Translation Supplementary requirements for the testing and certification of Safety relays

Transcription

1 Translation Supplementary requirements for the testing and certification of Safety relays Status as of / Principles of testing Safety relays GS-ET-20 Expert committee for electrical engineering Testing and certification facility in DGUV Test Gustav-Heinemann-Ufer Cologne, Germany GS-ET-20 GS-ET-20 Safety relays Page 1 of 20

2 These Principles of testing serve as verification that the requirements of the German Product Safety Act (ProdSG) and, as such, the 1st and 9th provisions of the ProdSG in particular, have been complied with in connection with DIN EN These principles will be revised and supplemented periodically in consideration of knowledge gained in the area of occupational health and safety, as well as technical progress. The most recent edition shall always be binding for tests conducted the Electrical engineering testing and certification body. GS-ET-20, Principles of testing, Edition , is to be applied as of Feb. 01, 2017 and replaces Edition These Principles of testing supplement the requirements and tests set forth in DIN EN for safety switches with additional requirements. Changes with respect to Issue: updated: Technical rules updated: PFH D eliminated; operating environment area specified: Test fluid reworked: Impact testing reworked: Vibration testing reworked: Shock testing reworked: Testing updated: Standards denoted, measurement specified reworked: Testing Annex A: Annex B: Standard updated PFH D eliminated GS-ET-20 Safety relays Page 2 of 20

3 Table of Contents Page 1 General Scope Technical rules 5 2 Terms General Safety function Electrical relay Switching relay with positively driven contacts 6 3 Documents and prototypes for submission Technical documentation Product specifications Prototype 7 4 Type testing General test requirements Product information Markings Minimum information on the Safety relay Size of graphic symbols, lettering and digits Durability Position Completeness of information Mechanical testing Impact testing Vibration testing Shock testing Thermal load capacity of insulating components 12 GS-ET-20 Safety relays Page 3 of 20

4 Page 4.6 Air gaps and creepage distances Verification of adherence to excess temperature limits Protection against electric shock Dielectric strength Internal wiring Suitability of components used Component installation Delay time for fail-safe contacts Fail-safe contacts without release time-delay Fail-safe contacts with release time-delay Fault characteristics Safety relays Safety relays providing contact expansion in already existing devices according to Section EMC requirements External materials and properties 17 Annex A Value determination for the mean annual demand rate n op with missing relevant manufacturer specifications 18 Annex B Information related to contract preparation - Safety relays 19 GS-ET-20 Safety relays Page 4 of 20

5 1 General 1.1 Scope These principles of testing apply to Safety relays used in fail-safe applications. These Safety relays may contain electromechanical and/or electronic and/or programmable electronic components for the provision of the safety function. 1.2 Technical rules DIN EN ISO : DIN EN ISO : DIN EN VDE : DIN EN : DIN EN VDE : Safety of machinery; Safety-related parts of control systems Part 1: General principles for design Safety of machinery; Safety-related parts of control systems Part 2: Validation Safety of machinery Functional safety of safety-related electrical, electronic and programmable electronic control systems Electrical equipment for measurement, control and laboratory use EMC requirements Part 3-1: Immunity requirements for safety-related systems and for equipment intended to perform safetyrelated functions (functional safety) General industrial applications Electromechanical elementary relays Part 3: Relays with forcibly guided (mechanically linked) contacts Note: DIN EN (VDE ): may be used in parallel until Apr. 01, Terms 2.1 General Safety function A switchgear function triggered an input signal serving the attainment of a safe state. GS-ET-20 Safety relays Page 5 of 20

