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SAFETY MANUAL SIL
RELAY MODULE
KFD0-RSH-1.4S.PS2
PROCESS AUTOMATION
ISO9001
3
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
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"
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Contents
1 Introduction......................................................................... 4
1.1 General Information.......................................................................................4
1.2 Intended Use ................................................................................................4
1.3 Manufacturer Information..............................................................................5
1.4 Relevant Standards and Directives ...............................................................5
2 Planning .............................................................................. 6
2.1 System Structure...........................................................................................6
2.1.1 Low Demand Mode .................................................................................6
2.1.2 High Demand Mode .................................................................................6
2.2 Assumptions ................................................................................................7
2.3 Safety Function and Safe State .....................................................................8
2.4 Characteristic Safety Values .........................................................................9
3 Safety Recommendation.................................................. 10
3.1 Interfaces....................................................................................................10
3.2 Configuration ..............................................................................................10
3.3 Useful Life Time ..........................................................................................10
3.4 Installation and Commissioning ..................................................................11
4 Proof Test .......................................................................... 12
4.1 Proof Test Procedure ..................................................................................12
5 Abbreviations.................................................................... 16
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Introduction
1Introduction
1.1 General Information
This manual contains information for application of the device in functional safety
related loops.
The corresponding data sheets, the operating instructions, the system
description, the Declaration of Conformity, the EC-Type-Examination Certificate,
the Functional Safety Assessment and applicable Certificates (see data sheet)
are integral parts of this document.
The documents mentioned are available from www.pepperl-fuchs.com or by
contacting your local Pepperl+Fuchs representative.
Mounting, commissioning, operation, maintenance and dismounting of any
devices may only be carried out by trained, qualified personnel. The instruction
manual must be read and understood.
When it is not possible to correct faults, the devices must be taken out of service
and action taken to protect against accidental use. Devices should only be
repaired directly by the manufacturer. De-activating or bypassing safety functions
or failure to follow the advice given in this manual (causing disturbances or
impairment of safety functions) may cause damage to property, environment or
persons for which Pepperl+Fuchs GmbH will not be liable.
The devices are developed, manufactured and tested according to the relevant
safety standards. They must only be used for the applications described in the
instructions and with specified environmental conditions, and only in connection
with approved external devices.
1.2 Intended Use
This signal conditioner is a loop powered safety relay module with a logic input
and two different relay outputs:
It can be used as an interface in output loops for fire and gas systems classified as
SIL3. The safe state in this application is energized to safe (ETS). Output I with
two relays in parallel must be used, no fuse available.
It can also be used as an interface in output loops for ESD (Emergency Shut
Down) systems classified as SIL3. The safe state in this application is
de-energized to safe (DTS). Output II with two relays in series must be used. An
additional fuse in series to the relay contacts is available (see chapter 3).
With both outputs in combination a non safety application for dual pole switching
(DPS) is possible.
Additionally a test input for proof tests is available. The proof test checks if each
single relay is working correctly.
The device is usually mounted on a DIN rail in cabinets with access for qualified
personnel only.
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Introduction
1.3 Manufacturer Information
Pepperl+Fuchs GmbH
Lilienthalstrasse 200
68307 Mannheim/Germany
KFD0-RSH-1.4S.PS2
Up to SIL3 (for DTS), up to SIL3 (for ETS)
1.4 Relevant Standards and Directives
Device specific standards and directives
■ Functional safety IEC 61508 part 1 – 7, edition 2000:
Standard of functional safety of electrical/electronic/programmable electronic
safety-related systems (product manufacturer)
■ Electromagnetic compatibility:
- EN 61326-1:2006
- NE 21:2006
System specific standards and directives
■ Functional safety IEC 61511 part 1 – 3, edition 2003:
Standard of functional safety: safety instrumented systems for the process
industry sector (user)
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Planning
2 Planning
2.1 System Structure
2.1.1 Low Demand Mode
If there are two 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 PFD
(proof test interval that has a direct impact on the PFD
■ the SFF value (Safe Failure Fraction)
■ the HFT architecture (Hardware Fault Tolerance architecture)
2.1.2 High Demand Mode
If there is only one loop, which combines the standard operation and safety
related operation, then usually the demand rate for this loop is assumed to be
higher than once per year.
