machines and plants with ce

Machines and Plants with CEWe support you with your CE declaration of conformity in accordance with the new machinery directive 2006/42/EC

Machinery Directive 2006/42/EC

Background information and current status of the CE declaration of conformity

Responsibility for conformance certification of CE

The new machinery directive is valid and in force in the European Union.For all machines and plants installed in the EU, the new machinery directive has to be applied.

External European manufacturers have to respect the new machinery directive for every machine / plant installed in Europe.

History and main task of the Machinery Directive 2006/42/EC

The Machinery Directive 2006/42/EC came into effect on the 29th of December 2009 with no transition period. It affects a large number of machines and partially completed machinery. Health and safety are emphasised. The machine’s manufacturer or his authorised representative is responsible for carrying out a risk assessment.This should determine the health and safety measures applicable for the machine. The machine must then be designed and built taking the results of this risk assessment into account. The machine must be designed and built so that it presents no risk to persons when it is functioning correctly, but also taking into account any foreseeable misuse which may take place during operation, adjustment or maintenance. The measures taken should have the aim of eliminating any risk throughout the planned service life of the machine. This includes the time when the machine is transported, installed, uninstalled, dismantled and disposed of.

Machine Manufacturer/Plant Manufacturer

The editor of a CE certificate needs to follow the new machinery directive 2006/42/EC: whether it relates to a manufacturer of a machine, a production line, a plant or a system integrator.

Machine Integrator/Production Line Integrator

The new standard applies to new machine, and plants, as well as modernizations of existing machines and plants.

Editor of a CE Certificate

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Example for a component (TERMOPTO)

Directive is only used for equipment used within certain low voltage limits and EMC directive.

Risk assessment in different standards

Risk analysis requirements are specified by:

ISO 12100-1 Safety of machinery –General principles for design – Risk assessment and risk reduction

EN 14121-1 Safety of machinery – Risk assessment –Part 1: PrinciplesThis part of ISO 14121 establishes general principles intended to be used to meet the risk reduction objectives established in ISO 12100-1:2003, Clause 5. These principles of risk assessment bring together knowledgeand experience of the design, use, incidents, accidents and harm related to machinery in order to assess the risks posed during the relevant phases of the life cycle of a machine

EN ISO 13849-1 (formerly EN 954-1)Safety of machinery – Safety-related parts of control systemsPart 1: General principles for design (ISO 13849-1:2006)

* CE Certificate upon former Guideline

Example for a machine

*

EXAMPLE

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Differences between EN954 and EN ISO 13849

EN954

One View- Evaluation only at one time

Simple rating into categories

EN ISO 13849-1

The new Machinery Directive is based on the life cycle model of the IEC 61508 and requires therefore the evaluation of all dangerous functions of a machine takenin relation to all the phases of the life cycle. In the EN ISO 13849-1 there is a modified risk graph to be used here.

The simple evaluation into categories (from EN 954) is replaced in the ISO 13849 with classification according to performance levels (PL). To cover the requirements of the PL, the structure plays an essential role, as was the case in EN 954.

In addition to this evaluation criterion, the norm uses three further characteristics to guarantee safety: • Component failure rates, • Diagnostic coverage (DC), and • Prevention of common cause failures (CCF).The combination of these three criteria, together with the structure of the safety system, determine whether the system complies with the PL value according to the EN ISO 13849-1 standard.

Document comprises 99 pages

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DEUTSCHE NORM

No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).

www.din.de

DIN EN 954-1

Safety of machinery –Safety-related parts of control systems –Part 1: General principles for design (DIN EN 954-1:1996)English version of DIN EN 954-1:1996

Sicherheit von Maschinen –Sicherheitsbezogene Teile von Steuerungen –Teil 1: Allgemeine Gestaltungsleitsätze (DIN EN 954-1:1996)Englische Fassung DIN EN 954-1:1996

©

www.beuth.de


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Component Failure Rates

Consideration of the structure of a machine

• The target value of a complete signal channel is maximum 100 years.

• The better the reliability of every single device, the better is the total reliability of a system and the better is the perfor-mance level.

• Weidmüller delivers the data for every component for the calculation of the MTTF/MTTFd.