6 2.1.2 Electrical relay A device used to produce immediate, pre-determined changes in one or more electrical output circuits when certain conditions occur in the electrical input circuit that controls the device Relays with forcibly guided (mechanically linked) contacts A switching relay with at least 1 break-contact and 1 make-contact using mechanical means to ensure that the break-contact and make-contact can never be closed concurrently. 3 Documents and prototypes for submission 3.1 Technical documentation The information for commissioning, connection and operation of the Safety relay must be provided in form of drawings, circuit diagrams, tables, descriptions and user information. The following technical documents must be submitted in the German language for technical testing: - Installation instructions - Calibration instructions - User information - Sales literature (if available) - Circuit diagrams - Parts lists - Circuit board layouts - Component layout diagrams - Software documentation according to the applicable standard - Single fault analysis (e.g. FMEA) - Fault combination analysis (e.g. FTA) - Test reports from accredited bodies (if applicable) The testing facility can request further documents if needed. 3.2 Product specifications The form provided in the Annex B should be completed and submitted together with the application form. GS-ET-20 Safety relays Page 6 of 20

7 3.3 Prototype The number of prototypes to be submitted will be determined the testing body. As a rule, at least two unit prototypes must be made available. 4 Type testing 4.1 General test requirements Safety relays must satisfy all of the requirements below. The test sequence must be chosen in such a manner that earlier tests do not influence the results of subsequent tests. In case of doubt, a separate test object should be used. Fulfilment of farther reaching manufacturer specifications must be verified separately. Testing shall be conducted on Safety relays according to the rating data specified the manufacturer. Unless otherwise specified in the individual test instructions, proper functioning of the Safety relay must be ascertained prior to the initial test, and subsequent to each individual test. 4.2 Product information Product information must be provided in an official language of the community that is acceptable in the country, in which the device is to be installed. If the product information is not in German, a German translation must be provided. Testing will be conducted with reference to the German translation The devices should be accompanied user information enabling proper connection and commissioning. In addition to the requirements set forth in the standards, the user information must contain at least: a) Manufacturer's name and complete address b) Product designation c) EC Declaration of Conformity according to Annex II 1.A GS-ET-20 Safety relays Page 7 of 20

8 d) Information regarding the application of DIN EN ISO Category - PL - Demand rate with a defined load (including load specification) for components subject to wear e) Information regarding the application of DIN EN SILCL f) Specification of voltage type and frequency (if differing from 50 Hz) g) Specification of device power/current consumption h) Information regarding the protection of safety-relevant output contact current paths i) Operating environment temperature range (at least -5 to +40 C) j) Separate IP-Protection class designations may be required according to the clamping terminal area and the casing, as well as a reference to the potential need for additional installation space k) Manufacturer specifications for the conductor type (rigid, multi-strand or finestrand), the smallest and largest conductor cross-sections for which the connections are suitable and, if necessary, the number of simultaneously connectable conductors l) Information regarding response or release delays where time-delayed output contact current paths are present m) Where time-delayed fail-safe contacts are used, it must be noted that the response time may be extended or the release time may be shortened n) Simplified depiction of the internal circuitry in order to illustrate clamping terminal function (functional description) o) Depiction of wiring examples in accordance with intended proper usage p) Information regarding fault characteristics q) In the event semiconductor output switching elements are used, Annex H.5 of DIN EN must be observed r) Reference to differentiations between the electrical circuitry used for fail-safe applications and the electrical circuitry used for reporting applications GS-ET-20 Safety relays Page 8 of 20

9 s) Notice to the Safety relay user that the overall concept of the control system, into which the Safety relay is to be incorporated, must be validated. t) Information regarding the conditions under which the PL/SILCL has been determined Sales literature must not contradict the Instruction manual with respect to safety and health protection aspects. Review of the technical documents submitted; check for completeness, correctness and consistency. 4.3 Markings Minimum information on the Safety relay - Manufacturer's name and complete address - Nomenclature of the Safety relay - Type designation - Serial number if applicable - Year of manufacture, meaning the year the production process was completed - CE-marking Size of graphic symbols, lettering and digits The size of graphic symbols, characters and digits must be at least 2 mm. Visual inspection /measurement of inscriptions or type plate Durability Inscriptions must be durable. Gently rub using two cotton cloths, one soaked in water and the other in a test fluid* ), for 15 s each. The markings must remain clearly legible, while the marking label must remain firmly affixed to the unit. * ) The chemical product with the trade name "n-hexan for analysis", which fulfils the requirements for the test fluid defined in DIN EN and DIN EN , should be used as test fluid. GS-ET-20 Safety relays Page 9 of 20

