a replacement device).
• Propagation of failures is not relevant.
• There is no signalization of dangerous failures available at the output of the device.
Therefore any fault detection by external safety devices is not assumed.

2018-03
10
Functional Safety KFD2-VR4-Ex1.26
Planning
3.3 Safety Function and Safe State
Safety Function
The safety function of the device is fulfilled, as long as the output repeats the input voltage
(0 V ... -20 V) with a tolerance of ±2%.
Safe State
The safe state is defined, as the output being de-energized.
Reaction Time
The time that is needed to transfer a signal from the input of the device to the output according
to the safety function.
Note!
See corresponding datasheets for further information.

Functional Safety KFD2-VR4-Ex1.26
Planning
2018-03
11
3.4 Characteristic Safety Values
The characteristic safety values like PFD, PFH, SFF, HFT and T1are taken from the
FMEDA report. Observe that PFD and T1are related to each other.
The function of the devices has to be checked within the proof test interval (T1).
Parameters Characteristic values
Assessment type FMEDA report
Device type A (only hardware)
Mode of protection Low demand mode or high demand mode
HFT 0
SIL (hardware) 2
sd + su1
1Failures in components that are part of the safety function but do not influence the safety function are regarded as safe undetected.
338 FIT
dd 0 FIT
du 103 FIT
total (safety function) 477 FIT
not part 35.1 FIT
SFF 76 %
PTC 100 %
MTBF 2
2acc. to SN29500. This value includes failures which are not part of the safety function/MTTR = 8 h.
239 years
PFH 1.03 x 10-7 1/h
PFDavg for T1= 1 year 4.52 x 10-4
PFDavg for T1= 3 years 9.03 x 10-3
PFDavg for T1= 5 years 2.26 x 10-3
Reaction time 3
3The time that is needed to transfer a signal from the input of the device to the output according to the safety function.
12.5 µs
Table 3.1

2018-03
12
Functional Safety KFD2-VR4-Ex1.26
Planning
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, the 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
periodofabout8to12years.
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.

Functional Safety KFD2-VR4-Ex1.26
Mounting and Installation
2018-03
13
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.

2018-03
14
Functional Safety KFD2-VR4-Ex1.26
Operation
5Operation
Operating the device
1. Observe the safety instructions in the instruction manual.
2. Observe the information in the manual.
3. Use the device only with devices that are suitable for this safety application.
4. Correct any occurring safe failures within 8 hours. Take measures to maintain the safety
function while the device is being repaired.
5.1 Proof Test
According to IEC/EN 61508-2 a recurring proof test shall be undertaken to reveal potential
dangerous failures that are not detected otherwise.
Check the function of the subsystem at periodic intervals depending on the applied
PFDavg in accordance with the characteristic safety values. See chapter 3.4.
It is possible that the device is used under other circumstances than specified within
the assumptions for the FMEDA assessment. The calculations for the safety loop can also
reveal that the device can claim a different amount of the PFD value (standard is 15 %).
Both effects can have an influence on the proof test interval.
The proof test detects dangerous undetected failures that can affect the safety function
of the plant.
It is under the responsibility of the plant operator to define the type of proof test and the proof
test interval. Do not exceed the proof test interval of a maximum of 3 years.
The following sections describe the steps of the proof test. The proof test reveals almost
all possible dangerous faults (diagnostic coverage > 90 %).
The ancillary equipment required:
• Digital multimeter with an accuracy better than 0.1 %
For the proof test of the intrinsic safety side of the devices, a special digital multimeter
for intrinsically safe circuits must be used.
Intrinsically safe circuits that were operated with non-intrinsically safe circuits may not
be used as intrinsically safe circuits afterwards.
• Power supply set at nominal voltage of 24 V DC.
• Apparatus suitable for generating the signals for test B.
•Loadof2.1kand 1.8 kfor the input, 10 kfor the output.
Danger!
Danger to life from missing safety function
If the safety loop is put out of service, the safety function is no longer guaranteed.
• Do not deactivate the device.
• Do not bypass the safety function.
• Do not repair, modify, or manipulate the device.

Functional Safety KFD2-VR4-Ex1.26
Operation
2018-03
15
Proof Test Procedure A
1. Prepare the test set-up, see next figure.
2. Connect an input load of 2.1 kto terminals 4+ and 5-.
3. Connect an output load of 10 kto terminals 7- and 8+.
4. Connect the power supply to terminals 11+ and 12- or via Power Rail.
5. Connect a voltage source to terminals 4 (common) and 2 (input).
6. Apply voltages of -5 V, -10 V. -20 V at the input.
7. Measure the output voltage.
The output voltage must be within ±200 mV.
8. Disconnect the ancillary equipment.
9. Set back the device to the original settings after the test.
10. Restore the safety loop.
Proof Test Procedure B
1. Prepare the test set-up, see next figure.
2. Connect an input load of 2.1 kto terminals 4+ and 5-.
3. Connect an output load of 10 kto terminals 7- and 8+.
4. Connect the power supply to terminals 11+ and 12- or via Power Rail.
5. Apply a voltage of -2 V DC + 1.414 Vrms sine wave at 20 kHz at the input.
6. Measure the amplitude of the sine wave at input and output.
The output voltage amplitude must be at least 0.891 times the input voltage amplitude
(i. e. the reduction in amplitude must not exceed 1 dB).
7. Disconnect the ancillary equipment.
8. Set back the device to the original settings after the test.
9. Restore the safety loop.
Input voltage Output voltage
-5 V -5 V ±200 mV
-10 V -10 V ±200 mV
-20 V -20 V ±200 mV
Table 5.1