Example: • MTTF of a relay: 60,000 h (4 years) • MTTF Opto: 7,419,720 h (847 years)

CalculationB10: 60.000 (for RSS relays DC-13 24 V / 2 A)n: 150,000 (1 switching/minute x 60 minutes x 10 hours x 250 days/year)MTTF = 60,000 ÷ (0.1 x 150,000) = 4 yearsIn comparison to this the opto module MICROOPTO ACTOR: MTTF = 847 years


Performance Level (PL)

Average probability of dangerous failure over time of 1 hour

a ≥ 10-5 to < 10-4

b ≥ 3 x10-6 to < 10-5

c ≥ 10-6 to 3 x 10-6

d ≥ 10-7 to < 10-6

e ≥ 10-8 to < 10-7

Example of the calculation of failure ratesFor mechanical components like relays or valves, we need the B10 / B10d va-lues for the MTTF / MTTFd calculation.

B10d = specifies the number of cycles at which 10 % of components have failed dangerously (definition according to standard EN ISO 13849-1).

MTTFd = B10d / (0.1 x n); n = switching cycles of the component per year.

MTTFd = 1/(PFH x 8760h-1)

MTTF calculation of a MICROOPTO

Parts Kind of part Reference Data source MTTF MTTF Anno-count per part for all tations13 metal film resistor .. table C.5 EN ISO 13849 570,776 43,906

4 capacitor, X7R or better C1 ... 10 table 1, SN 29500-4:2004-03 57,039 14,260

4 rectifier D2, D5 ... 7 table C.3 EN ISO 13849 57,078 14,270

2 varistor R11, R12 table 4, SN 29500-4:2004-03 114,077 57,039

3 zehner diode, < 1W D8, V1, V2 table C.3 EN ISO 13849 114,155 38,052

3 suppressor diode V3, R28, R280 table 2, SN 29500-3:2004-12 16,440 5,480

1 bipolar transistor T1 table C.2 EN ISO 13849 34,247 34,247

1 optocoupler U1 table C.7, EN ISO 13849-1:2007 7,648 7,648 *

1 IC, HC-Logic U3 table 3, SN 29500-2:2004-12 38,026 38,026

1 LED D3 table 2, SN 29500-12:2008-02 57,038 57,038

MTTF = 1,686

Several MTTF values for Weidmüller’s opto modules:

Typ MTTF/yearsMICROOPTOMOS 24 V DC /5 – 33 V DC 10 A 399

MOS 24 V DC / 12 – 300 V DC 1 A 467

MOS 24 V DC / 5 – 48 V DC 0.5 A 620

MOS 24 V DC / 8 – 30 V DC 2 A 847

MOS 12 – 28 V DC 100 kHz 1,686

MOS 5 VTTL / 24 V DC 0.1 A 2,047

MOS 12 – 28 V DC / 5 VTTL 2,559

TERMOPTOTOS/P 24 V DC / 48 V DC 0.1 A 2,500

Weidmüller opto modules feature outstanding reliability and long life-spans.

Annotations:• Calculated with the parts-count method• Clamps and connectors not taken into account• Soldering process not taken into account due to quality control processes during manufacturing• Electronic part’s failure rates increase after 8 to 12 years, so that the MTTF will decrease (see EN 61508-2, 7.4.7.4, note 3)

* Calculated as bipolar optocouplerSources for the component failure rates: Information from the component manufacturers, EN ISO 13849-1 (Safety of machinery)

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Diagnostic Coverage(DC)

Estimating the diagnostic coverage for functions and modules –only in safety circuits

Measure of the effectiveness of diagnostics, which may be determined as the ratio between the failure rate of detected dangerous failures and the failure rate of total dangerous failures.

Plausibility check using normally open and normally closed contacts of positively driven relays: DC = 99%.

Feasible when using Weidmüller’s RIDERSERIES FG relay module with a diagnostic coverage of 99 %.

Table E.1 — Estimates for diagnostic coverage (DC)

Measure DCInput device

Cyclic test stimulus by dynamic change of the input signals 90 %Plausibility check, e.g. use of normally open and normally closedmechanically linked contacts

99 %

Cross monitoring of inputs without dynamic test 0 % bis 99 %, depending on how often asignal change is done by the application

Cross monitoring of input signals with dynamic test if short circuits are not detectable (for multiple I/O)

90 %

Cross monitoring of input signals and intermediate results within the logic(L), and temporal and logical software monitor of the program flow anddetection of static faults and short circuits (for multiple I/O)

99 %

Indirect monitoring (e.g. monitoring by pressure switch, electrical position monitoring of actuators)

90 % bis 99 %, depending on the application

Direct monitoring (e.g. electrical position monitoring of control valves, monitoring of electromechanical devices by mechanically linked contact elements)

99 %

Fault detection by the process 0 % bis 99 %, depending on the application; this measure alone is not sufficient for the required performance level e!