The relevant safety parameters to be verified are:
■ PFH (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 architecture)
value (average Probability of Failure on Demand) and T
avg
avg
)
proof
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Planning
2.2 Assumptions
The following assumptions have been made during the FMEDA analysis:
■ Failure rates are constant, wear out mechanisms are not included.
■ The stress levels are average for an industrial environment and can be
compared to the Ground Fixed Classification of MIL-HNBK-217F.
Alternatively, the assumed environment is similar to:
• IEC 60654-1 Class C (sheltered location) with temperature limits within
the manufacturer's rating and an average temperature over a long period
of time of 40 ºC. Humidity levels are assumed within manufacturer's
rating. For a higher average temperature of 60 ºC, the failure rates should
be multiplied with an experience based factor of 2.5. A similar multiplier
should be used if frequent temperature fluctuation must be assumed.
■ Failure rate based on the Siemens SN29500 data base.
■ It was assumed that the appearance of a safe error (e. g. output in safe state)
would be repaired within 8 hours.
■ During the absence of the device for repairing, measures have to be taken to
ensure the safety function (for example: substitution by an equivalent device).
■ For high currents and high ambient temperature the de-rating given in the data
sheet needs to be considered.
■ The input of the device must be connected to a safety PLC which has
minimum the SIL needed in the loop.
■ The device shall claim less than 10 % of the total failure budget for a
SIL3 safety loop.
■ For a SIL3 application operating in Low Demand Mode the total PFD
of the SIF (Safety Instrumented Function) should be smaller than 10
the maximum allowable PFD
■ For a SIL3 application operating in High Demand Mode of operation the total
PFH value of the SIF should be smaller than 10
maximum allowable PFH value would then be 10
■ Since the circuit has a Hardware Fault Tolerance of 0 and it is a type A
component, the SFF must be > 90 % according to table 2 of IEC 61508-2 for
SIL3 (sub)system.
avg
value would then be 10-4.
-7
per hour, hence the
-8
per hour.
value
avg
-3
, hence
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Planning
2.3 Safety Function and Safe State
DTS
Safety Function
The safety function of the device is defined: Whenever the input of the device is
de-energized, the DTS output is not conducting.
Safe State
For the DTS safety function the safe state is defined as the DTS output being open
(not conducting).
Reaction Time
The reaction time is < 20 ms.
ETS
Safety Function
The safety function of the device is defined: Whenever the input of the device is
energized, the ETS output is conducting.
Safe State
For the ETS safety function the safe state is defined as the ETS output being
closed (conducting).
Reaction Time
The reaction time is < 20 ms.
DPS
The dual pole switching application is no safety application.
Ge n e r a l
For all applications the maximum switching frequency is limited to 10 Hz.
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Planning
2.4 Characteristic Safety Values
Parameters acc. to IEC 61508 Var iab les
Assessment type and
documentation
Pepperl+Fuchs FMEDA report 1FS-0042EA-20A
Device type A
Demand mode Low Demand Mode or High Demand Mode
Safety function
2
HFT 0 0
SIL 3 3
λsd + λ
su
λ
dd
λ
du
λ
total (safety function)
SFF 95.2 % 98.7 %
3
MTBF
PFH 7.1 x 10-9 1/h 1.83 x 10-9 1/h
PFD
for T1 = 1 year 3.1 x 10
avg
T
max. 3 years 12 years
proof
Reaction time < 20 ms
1
Pepperl+Fuchs documentation number
2
The device can be used in two safety functions, ETS (energized to safe) and DTS (de-energized to safe).
