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2、rom, is the sole responsibility of the user.”SAE reviews each technical report at least every five years at which time it may be revised, reaffirmed, stabilized, or cancelled. SAE invites your written comments and suggestions.Copyright 2016 SAE InternationalAll rights reserved. No part of this publi
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4、side USA)Fax: 724-776-0790Email: CustomerServicesae.orgSAE WEB ADDRESS: http:/www.sae.orgSAE values your input. To provide feedbackon this Technical Report, please visithttp:/www.sae.org/technical/standards/ARD6888AEROSPACERESOURCE DOCUMENTARD6888Issued 2016-07Functional Specification of MiniatureCo
5、nnectors for Health Monitoring PurposesRATIONALEData is the raw material to develop health monitoring functions. But due to the data acquisition chain, collecting data can have a negative impact on weight and complexity. One of the significant contributors to the weight of the data acquisition chain
6、 is the connectors. Connectors qualified for the severe environments such as for propulsion systems can be bulky and heavy. Some might argue that wireless communication is a solution, but wireless communication is not always preferable. Moreover, even for wireless communications connectors can be ne
7、cessary. In order to collect more data and develop health monitoring functions with minimum impact on weight, it appears necessary to reduce the size of connectors.FOREWORDThis document specifies the functional needs associated with miniature connectors dedicated to health monitoring. It is mainly a
8、ddressed to the SAE committee specializing in connectors (AE-8C1) in order to assess the opportunity for developping a new Aerospace Standard. SAE INTERNATIONAL ARD6888 Page 2 of 13TABLE OF CONTENTS1. SCOPE 3 1.1 Purpose. 3 1.2 Specification Methodology 3 2. REFERENCES 3 2.1 Applicable Documents 3 2
9、.2 Acronyms and Abbreviations 4 3. PIN, SIZE AND DESIGN REQUIREMENTS. 4 4. ELECTRICAL REQUIREMENTS 6 5. TEMPERATURE REQUIREMENTS. 10 6. VIBRATION REQUIREMENTS. 11 7. OTHER QUALIFICATION REQUIREMENTS. 12 8. NOTES 13 8.1 Revision Indicator 13TABLE 1 MINIMUM ATTENUATION FOR SHIELDING EFFECTIVENESS 7 FI
10、GURE 1 WAVEFORM 5A CHARACTERISTICS 7 FIGURE 2 PIN CONNECTOR CURRENT SET UP . 8 FIGURE 3 PIN CONNECTOR VOLTAGE SET UP 9 SAE INTERNATIONAL ARD6888 Page 3 of 131. SCOPE1.1 PurposeThe purpose of this document is to specify the functional requirements for a miniature connector to be used for health monit
11、oring purposes on aircraft (including harsh environments such as found in propulsion systems). It is actually a family of miniature connectors that is specified in this document for various uses (e.g., pin counts) and environments. This specification will be used by the SAE committee for connectors
12、(AE-8C1) to study the feasibility of developing a dedicated connector standard.1.2 Specification MethodologyThe approach used to specify requirements for standard miniature connectors qualified on propulsion systems is to use the connector standard EN 2997 as a reference.EN 2997 is used on large civ
13、ilian aircraft as the applicable connector standard for severe environments (e.g., the engine). Compliance with the environmental requirements of EN 2997 appears as proper requirements to withstand severe environments. The connector standard EN 2997 is derived from MIL-DTL-83723F Series III, Type T.