Monitoring some characteristics of the sensor (response time, range ofanalogue signals, e.g. electrical resistance, capacitance)

60 %

Extract from EN ISO 13849-1

Components that are serving diagnostic coverage

• Relay module with forcibly guided contacts for signal monitoring in safety related circuits

• Relays with forcibly guided contacts are proven components for safety technology. They have a diagnostic coverage of 99 %.

• Contacts interlock with each other to ensures synchronous switching status.

• The feedback contact has the same status as the working contact in case of a failure (for example: working contacts melt together due to an overload).

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Avoiding common cause failures

2. Diversity Components from different manufacturers

Results: 20 Points

3. Planung, Anwendung und Erfahrung

3.1 Protection against surge voltages, over-pressure, surge currents

Results: 15 Points 3.2 Use of proven components Results: 5 Points

6. Environment 6.1 Protection against

contamination and electromagnetic interference (EMC) against common cause failures (CCF) in accordance with the appropriate standards Results: 25 Points

Total result: 65 Points

This can be achieved using Weidmüller components.

No. Measure against CCF Score1 Separation/ Segregation

Physical separation between signal paths: separation in wiring/piping,sufficient clearances and creep age distances on printed-circuit boards.

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2 Diversity

Different technologies/design or physical principles are used, for example:first channel programmable electronic and second channel hardwired,kind of initiation,pressure and temperature,Measuring of distance and pressure,digital and analog.Components of different manufactures.

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3 Design/application/experience3.1 Protection against over-voltage, over-pressure, over-current, etc. 153.2 Components used are well-tried. 54 Assessment/analysis

Are the results of a failure mode and effect analysis taken into account to avoid common-causefailures in design.

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5 Competence/trainingHave designers/ maintainers been trained to understand the causes and consequences of common cause failures?

5

6 Environmental

6.1

Prevention of contamination and electromagnetic compatibility (EMC) against CCF in accordancewith appropriate standards.Fluidic systems: filtration of the pressure medium, prevention of dirt intake, drainage ofcompressed air, e.g. in compliance with the component manufacturers‘ requirements concerningpurity of the pressure medium.Electric systems: Has the system been checked for electromagnetic immunity, e.g. as specified inrelevant standards against CCF?For combined fluidic and electric systems, both aspects should be considered.

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6.2Other influencesHave the requirements for immunity to all relevant environmental influences such as, temperature, shock, vibration, humidity (e.g. as specified in relevant standards) bee considered?

10

Total[max.achievable100]

Total score Measures for avoiding CCF a

65 or better Meets the requirementsLess than 65 Process failed ⇨ choose additional measures

Summary

Common Cause Failures(CCF)

Component failure rates• For electronic components we offer MTTF values

in online/print catalogues.• B10 values for relays are available on demand.• Solid-state relays such as

TERMOPTO / MICROOPTO have a longer MTTF in comparison to a relay (mechanical component).

Diagnostic coverage (DC)With a DC of 99%, relays with forcibly guided contacts (like the RIDERSERIES FG) are well suited for safety related applications.

Common cause failures (CCF)When system and machine manufacturers show that they prevent failures from direct or indirect lightning strikes using surge protection components, they are awarded 15 from the necessary 65 points (max. 100 points). All Weidmüller components used in a machine results in 65 points.

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Performance Level PL

Performance Level PL

The machine must be evaluated to assess its hazard or dangerous behavior to its environment (operator, user, maintenance, ...) This results in the performance level.

PL is the ability of safety-related parts to carry out their safety function under predictable conditions and to achieve the expected risk reductions.

Then every component, that is involved in the security of the machine must be adapted to the performance level.

The highest level is PL e

The PL is determined by estimating the following parameters:

• MTTFd value of the individual components less than or greater than PHF.

• The DC (diagnostic coverage) • The CCF (avoidance of Common Cause Failures) • The structure (category)

of the behaviour of the safety function under failure conditions

To calculate this, the following parameters must be considered:

Source: ZVEI „Safety of machines - clarification of the application of the standards EN 62061 and EN ISO 13849-1”

ParametersEN ISO 13849-1

Meaning

Cat. Category (B, 1, 2, 3, 4)The configuration of the hardware structure of the system to achieve a specific PL.

