Pepperl+Fuchs KFD2-UT2 Series User manual

ISO9001
2
Functional Safety
Temperature Converter
KFD2-UT2-(Ex)*(-1)
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-UT2-(Ex)*(-1)

Functional Safety KFD2-UT2-(Ex)*(-1)
Content
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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 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.3 Marking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.4 Standards and Directives for Functional Safety . . . . . . . . . . . . . . . . . . 8
3 Planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 System Structure. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Assumptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.3 Safety Function and Safe State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
3.4 Characteristic Safety Values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
3.5 Useful Lifetime . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4 Mounting and Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
4.1 Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5 Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1 Proof Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.2 Proof Test Procedure for KFD2-UT2-(Ex)*(-1) . . . . . . . . . . . . . . . . . . 16
6 Maintenance and Repair . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
7 List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

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Functional Safety KFD2-UT2-(Ex)*(-1)
Introduction
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.

Functional Safety KFD2-UT2-(Ex)*(-1)
Introduction
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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.

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Functional Safety KFD2-UT2-(Ex)*(-1)
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-UT2-(Ex)*(-1)
Product Description
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2 Product Description
2.1 Function
KFD2-UT2-*(-1)
This signal conditioner provides the galvanic isolation between field circuits and
control circuits.
The device converts the signal of a resistance thermometer, thermocouple, or potentiometer
to a proportional output current.
The device can also be configured as a signal splitter.
The removable terminal block K-CJC-** is available as an accessory for internal cold junction
compensation of thermocouples.
A fault is signalized by LEDs and a separate collective error message output.
The device is easily configured by the use of the PACTware configuration software.
The device is mounted on a 35 mm DIN mounting rail according to EN 60715.
KFD2-UT2-*-1
The device converts the signal of a resistance thermometer, thermocouple, or potentiometer
to a proportional output voltage.
KFD2-UT2-Ex*(-1)
This isolated barrier is used for intrinsic safety applications.
The device converts the signal of a resistance thermometer, thermocouple, or potentiometer
to a proportional output current.
The device can also be configured as a signal splitter.
The removable terminal block K-CJC-** is available as an accessory for internal cold junction
compensation of thermocouples.
A fault is signalized by LEDs and a separate collective error message output.
The device is easily configured by the use of the PACTware configuration software.
The device is mounted on a 35 mm DIN mounting rail according to EN 60715.
KFD2-UT2-Ex*-1
The device converts the signal of a resistance thermometer, thermocouple, or potentiometer
to a proportional output voltage.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Product Description
2.2 Interfaces
The device has the following interfaces.
• Safety relevant interfaces:
• Input I, input II (only 2-channel version)
• Output I, output II (only 2-channel version)
• Non-safety relevant interfaces: programming socket, collective error message output
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 Group
Lilienthalstraße 200, 68307 Mannheim, Germany
Internet: www.pepperl-fuchs.com
KFD2-UT2-1, KFD2-UT2-1-1, KFD2-UT2-2, KFD2-UT2-2-1 Up to SIL 2
KFD2-UT2-Ex1, KFD2-UT2-Ex1-1,KFD2-UT2-Ex2, KFD2-UT2-Ex2-1
Functional safety IEC/EN 61508, part 2 and 3, edition 2010:
Functional safety of electrical/electronic/programmable
electronic safety-related systems (manufacturer)
Functional safety IEC 61511-1:2016+COR1:2016+A1:2017
EN 61511-1:2017+A1:2017
Functional safety –Safety instrumented systems
for the process industry sector (user)

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Planning
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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)
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.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Planning
3.2 Assumptions
The following assumptions have been made during the FMEDA:
• Failure rate based on the Siemens standard SN 29500.
• Failures during configuration are not considered.
• The collective error message output is not considered in the FMEDA and
in the calculations.
• Propagation of failures is not relevant.
• External power supply failure rates are not included.
• The collective error message output is not safety relevant.
• The indication of a dangerous failure (via fault bus) is detected within 1 hour
by the programmable logic controller (PLC).
• Only one input and one output are part of the safety function (only for 2-channel version).
• 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 application program in the programmable logic controller (PLC) is configured to detect
underrange and overrange failures. These failures have been classified as dangerous
detected failures.
SIL 2 Application
• To build a SIL safety loop for the defined SIL, it is assumed as an example that this device
uses 10 % of the available budget for PFDavg/PFH.
• For a SIL 2 application operating in low demand mode the total PFDavg value of
the SIF (Safety Instrumented Function) should be smaller than 10-2, hence the maximum
allowable PFDavg value would then be 10-3.
• According to IEC/EN 61511-1 section 11.4.5, a HFT = 0 can be considered sufficient for
SIL 2 applications in low demand mode of operation. The evaluation is based on failure
rates as described in section 11.9.