14、 It is particularly suitable for use on aircraft engines and in other zones of severe operating conditions.Nevertheless, in order to reduce the connector size (and cost), it is necessary to look at all the functional characteristics of health monitoring and exclude the requirements that do not apply
15、 for such application (e.g., it is not necessary to remain functional in case of fire).2. REFERENCES2.1 Applicable DocumentsThe following publications form a part of this document to the extent specified herein. The latest issue of SAE publications shall apply. The applicable issue of other publicat
16、ions shall be the issue in effect on the date of the purchase order. In theevent of conflict between the text of this document and references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exem
17、ption has been obtained.2.1.1 AECMA PublicationsThe European Association of Aerospace Industries Standardization, Gulledelle 94, B-1200 Brussels, Tel. + 32 2 775 8110, Fax. + 32 2 775 8111, www.aecma-stan.org.EN2997 “Aerospace series Connectors, electrical, circular, coupled by threaded ring, fire-r
18、esistant or non fire-resistant, operating temperatures -65 to 175 C continuous, 200 C continuous, 260 C peak”, dated June 2005EN2591 “Aerospace series Elements of electrical and optical connection, test methods”, dated August 19982.1.2 RTCA PublicationsAvailable from RTCA, Inc., 1150 18th Street, NW
19、, Suite 910, Washington, DC 20036, Tel: 202-833-9339, www.rtca.org.DO-160G “Environmental Conditions and Test Procedures for Airborne Equipment”, dated December 2010SAE INTERNATIONAL ARD6888 Page 4 of 132.2 Acronyms and AbbreviationsA AmpereAECMA European Association of Aerospace Industriescm Centim
20、eterC Degree CelsiusFBO Fan Blade Outg Gravity constant (9.81 m/s2)IEEE Institute of Electrical and Electronics EngineerskA KiloamperemA MilliampereM Megaohmm MilliohmkPa KilopascalPoE Power over Ethernetr.m.s. Root Mean SquareVVoltWWatWF Waveform3. PIN, SIZE AND DESIGN REQUIREMENTSRequirement #3.1
21、- Number of pins:The number of pins included in the various models of this family of connectors shall vary between 1 and 10.Rationale: Various types of connections will be applicable for this family of connectors. It is anticipated that a connector with more than 10 pins will be too large to be cons
22、idered as miniature one, nevertheless this assumption could be modified in the future.Requirement #3.2 - Connector size:The dimensions of the connector shall be minimized with a target of 0.5 cm for its maximum footprint on support element (i.e., maximum diameter of connector if footprint is circula
23、r) for a connector with 4 pins, or 1 cm for a connector with 10 pins. Rationale: In order to reduce impact on support element size, the connector dimensions should be minimized. The requirement of 0.5 cm or 1 cm for its largest dimension is not driven by any rigid constraint, it is the target to aim
24、 for. SAE INTERNATIONAL ARD6888 Page 5 of 13Requirement #3.3 - Connector compatibility:The connector and pins shall be compatible at a minimum with printed circuit board mount, and bulkhead mount (mounted on exterior panel), so that a cable can be crimped and/or soldered on (cable end mount). Ration
25、ale: This family of connector is intended to have a wide range of applications.Requirement #3.4 - Pins connection with an electronic unit:Pins connection with an electronic unit shall have minimum impact on the size of this electronic unit. Soldering connector pins on the printed circuit board and u
26、sing bent (right angle) pins can reduce the impact of connectors on the size of the electronic unit.Rationale: To reduce the impact of connectors on the size of the electronic unit (on which miniature connectors can be installed).Requirement #3.5 - Latching mechanism:The connector shall have a latch
27、ing mechanism. Rationale: To remain functional under vibration. Requirement #3.6 - Polarization: The connector shall be polarized to prevent mismating, such that the mechanical keying features engage before the electrical contacts. Rationale: To avoid incorrect assembly and degradation of the connec
28、tor and/or pins. -INFORMATION-Information #3.1 - Pin size: Pin size should be defined by connector size constraints and electrical requirements. Nevertheless a size 26 or 28 will probably be suitable. Information #3.2-Connector shape:There is no requirement concerning the overall shape of the connec
29、tor. It could be circular or have any other shape as long as all the requirements of this specification are fulfilled.Information #3.3 - Mating type:There is no requirement concerning the connector mating type. It could be coupled by threaded ring or any other mating type as long as the requirements
30、 of this specification are fulfilled (particularly performance under shock and vibration conditions). Nevertheless, the mating type must be reviewed carefully to verify that it complies with this functional specification and that it is suited for health monitoring applications on-board aircraft.SAE
31、INTERNATIONAL ARD6888 Page 6 of 134. ELECTRICAL REQUIREMENTSRequirement #4.1 - Maximum operating conditions:The connector shall be able to operate at the following maximum operating conditions (compliant with “Power over Ethernet +”, Institute of Electrical and Electronics Engineers (IEEE) 802.3 at)
32、: x Maximum power delivered by power source: 30 Wx Maximum voltage delivered by power source: 57 Vx Maximum current delivered by power source: 2 ARationale: PoE (Power over Ethernet) is a wide spread standard. Moreover, PoE+ provides more power than basic PoE (about 25W instead of 12W), allowing eve
33、n more devices to be attached to the connector.Requirement #4.2 - Housing (shell) electrical continuity:The connector shall comply with EN2591-205 on housing electrical continuity with the conditions given in EN2997 for FODVVHV66( PDLPXPUHVLVWDQFHP Rationale: Consistent with connector EN2997, qualif
34、ied on propulsion systems. Requirement #4.3 - Insulation resistance:The connector shall comply with EN2591-206 on insulation resistance with the conditions given in EN2997 (minimum LQVXODWLRQUHVLVWDQFHDWDPELHQWWHPSHUDWXUH0 Rationale: Consistent with connector EN2997, qualified on propulsion systems.