PL Performance Level (a, b, c, d, e)

MTTFd Time until dangerous failure or dangerous event

B10d

Number of cycles in which 10% of a sample testing of electromechanical and pneumatic components subjectto wear has been a dangerous failure

DC Diagnostic coverageCCF Common cause failureTM Mission time


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Example – machining centre with safety cover

Risk:• The work piece is inserted manually.• The machine only is allowed to run when the shield cover

is completely closed!• Assess the dangerous functions and judge the

performance level!

By the use of the risk graph, the classification of the hazard is performance level “e”

Risk Assessment

Risk graph for determining required PL for safety function

a

b

c

d

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L

1

S1F1

P1

PLr

P2

P1

P2

P1P2P1P2

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Key:1 starting point for evaluation of safety

function’s contribution to risk reductionL low contribution to risk reductionL high contribution to risk reductionPLr required performance level

Risk parameters:S severity of injuryS1 slight (normally reversible injury)S2 serious (normally irreversible injury or death)

F frequency and/or exposure to hazardF1 frequent-to-less-often and/or

exposure time is shortF2 frequent-to-continous and/or exposure time

is longP possibility of avoiding hazard or

limiting harmP1 possible under specific conditionsP2 scarcely possible


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Implementing the Measures


Control of open/closing the safety cover with SIL relay and FG (Example)

Combining the values

MTTFd = 1736 years (given)CCF = 80% (given)DC = 99% (given)PFHd = 2.47x10-8

Input

Safetylimit switch

Logic

PL e (Cat. 4)CCF = (unknown)DC = 99% (given)PFHd = 2.31x10-9

Safety relay

Output

MTTFd = 2397 yearsCCF = 80% (given)DC = 99% (given)PFHd = 2.47x10-8

RIDERSERIES FG

Values are taken out of table K.1 from EN ISO 13849-1

Calculation of MTTFdMTTFd = B10d/(0.1 x n)B10d = 2.1x106 yearn = 8760 cycles/yearMTTFd = 2.1 x 106 cycles (0.1 x 8760 cycles/year)MTTFd = 2397.26 years

Performance Level (PL)

Average probability of dangerous failure over time of 1 hour

a ≥ 10-5 to < 10-4

b ≥ 3x10-6 to < 10-5

c ≥ 10-6 to 3x10-6

d ≥ 10-7 to < 10-6

e ≥ 10-8 to < 10-7

Overall result: PL e

PFHd = 2.47 x 10-8

PFHd = 2.31 x 10-9 +PFHd = 2.47 x 10-8 +PFHd = 5.17 x 10-8

feedback looppower

motor starter

RIDERSERIESFG

Safety limitswitches

Safety relay

Input Logic Output

L1

L2

C

Architecture is category 4 in accordance with EN ISO 13849-1

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• The machine directive is valid for every machine or plant manufacturer or system integrator in order to get a CE-mark for his product.

• There are three main changes to the former valid guideline:

• Life cycle model from IEC 61508: Risk graph is needed

• Classification into performance levels

• Consideration of the structure of the machine • For electronic components we offer MTTF values

in online/print catalogues. • B10 values for relays are available on demand. • Solid-state relays such as TERMOPTO / MICROOPTO

have a longer MTTF in comparison to a relay (mechanical component).

• With a DC of 99%, relays with forcibly guided contacts like RIDERSERIES FG are well suited for safety related applications.

• When system and machine manufacturers show that they prevent failures from direct or indirect lightning strikes using surge protection components, they are awarded 15 from the necessary 65 points (max. 100 points). All Weidmüller components in a machine results in 65 points.


Results

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Increasing the Availability byUsing Components with High Reliability

The introduction of the new Machinery Directive 2006/42/EG brings with it fundamental changes to risk assessment and risk reduction. As a competent partner for the machine-building industry Weidmüller supports its customers to help them comply with the new requirements. That includes the provision of all values for relays and opto modules which are required for a conformity assessment procedure according to the 2006/42/EG directive.The new directive, which was transposed into German law by the Machinery Act, confronts automation engi-neers and machine builders with the task of undertaking a conformity assessment procedure to determine the safety of the machine. In order to be able to make binding statements with regard to the failure probability of sys-tems and individual signal lines engineers require so-called MTTF values. The statistical key indicator MTTF stands for “Mean Time To Failure”, which denotes the average operating time until a failure or malfunction occurs.