3
acc. to SN29500. This value includes failures which are not part of the safety function/MTTR = 8 h.
4
For ETS in SIL2 applications no proof test has to be carried out, the calculated proof time is h igher than the
useful time (T
max. for ETS SIL2 is 32 years).
proof
The characteristic safety values like PFD/PFH, SFF, HFT and T
the SIL report/FMEDA report. Please note, PFD and T
other.
The function of the devices has to be checked within the proof test interval
).
(T
proof
Full a ssess ment
4
ETS
DTS
139.7 FIT 144.77 FIT
0 FIT 0 FIT
7.1 FIT 1.83 FIT
146.6 FIT 146.6 FIT
639 years 560 years
-5
8.01 x 10
proof
-6
are taken from
proof
are related to each
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Safety Recommendation
3 Safety Recommendation
3.1 Interfaces
The device has the following interfaces. For corresponding terminals see data
sheet.
■ Safety relevant interfaces: input, output I (ETS), output II (DTS)
■ To avoid contact welding in DTS application we recommend to use a serial
fuse in the load circuit. This can be the internal fuse F1 or any external fuse of
max. 5 A nominal value.
■ Test input interface may not be used during normal operation (only for proof
test)
3.2 Configuration
A configuration of the device is not necessary and not possible.
ETS, DTS and DPS can be selected by using the referring terminals. See data
sheet. The fuse in delivery status (2.5 A) can be changed to max 5 A. Please note
the temperature derating according to the data sheet.
3.3 Useful Life Time
Although a constant failure rate is assumed by the probabilistic estimation this
only applies provided that the useful life time of components is not exceeded.
Beyond this useful life time, the result of the probabilistic calculation is
meaningless as the probability of failure significantly increases with time. The
useful life time 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 working 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 life time of each component.
It is assumed that early failures are detected to a huge percentage during the
installation period and therefore the assumption of a constant failure rate during
the useful life time is valid.
However, according to IEC 61508-2, a useful life time, based on experience,
should be assumed. Experience has shown that the useful life time often lies
within a range period of about 8 ... 12 years.
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Safety Recommendation
Our experience has shown that the useful life time of a Pepperl+Fuchs product
can be higher
■ if there are no components with reduced life time in the safety path (like
electrolytic capacitors, relays, flash memory, opto coupler) which can produce
dangerous undetected failures and
■ if the ambient temperature is significantly below 60 °C.
Please note that the useful life time refers to the (constant) failure rate of the
device. The effective life time can be higher.
Maximum Switching Power of Output Contacts
The useful life time is limited by the maximum switching cycles under load
conditions. You can see the relationship between the maximum switching power
and the load conditions in the diagram below.
Resistive load
DC
30
100502010
115
0.6
0.3
Figure 3.1
I (A)
5
2
1
0.5
0.2
0.1
0
3.4 Installation and Commissioning
Installation has to consider all aspects regarding the SIL level of the loop. During
installation or replacement of the device the loop has to shut down. Devices have
to be replaced by the same type of devices.
Resistive load
AC
200
253
220
5
max. 10
switching cycles
max. 3 x 10
switching cycles
4
U (V)
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Proof Test
4 Proof Test
4.1 Proof Test Procedure
According to IEC 61508-2 a recurring proof test shall be undertaken to reveal
potential dangerous fails that are otherwise not detected by diagnostic test.
The functionality of the subsystem must be verified at periodic intervals
depending on the applied PFD
chapter 2.4.
It is under the responsibility of the operator to define the type of proof test and the
interval time period.
The ancillary equipment required:
■ A digital multimeter (without special accuracy) will be used as ohmmeter
(mid range recommended) to check the relay outputs. Closed contacts are
shown with 0 Ω (low impedance), open contacts are shown with OL
(overload/high impedance).