10 4.3.4 Position Markings on the terminal clamps must be legible when switch- or control gear is connected. Visual inspection Completeness of information In addition to the requirements of the standard, the following information must be included: a) Rated operating voltages and type, as well as rated frequency if differing from 50 Hz, b) Protection of the operating voltage, if necessary, c) Rated operating current values at the rated output contact operating voltages, d) Symbolic allocation of terminal clamps according to their function. Check for completeness, correctness and consistency. 4.4 Mechanical testing Safety switches must possess sufficient mechanical strength with respect to expected operational demands when used as intended, such as jolting, shock or impact Impact testing The unit is to be stored for 2 h at the lowest operating environment temperature prescribed the manufacturer, after which Ehc ("vertical hammer") testing is to be performed (within 120 s) according to DIN EN as follows: Three 0.7 J blows shall be applied at the location considered to be the weakest point, where particular attention should be paid to the insulating materials used to shroud live components (contact terminals). No damage to the test specimen should be detected after testing and, in particular: 1. the specified degree of protection (IP code) must still be warranted, 2. the effectivity of the insulation material lining and isolating partitions must not be impaired, Visual inspection, Protection class testing as necessary GS-ET-20 Safety relays Page 10 of 20

11 4.4.2 Vibration testing Vibration testing is to be carried out according to DIN EN with the following test parameters: Frequency range / Amplitude 5 Hz f < 8.4 Hz / 3.5 mm Frequency range / Acceleration 8.4 Hz f 150 Hz / 10 m/s 2 Exposure duration 10 frequency sweeps in each of the 3 axes positioned perpendicular to each other Tuning speed 1 octave/min The test object function is in the active safety state, meaning its output(s) is/are opened. During testing, the switching state of the output(s) must not change. This must be monitored a measuring system capable of detecting switching state changes greater than 0.2 ms. Subsequent to testing, the specified degree of protection (IP code) must still be warranted, Air gaps and creepage distances must be maintained, Assembly component locations must remain unchanged, The device must continue to function properly according to its intended usage Shock testing Shock testing is to be carried out according to DIN EN with the following test parameters: Type of shock Half-sine wave Shock amplitude 150 m/s 2 Shock duration 11 ms Number of shocks 3 *) *) 3 successive shocks shall be applied in both directions on each of the 3 test specimen axes positioned perpendicular to each other; 18 shock exposures in total. GS-ET-20 Safety relays Page 11 of 20

12 The test object s function is in the active safety state, meaning its output(s) is/are opened. During testing, the switching state of the output(s) must not change. This must be monitored a measuring system capable of detecting switching state changes greater than 0.2 ms. Subsequent to testing, the specified degree of protection (IP code) must still be warranted, Air gaps and creepage distances must be maintained, Assembly component locations must remain unchanged, The device must continue to function properly according to its intended usage. 4.5 Thermal load capacity of insulating components Insulating components (enclosures, live part mountings) must be sufficiently resistant to heat and fire. Insulating materials used to affix in place current-carrying components must be tested at a heat-filament temperature of 750 C in accordance with DIN EN to DIN EN with all other insulating materials being tested at 650 C. 4.6 Air gaps and creepage distances Air gap and creepage distance dimensioning should be based on: Overvoltage category III Contamination level 2 as a minimum. The values specified in DIN EN , Tables 13 and 15 must be maintained as a minimum between the mains circuits, the control circuits and the contact circuits (safety-relevant contact current circuits or signal circuits), as well as between various contact current circuits themselves with consideration given to DIN EN , Table H.1. Interfaces intended for connection to external data processing equipment (external displays, buses, modems, etc.) or communications equipment shall be reliably isolated from terminals and live circuits with potentially hazardous voltages upon physical contact (see DIN EN , Annex N). GS-ET-20 Safety relays Page 12 of 20