Long operational lifetime and high reliability of solid-state relays

Weidmüller establishes the values for the availability of its active components utilising the “parts count method”, according to which the failure rate of a system is calculated assuming connection in series. “A long operational lifetime and high levels of reliability are distinguishing characteristics of our relays and opto modules, even when they are subjec-ted to shock and vibration,” explains Frank Polley, product manager at Weidmüller. “For example,

we have established an MTTF value of 2,500 years for an opto module from our TERMOPTO family of products.”Users benefit from the fact that the relays and optos are compact by design, require a low control power and boast very short pick-up times. Nevertheless, despite these charac-teristics and outstanding MTTF values it is necessary to uti-lise conventional electro-mechanical relays in some applica-tions. They have significantly lower losses in the load current path and because they can tolerate AC and DC power in the load current path they are suitable for universal deployment.As relay wear is not simply a question of the quality of the module, but depends much more on its concrete use, a spe-cial variable is used to calculate their failure probability.

B10 values for the most diverse of application situations

“The B10 value is used to calculate the failure probability of modules, such as relays, which are subjected to extreme mechanical loads,” explains product manager Joachim Janik. “Put simply, this value is the number of switching opera-tions that the relay is expected to perform until ten percent of the relays fail in a given application. Parameters such as switching current, switching voltage and the type of load are substantial factors.” Consequently, the B10 value cannot generally be given for a certain type of relay, but rather in

Exemplary calculationB10: 60.000 (for RSS relays DC-13 24 V / 2 A)n: 150.000 (1 switching/minute x 60 minutes x10 hours x 250 days/year)MTTF = 60.000 ÷ (0.1 x 150.000) = 4 yearsIn comparison to this the opto moduleMICROOPTO ACTOR: MTTF = 847 years

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conjunction with the respective application. “We are able to gather a large number of B10 values for different relays, which we are pleased to make available our customers upon request. To serve all customer requests, we continually increase our collection,” says Mr Janik. The mean operating time until a relay fails can be calculated with the aid of the following formula: MTTF = B10 ÷ (0.1 x n). The value “n” represents the number of yearly switching operations in the

application. Users need only enter this value in the formula along with the appropriate B10 value to calculate the failure probability of the relays utilised in his application.

Adhering to standards begins with control and drive technology

For the machine and systems builder adhering to the new standard begins with reducing risks in control and drive technology applications, as these are the source of the greatest risks. By disclosing and making available all values necessary to perform a conformity assessment Weidmüller supports users in the fields of application in which its relays and opto modules are utilised.

Several MTTF values for Weidmüller’s opto modules:Type MTTF/yearsMICROOPTOMOS 24 V DC / 5 – 33 V DC 10 A 399

MOS 24 V DC / 12 – 300 V DC 1 A 467

MOS 24 V DC / 5 – 48 V DC 0.5 A 620

MOS 24 V DC / 8 – 30 V DC 2 A 847

MOS 12 – 28 V DC 100 kHz 1.686

MOS 5 VTTL / 24 V DC 0,1 A 2.047

MOS 12 – 28 V DC / 5 VTTL 2.559

TERMOPTO

TOS/P 24 V DC / 48 V DC 0.1 A 2.500


MICROOPTO – opto module with numerous functions for industrial applications

TERMOPTO – compact, terminal-sized opto module

Die schraublose Anschluss technologie PUSH IN reduziert die Verdrahtungszeit von TERMOPTO.

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The pluggable surge protection modules VARITECTOR SPC for two analogue or four binary signals in measurement and control

circuits have integrated error detection and error reporting

SILSUITABLE

61508


Prevention from Common Cause Failures with Surge Protection

The introduction of the new Machinery Directive 2006/42/EC brings with it fundamen-tal changes to risk assessment and risk reduction. As a com-petent partner to the mechanical and systems engineering industry Weidmüller supports its customers by helping them comply with the new requirements. Offering high-quality surge protection modules is a part of this to prevent failu-res due to common causes. The new directive, which was transposed into German law by the Machinery Act, confronts automation engineers and machine builders with the task of undertaking a conformity assessment procedure to determi-ne the safety of the machine. A requirement resulting from the Machinery Directive is the avoidance of common cause failures (CCFs) in regards to machine safety as described by the EN ISO 13849-1 standard.

Reliable protection against surge voltages

Reliable protection against surge voltages is one of the mea-sures suitable for the prevention of common causes.“When system and machine manufactures show that they pre-vent failures from direct or indirect lightning strikes using surge protection components, they are awarded 15 from the maximum 100 points under the evaluation schedu-

le of the Machinery Directive,” informed Ralf Güthoff, a product manager from Weidmüller.“This is already a quarter of the 65 points that need to be achieved to meet the requirements regarding CCF avoi-dance.” Weidmüller’s range of lightning and surge protection devices includes protection modules for energy, measure-ment and control, and the data application fields. The com-ponents comply with the new standards. The VARITECTOR SPC pluggable surge protection module for measurement and control signals provides the defined protection classes D1, C2 and C1 as specified in IEC 61643-22 and contains an internal monitoring function that regulates error detection and the error message processes. If a short-circuit occurs on the signal line or a connection is wired incorrectly the arrester enters an overload failure mode as required in the latest version of IEC 61643-21. With this functionality, the VARITECTOR SPC helps machine and systems manufactu-rers to prevent the failure of other components (common cause failure).