■ Power supply set at nominal voltage of 24 V DC
Procedure:
For the proof test five tests have to be done as shown in the following table and
pictures:
avg
in accordance with the data provided in see
Test No. Input or Test Input Output (mA)
1 V
2 V
3 V
4 V
5 V
= 24 V DC
test input
between terminals 10+, 11-
= 24 V DC
test input
between terminals 11-, 12+
= 24 V DC
test input
between terminals 10+, 11- and
between terminals 11-, 12+
= 0 V DC
test input
between terminals 10+, 11- and
between terminals 11-, 12+
= 24 V DC
input
between terminals 7+ and 8- and with changed
input polarity between terminals 7-, 8+
■ DTS output (terminals 5, 6): OL (overload)
■ ETS output (terminals 2, 3): shows 0 Ω
■ Red LED TST1 is flashing.
■ DTS output (terminals 5, 6): OL (overload)
■ ETS output (terminals 2, 3): shows 0 Ω
■ Red LED TST2 is flashing.
■ DTS output (terminals 5, 6): shows 0 Ω
■ ETS output (terminals 2, 3): shows 0 Ω
■ Both red LEDs are flashing.
■ DTS output (terminals 5, 6): OL (overload)
■ ETS output (terminals 2, 3): OL (overload)
■ Both red LEDs are off.
■ DTS output (terminals 5, 6): shows 0 Ω
■ ETS output (terminals 2, 3): shows 0 Ω
■ Yellow LED is on.
Table 4.1 Expected test results for a successful proof test
12
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
10
12+
11-
24 V
4
5
6
2
3
Multimeter
(Ω )
Multimeter
(Ω )
Proof Test
Multimeter
(Ω )
2
3
Multimeter
(Ω )
Figure 4.1 Proof test set-up for KFD0-RSH-1.4S.PS2, test 1
4
5
6
10+
11-
12
24 V
Figure 4.2 Proof test set-up for KFD0-RSH-1.4S.PS2, test 2
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
4
5
6
2
3
0 V
0 V
Multimeter
(Ω )
Multimeter
(Ω )
10+
12+
11-
Proof Test
Multimeter
(Ω )
2
3
Multimeter
(Ω )
Figure 4.3 Proof test set-up for KFD0-RSH-1.4S.PS2, test 3
4
5
6
10+
11-
12+
24 V
24 V
14
Figure 4.4 Proof test set-up for KFD0-RSH-1.4S.PS2, test 4
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Proof Test
Multimeter
(Ω )
2
3
Multimeter
(Ω )
Figure 4.5 Proof test set-up for KFD0-RSH-1.4S.PS2, test 5
Only if all tests are successfully done, the proof test is successfull.
4
5
6
7
8(+/-)
24 V
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Abbreviations
5 Abbreviations
FMEDA Failure Mode, Effects and Diagnostics Analysis
HFT Hardware Fault Tolerance
PFD
avg
PFH Probability of dangerous Failure per Hour
PTC Proof Test Coverage
SFF Safe Failure Fraction
SIF Safety Instrumented Function
SIL Safety Integrity Level
SIS Safety Instrumented System
T
proof
DPS Dual Pole Switching
DTS De-energized To Safe State
ESD Emergency Shut Down
ETS Energized To Safe State
Avera ge Probability of Failure on Demand
Proof Test Interval
16
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SAFETY MANUAL SIL KFD0-RSH-1.4S.PS2
Notes
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Subject to modifications
Copyright PEPPERL+FUCHS • Printed in Germany
www.pepperl-fuchs.com
Worldwide Headquarters
Pepperl+Fuchs GmbH
68307 Mannheim · Germany
Tel. +49 621 776-0
E-mail: info@de.pepperl-fuchs.com
For the Pepperl+Fuchs representative
closest to you check www.pepperl-fuchs.com/pfcontact
PROCESS AUTOMATION –
PROTECTING YOUR PROCESS
225538 TDOCT-2052CENG
04/2011
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