13 Measurement Exception for printed circuits with basic insulation: If the air gap and creepage distance values are lower than those stipulated above, the following test should be performed: Clearances down to 1.5 mm are acceptable for the basic insulation up to 300 V, if the use of suitable insulating shrouding with appropriate insulating properties is warranted, if the dielectric strength test below is passed and, consequently, if the same level of safety is maintained. Measurement of air gaps and creepage distances and, if necessary, execution of the testing below: Affected conductors, between which the air gaps and creepage distances are not maintained, as well as the conductor paths protected insulating shrouding because of insufficient clearance distances, are to be subjected to surge voltage testing. This test is comprised of three impulses for each polarity at a surge voltage of 1.2/50 µs with a pause of at least 1 s between pulses corresponding to the test voltage in accordance with DIN EN , Table H.1 and Table 12. There must be no occurrence of flashover or dielectric breakdown during testing. For practical purposes, testing shall be performed on a bare printed circuit board. NOTE: When used in printed circuit boards, epoxy glass fibre is a Group IIIa insulating material and has a CTI value of 175 CTI < 400. If a design clearance distance between conductor paths is less than 1.5 mm, acceptance of the reduced clearance requires additional verification that the shroud coating used is comparable with Type 2 according to VDE 0110 Part Verification of adherence to excess temperature limits For analysis of temperature increase, the upper ambient temperature of the Safety relay must a) correspond to manufacturer specifications in the User manual or b) if no information is available, 40 C shall apply as a minimum. GS-ET-20 Safety relays Page 13 of 20

14 If heat testing is carried out at room temperature, the temperature increase ascertained must be increased the temperature difference ascertained between the upper ambient (manufacturer s specifications) and room temperatures. 4.8 Protection against electric shock Measures must be taken to protect against direct as well as indirect physical contact. The device must correspond to Protection class IP 2X as a minimum. This requirement does not apply to devices with open-type design featuring setting or control elements: in such cases, the Instruction manual shall indicate that the device must be installed with particular consideration given to clearance distance requirements according to DIN EN Plug connectors which may carry voltages hazardous to physical contact and which can be loosened without the use of tools must correspond to at least IP 2X in the loosened state. Visual inspection of the Safety relay 4.9 Dielectric strength In addition to the requirements of DIN EN : , Section , Safety relays shall be stored for 96 h at a temperature of 40 (± 2) C and an atmospheric humidity of 93 (+2/-3)% prior to verification of power frequency dielectric strength. Subsequent to testing, a 1 hour period at room temperature should be observed. According to DIN EN : , Section For Safety switches with Protection class II, a test voltage must be selected in accordance with DIN EN , Section F Internal wiring Insulated conductors must be dimensioned at least for the rated insulation voltage and the anticipated current loading. Visual inspection, measurement; compare with DIN VDE Insulated conductors must not come into contact with bare live parts of differing potential or with sharp edges; they must be fixed in a suitable manner. Visual inspection. GS-ET-20 Safety relays Page 14 of 20

15 Internal connections must be configured in such a manner that they are able to withstand anticipated mechanical and electrical loads. Visual inspection of the contact points As a rule, printed circuit board material is to be made of glass fibre reinforced epoxy resin. Suitable protection against corrosion must be warranted. Visual inspection of the printed circuit board Suitability of components used Each component must be employed in accordance with its rating data and be suitable for the purpose intended. Check the corresponding data sheets or calculate, as necessary Component installation Removable plug connectors used to connect external lines must be coded in such a manner that the risk of their inadvertent swapping is reduced to a minimum. Visual inspection and measurement Delay time for fail-safe contacts Fail-safe contacts without release time-delay Drop-out times for fail-safe contacts shall not exceed 200 ms. Measurement of the contact fall time at the tolerance limits specified for the operating voltage Fail-safe contacts with release time-delay A time-delay of up to 30 s is acceptable for Category 3 and 4 or Performance Level d and e fail-safe contacts in accordance with DIN EN ISO , as well as for SILCL 2 and SILCL 3 contacts in accordance with DIN EN If this specified maximum delay-time be exceeded, the following requirements must be met: a) Simultaneous monitoring of the two timing channels must be observed. GS-ET-20 Safety relays Page 15 of 20