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Planning
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3.3 Safety Function and Safe State
Safety Function
The safety function of the device is fulfilled, as long as the output repeats the linearized
input signal with a tolerance of 2 %.
Safe State
The safe state is present when the output signal is < 4 mA or > 20 mA.
Reaction Time
• for temperature input: < 1.5 s
• for potentiometer input: < 3 s
Note
See corresponding datasheets for further information.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Planning
3.4 Characteristic Safety Values
The following tables contains no SFF data, since this value has to be calculated
with consideration of the connected field device.
KFD2-UT2-(Ex)*
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 Characteristic values
Assessment type FMEDA report with proven-in-use assessment 1
Device type B
Mode of operation Low demand mode
Safety function Transfer of analog value
HFT 0 (acc. to IEC/EN 61511)
SIL 2
SC 2
s0 FIT
dd2 333 FIT
du3 79.2 FIT
no effect4 295 FIT
total (safety function) 706 FIT
no part 33.4 FIT
SFF 81 %
MTBF 5 154 years
PFDavg for T1 = 1 year 6 8.33 x 10-4
PFDavg for Tproof = 2 years 61.14 x 10-3
PFDavg for Tproof = 5 years 62.08 x 10-3
PTC 90 %
Reaction time 7 • for temperature input: < 1.5 s
• for potentiometer input: < 3 s
Table 3.1
1For the proven-in-use demonstration, sales figures, customer returns and questionnaires filled out by customers were used
which show that no unknown systematic faults are expected. The device is based on a former device that was evaluated
for a proven-in-use statement by exida.com GmbH.
2"Fail high" and "Fail low" failures are considered as dangerous detected failures dd.
3"Annunciation failures" that only influence the diagnostic function were marginal and added to the du.
4"No effect failures" are not influencing the safety function and are therefore added to the s.
5acc. to SN29500. This value includes failures which are not part of the safety function/MTTR = 8 h.
6Since the current PTC value is < 100 % and therefore the probability of failure will increase, calculate the PFD value
according to the following formula:
PFDavg = (du / 2) x (PTC x T1 + (1 – PTC) x Tservice)
A service time Tservice of 10 years was assumed for the calculation of PFDavg.
7Step response time

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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, 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
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 KFD2-UT2-(Ex)*(-1)
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. Protect the device against manipulation. Mount the device in a lockable switch cabinet,
for example.
5. Connect the device only to devices that are suitable for this safety application.
6. Check the safety function to ensure the expected output behavior.
4.1 Configuration
Configuring the Device via PACTware Operating Software
The device can also be configured via the PACTware operating software.
The interface for connecting a personal computer for configuring is on the front of the device.
1. Open the cover.
2. Connect a personal computer via the K-ADP-USB adapter to the device.
3. Configure the device for the required safety function via the PACTware operating software,
see chapter 4.1.1.
4. Protect the device configuration by a password against changing.
5. Leave the parameterization mode to prevent unintentional adjustments.
6. Disconnect the personal computer from the device.
7. Close the cover.
8. Check the device configuration to ensure the expected output behavior.
9. Document any changes to the device configuration.
4.1.1 Configuration for Use in Safety Function
Configuring the Device for Use in Safety Function
1. Configure the device for the required safety function via the operating software.
2. Disable the simulation function.
3. Enable the short circuit (SC) detection and lead breakage (LB) detection.
4. Disable the fault indication function > Hold.
5. Set the characteristic of the current output to the 4 mA to 20 mA NE 43 mode.
6. Protect the device configuration by a password against changing.
Note
For more information see the manual.
Note
For more information see the manual.

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Operation
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5 Operation
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
This section describes a possible proof test procedure. The user is not obliged to use
this proposal. The user may consider different concepts with an individual determination
of the respective effectiveness, e. g. concepts according to NA106:2018.
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 under the responsibility of the plant operator to define the type of proof test
and the interval time period.
The following sections describe the steps of the proof test. The proof test reveals almost
all possible dangerous faults (diagnostic coverage > 90 %).
Check the settings after the configuration by suitable tests.
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.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Operation
5.2 Proof Test Procedure for KFD2-UT2-(Ex)*(-1)
Perform the proof test with the same configuration that you use in the application.
Substitute the sensor with a sensor simulator or a calibrator.
Check the safety function at the input, which must be configured to set the output values
to 4 mA, 12 mA, 20 mA.
Equipment required:
• Digital multimeter with an accuracy of 0.1 %
Use for the proof test of the intrinsic safety side of the device a special digital multimeter
for intrinsically safe circuits.
If intrinsically safe circuits are operated with non-intrinsically safe circuits,
they must no longer be used as intrinsically safe circuits.
• TC simulator, RTD simulator, voltage source or resistor