Lightning and surge protection components of type PU I to III impress with their high levels of discharge current and their compact design.

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Failure rates for VARITECTOR SPCType

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λ ges FIT value

1/λ ges MTTF

(MTTF x 109)8,760 hours

VSPC CL 13.6 29.45 0.00 1.95 45.0 0.0222 2,537

VSPC CL …R 17.1 57.40 0.00 3.70 78.2 0.0128 1,460

VSPC CL HF 15.6 30.45 0.00 2.95 49.0 0.0204 2,330

VSPC CL HF …R 19.1 58.40 0.00 4.70 82.2 0.0122 1,389

VSPC SL 6.0 27.10 1.00 8.90 43.0 0.0233 2,655

VSPC SL …R 9.5 55.05 1.00 10.65 76.2 0.0131 1,498

VSPC 3/4 WIRE 36.0 107.00 0.00 7.00 150.0 0.0067 761

VSPC RS485 12.0 31.75 9.00 4.25 57.0 0.0175 2,003

VSPC RS485 …R 15.5 59.70 9.00 6.00 90.2 0.0111 1,266

VSPC TELE Uk0 15.6 30.45 0.00 2.95 49.0 0.0204 2,330

VSPC 1CL PW 13.6 29.45 0.00 1.95 45.0 0.0222 2,537

VSPC GDT 2CH 6.0 5.00 0.00 0.00 11.0 0.0909 10,378

VSPC MOV 2CH 2.5 22.75 0.75 0.00 26.0 0.0385 4,391

VSPC MOV 2CH …R 2.5 73.95 0.75 0.00 77.2 0.0130 1,479

VSPC TAZ 2CH 2.5 24.25 5.25 0.00 32.0 0.0313 3,567

VSPC TAZ 4CH 2.5 24.25 5.25 0.00 32.0 0.0313 3,567

Failure rates: low and transparent

“To establish the failure rate of our VARITECTOR SPC modules we make the Lambda or thermal conductivity values available. These are expressed as ‘FIT’ – Failure In Time figures, where 1 FIT corresponds to a single failure in a billion hours. A rule of thumb is: the lower the Lambda value, the less frequent failures occur,” explained Ralf Güthoff. The total number of all failures comprises the “non-hazardous,” i.e. not safety-related failures, and the “hazardous” failures. Weidmüller provides FIT values that are broken down exactly into these classifications; they show exactly what sort of failure they refer to, this allows the user to be able to accurately classify machine safety with re-gards to the surge protection that is incorporated. “If you divide 1 by the sum of the failure rate values, you get the MTTF (MeanTime To Failure) value, which is the average operational time to the first failure of electronic and electromechanical compo-nents,” Ralf Güthoff continued. “Worked out in terms of wor-king years, our surge protection components have an averageof just over 3,000 years MTTF, this is excellent and they can be

regarded as a reliable way to reduce failures due to common causes.”

VARITECTOR SSC for the protection of measurement and control circuits in a compact terminal block format

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Weidmüller – the Industrial Connectivity Partner.

As experienced experts we support our customers and partners around the world with products, solutions and services for energy, signals and data in an industrial environment. We are at home in their industries and markets and understand the technological challenges of tomorrow. Thus we are continuously developing innovative, sustainable and useful solutions for their individual needs. Together we set standards for Industrial Connectivity.

Weidmüller Interface GmbH & Co. KGKlingenbergstraße 1632758 Detmold, GermanyT +49 5231 14-0F +49 5231 [email protected] 1368350000/04/2012/SMKW

We cannot guarantee that there are no mistakes in the publications or software provided by us to the customer for the purpose of making orders. We try our best to quickly correct errors in our printed media. All orders are based on our general terms of delivery, which can be reviewed on the websites of our group companies where you place your order. On demand we can also send the general terms of delivery to you.

machines and plants with ce

Documents

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principles of risk assessment

machine plant

design risk assessment

emc directive

ecmachinery directive

risk reductionen

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