16 b) The simultaneous monitoring must be within an interval of ± 5% of the selected time-delay, and must prevent a reenergizing of the assembly in the event this interval is not observed. Measurement of the release time-delay, review of the circuit documentation Fault characteristics Safety relays A check should be made to determine whether the Safety relay satisfies the safetyrelevant parameters as prescribed the manufacturer according to DIN EN ISO or DIN EN In so doing, all Safety relay usage variants as specified the manufacturer must be taken into account. If information regarding the mean annual demand rate is not available, the specifications as set forth in Annex A should be applied. NOTE: Usage variants in the sense of this provision refer to the circuit and/or configuration variants as specified the manufacturer (e.g. cross-short-circuit detection, single or multi-channel actuation, contact feedback, turning speed monitoring, timedelay adjustment). Validation according to DIN EN ISO or DIN EN Safety relays for contact expansion on existing devices in accordance with Section These devices must function in such a manner that a single fault event will not prevent the breaking of safety-relevant circuits. The devices must feature a feedback circuit, which can be incorporated into the switching conditions (e.g. terminals clamps X1, X2) of a higher-level device in accordance with Section Validation according to DIN EN ISO or DIN EN GS-ET-20 Safety relays Page 16 of 20

17 4.15 EMC requirements In addition to the requirements of DIN EN related to immunity to interference, Safety relays must also satisfy the requirements of DIN EN See DIN EN External materials and properties Insofar as functionally practicable, any physically accessible piece of equipment must be free of sharp corners, edges or abrasive surfaces that can cause potential injury. Corners and edges must be deburred and surfaces must be smooth to the touch. Handling and visual inspection. GS-ET-20 Safety relays Page 17 of 20

18 Annex A Determination of the value for the mean annual demand rate n op with missing relevant manufacturer specifications If the applicant does not provide information related to the mean annual demand rate n op according to DIN EN ISO : , Section C.4.2, Form C.2, the following values listed for n op will be applied, dependent on the system application(s) identified in the user Information manual: Application as d op in [days/a] h op in [h/day] t cycle in [s/cycle] 1) h op in [cycles/a] Emergency-Stop device 365 2) 24 2) ) 12 Safety door monitoring Contact-free protective equipment Two-hand device ) 2) The values for t cycle represent worst case values In this context, it is assumed that the function of a permanently available emergencystop device is tested at regular intervals (see 3 Section 3 of the German Ordinance on Industrial Safety and Health [BetrSichV]) Legend: d op Mean operating time in days per year h op Mean operating time in hours per day Mean time between the start of two consecutive cycles in seconds t cycle GS-ET-20 Safety relays Page 18 of 20

19 Annex B Company: Information related to contract preparation - Safety relays - Name: Tel.: Product identification information Product nomenclature Type Product variants available? Yes / No Variant matrix attached? Yes / No Test specification(s) and parameters to be used according to test specification(s) Testing in accordance with DIN EN ISO Yes / No Category PL MTTF d in[a] DC/DC avg in [%] CCF Service life Mean operating duration d op in [points] in [years] in [days/years] Mean operating duration h op in [hours/days] Cycle time t cycle in [s -1 ] Testing in accordance with DIN EN Yes / No SILCL Service life in [years] Hardware fault-tolerance DC/DC avg in [%] SFF in [%] GS-ET-20 Safety relays Page 19 of 20

20 Documentation to be submitted Information related to contract preparation - Safety relays - attached will be submitted User information Sales literature Circuit diagram(s) Printed circuit boardlayout(s) Documentation to be submitted attached will be submitted Parts list(s) Component failure rate (if available) Single fault analysis (e.g. FMEA) Fault combination analysis (e.g. FTA) Documentation of software according to Principles of Testing not applicable Test reports provided external accredited test bodies for Electromagnetic compatibility Switch-ON/switch-OFF capacity of the safetyrelated shutdown devices Contingent short-circuit current from safetyrelated shutdown devices attached will be submitted Test reports provided for tests performed under special agreement for attached will be submitted Note: In the interest of prompt order processing, it is essential that the information above be provided in its entirety! Date Name Signature GS-ET-20 Safety relays Page 20 of 20