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Operation
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5.2.1 Thermocouple Input (TC)
Figure 5.1 Proof test set-up for KFD2-UT2-(Ex)*(-1) with thermocouple input (TC)
Usage in Zone 0, 1, 2/Div. 1, 2 only for KFD2-UT2-Ex1(-1) and KFD2-UT2-Ex2(-1)
1-channel versions KFD2-UT2-1(-1) and KFD2-UT2-Ex1(-1) have only one channel.
Proof Test Procedure
Additional equipment: 110  fixed resistor (accuracy of 0.1 %)
1. Connect the TC simulator to the terminals 1+ and 2- (channel I) and 4+ and 5- (channel II).
2. Connect the digital multimeter to the terminals 7 and 8 (channel I)
and 10 and 11 (channel II).
3. Set the compensation/reference temperature on the TC simulator to 26 °C.
4. Connect the fixed resistor to terminals 2 and 3 (channel I) and 5 and 6 (channel II).
5. Set the TC simulator sequentially to the temperature values
representing 4 mA, 12 mA, 20 mA at the output.
6. Measure the output current.
The proof test is passed if the output values are within 2 % of the output span. 1
This means:
– for the 4 mA application: 3.7 mA to 4.3 mA
– for the 12 mA application: 11.7 mA to 12.3 mA
– for the 20 mA application: 19.7 mA to 20.3 mA
7. Remove the TC simulator. Check if a lead breakage is detected.
The red LED is flashing. The output behavior in the event of a fault depends
on the device configuration.
KFD2-UT2-Ex2
Zone 0, 1, 2
Div. 1, 2
2
3
1
5
6
4
7
9-
8+
10
12-
11+
110Ω
TC
Sim.
110Ω
TC
Sim.
Fault
I supply
Zone 2
Div. 2
Multimeter
(mA)
Multimeter
(mA)
I
II
Supply +
Supply -
24 V DC
Power
supply
Supply
Bus
1Additionally the loop diagnosis shall be tested to prove that the fault signaling via the current output is working
correctly. The output current in the event of a failure depends on the device configuration. Please record
this configuration and the resulting expected fault signaling current in the test report. Example: if downscale
is configured, 2.0 mA ±1 % must be measured in the event of a failure. The red LED must be flashing.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Operation
8. Remove the fixed resistor. Check if a lead breakage of the CJCs are detected.
The red LED is flashing. The output behavior in the event of a fault depends
on the device configuration.
9. Apply short circuit between terminals 2 and 3 (channel I) and between
terminals 5 and 6 (channel II). Check if a short circuit of the cold junction compensation
is detected.
The red LED is flashing. The output behavior in the event of a fault depends
on the device configuration.
10. Set the device back to the original settings after the test.
Proof Test for external Cold Junction Compensation
You can also use this proof test if you are using an external cold junction compensation.
In this case set the preset compensation/reference temperature on the TC simulator,
see step 3.

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Operation
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5.2.2 Resistance Thermometer Input (RTD)
Figure 5.2 Proof test set-up for KFD2-UT2-(Ex)*(-1) with resistance thermometer input (RTD)
Usage in Zone 0, 1, 2/Div. 1, 2 only for KFD2-UT2-Ex1(-1) and KFD2-UT2-Ex2(-1)
1-channel versions KFD2-UT2-1(-1) and KFD2-UT2-Ex1(-1) have only one channel.
Proof Test Procedure
1. Connect a RTD simulator, depending on the application.
• for 4-wire connection: terminals 1, 2, 3, 4
• for 3-wire connection: terminals 1, 2, 3 (channel I) and 4, 5, 6 (channel II)
• for 2-wire connection: terminals 2, 3 (channel I) and 5, 6 (channel II)
2. Connect the digital multimeter terminals 7 and 8 (channel I) and 10 and 11 (channel II).
3. Set the RTD simulator sequentially to the temperature values
representing 4 mA, 12 mA, 20 mA at the output.
4. Measure the output current.
The proof test is passed if the output values are within 2 % of the output span. 1
This means:
– for the 4 mA application: 3.7 mA to 4.3 mA
– for the 12 mA application: 11.7 mA to 12.3 mA
– for the 20 mA application: 19.7 mA to 20.3 mA
5. Apply short circuit between terminals 2 and 3 (channel I) and between
terminals 5 and 6 (channel II). Do not remove the RTD simulator. Check if a short circuit
of the cold junction compensation is detected.
The red LED is flashing. The output behavior in the event of a fault depends
on the device configuration.
KFD2-UT2-Ex2
Zone 0, 1, 2
Div. 1, 2 Zone 2
Div. 2
TT
T
2
3
1
5
6
4
7
9-
8+
10
12-
11+
Fault
I supply
Multimeter
(mA)
Multimeter
(mA)
I
II
Supply +
Supply -
24 V DC
Power
supply
Supply
Bus
1Additionally the loop diagnosis shall be tested to prove that the fault signaling via the current output is working
correctly. The output current in the event of a failure depends on the device configuration. Please record
this configuration and the resulting expected fault signaling current in the test report. Example: if downscale
is configured, 2.0 mA ±1 % must be measured in the event of a failure. The red LED must be flashing.

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Functional Safety KFD2-UT2-(Ex)*(-1)
Operation
6. Remove the RTD simulator. Check if a lead breakage is detected.
The red LED is flashing. The output behavior in the event of a fault depends
on the device configuration.
7. Set the device back to the original settings after the test.