2018-03
16
Functional Safety KFD2-VR4-Ex1.26
Operation
Figure 5.1 Set-up for proof tests A and B
Zone 0, 1, 2
Div. 1, 2
Zone 2
Div. 2
Multimeter
(V)
4+
6-
2-
3-
1-
5-
KFD2-VR4-Ex1.26
7-
8+
24 V DC
11+
12-
Power Rail
24V DC
Input
load
2.1 kΩ
Output
load
10 kΩ
Input
voltage
3.6 mA 5.3 mA

Functional Safety KFD2-VR4-Ex1.26
Operation
2018-03
17
Proof Test Procedure C
1. Prepare the test set-up, see figure below.
2. Connect an input load of 1.8 kto terminals 1- and 4+.
3. Measure the voltage load across the resistor and the current derived from it.
The current value must be between 4.9 mA and 5.7 mA.
4. Disconnect the ancillary equipment.
5. Set back the device to the original settings after the test.
6. Restore the safety loop.
Figure 5.2 Set-up for proof test C
Zone 0, 1, 2
Div. 1, 2
Zone 2
Div. 2
4+
6-
2-
3-
1-
5-
KFD2-VR4-Ex1.26
7-
8+
Multimeter
(V)
24 V DC
11+
12-
Power Rail
24V DC
Input load
1.8 kΩ
3.6 mA 5.3 mA

2018-03
18
Functional Safety KFD2-VR4-Ex1.26
Operation
Proof Test Procedure D
1. Prepare the test set-up, see figure below.
2. Connect an input load of 1.8 kto terminals 3- and 4+.
3. Measure the voltage load across the resistor and the current derived from it.
The current value must be between 2.9 mA and 4.3 mA.
4. Disconnect the ancillary equipment.
5. Set back the device to the original settings after the test.
6. Restore the safety loop.
Figure 5.3 Set-up for proof test D
Zone 0, 1, 2
Div. 1, 2
Zone 2
Div. 2
4+
6-
2-
3-
1-
5-
KFD2-VR4-Ex1.26
7-
8+
24 V DC
11+
12-
Power Rail
24V DC
Multimeter
(V)
Input load
1.8 kΩ
3.6 mA 5.3 mA

Functional Safety KFD2-VR4-Ex1.26
Maintenance and Repair
2018-03
19
6 Maintenance and Repair
Maintaining, Repairing or Replacing the Device
In case of maintenance, repair or replacement of the device, proceed as follows:
1. Implement appropriate maintenance procedures for regular maintenance of the safety loop.
2. Ensure the proper function of the safety loop, while the device is maintained, repaired
or replaced.
If the safety loop does not work without the device, shut down the application.
Do not restart the application without taking proper precautions.
Secure the application against accidental restart.
3. Do not repair a defective device. A defective device must only be repaired by the
manufacturer.
4. Replace a defective device only by a device of the same type.
Danger!
Danger to life from missing safety function
If the safety loop is put out of service, the safety function is no longer guaranteed.
• Do not deactivate the device.
• Do not bypass the safety function.
• Do not repair, modify, or manipulate the device.

2018-03
20
Functional Safety KFD2-VR4-Ex1.26
List of Abbreviations
7 List of Abbreviations
ESD Emergency Shutdown
FIT Failure In Time in 10-9 1/h
FMEDA Failure Mode, Effects, and Diagnostics Analysis
sProbability of safe failure
dd Probability of dangerous detected failure
du Probability of dangerous undetected failure
no effect Probability of failures of components in the safety loop that have no
effect on the safety function. The no effect failure is not used for
calculation of SFF.
not part Probability of failure of components that are not in the safety loop
total (safety function) Probability of failure of components that are in the safety loop
HFT Hardware Fault Tolerance
MTBF Mean Time Between Failures
MTTR Mean Time To Restoration
PCS Process Control System
PFDavg Average Probability of dangerous Failure on Demand
PFH Average frequency of dangerous failure
PLC Programmable Logic Controller
PTC Proof Test Coverage
SFF Safe Failure Fraction
SIF Safety Instrumented Function
SIL Safety Integrity Level
SIL (SC) Safety Integrity Level (Systematic Capability)
SIS Safety Instrumented System
T1Proof Test Interval