35、 Requirement #4.4 - Voltage proof:The connector shall comply with EN2591-207 on voltage proof with the conditions given in EN2997 (withstand voltage at sea level: 1500 V r.m.s.).Rationale: Consistent with connector EN2997, qualified on propulsion systems. Requirement #4.5 - Shielding:The connector (
36、including outer shell) shall be shielded.The connector backshell shall be connected to cable shielding with a resistance strictly sPDOOHUWKDQPRationale: Consistent with connector EN2997, qualified on propulsion systems. SAE INTERNATIONAL ARD6888 Page 7 of 13Requirement #4.6 - Shielding effectiveness
37、:The connector shall comply with EN2591-213 on shielding effectiveness with the following conditions: Table 1 Minimum attenuation for shielding effectivenessFrequency (MHz) Minimum attenuation (dB)100 90200 88300 88400 87800 851000 85Rationale: Consistent with connector EN2997, qualified on propulsi
38、on systems.Requirement #4.7 - Lightning WF 5A/shielding testThe connector shall comply with EN2591-214 on lightning with the waveform characteristics, peak current levels and pass/fail criteria given below.Waveform (WF) characteristics (WF 5A):Figure 1 - Waveform 5A characteristicsPeak current level
39、s applicable (depending on connector model): x Level A: 40 kAx Level B: 15 kAx Level C: 5 kASAE INTERNATIONAL ARD6888 Page 8 of 13Pass/fail criteria (all shall be verified):x No tool shall be used for mating/unmating the connector.x The connector shall comply with EN2591-101 (visual inspection).x Th
40、e connector shall comply with Requirement #4.2 - Housing (shell) electrical continuity with a measured value after the test less than 5% above initial value.Rationale: Recent large commercial aircraft use composite materials in the primary structure instead of metal. It changes the waveform and incr
41、eases the energy of lightning strikes that aircraft components have to cope with. As the EN2997 was not up-to-date concerning these new lightning waveforms and levels, this requirement was added.Requirement #4.8 - Lightning WF 5A/pins testThe connector shall comply with DO-160G 22.5.1 on pin injecti
42、on tests with the procedure, test levels and pass/fail criteria given below.Test procedure: x The tests shall be performed with the current/voltage waveform 5A.x Both voltage and current test level shall be applied to the connector.x $KLJKSRZHUJHQHUDWRURIVKDOOEHXVHGx The waveform shall be applied di
43、rectly between each pin and case ground.x The test setups shown in Figures 2 and 3 below shall both apply:Figure 2 - Pin connector current set upSAE INTERNATIONAL ARD6888 Page 9 of 13Figure 3 - Pin connector voltage set upTest levels applicable (depending on connector model): x Level A: 2000V/2000Ax
44、 Level B: 1500V/1500Ax Level C: 500V/500APass/fail criteria (all shall be verified):x The connector shall comply with EN2591-101 (visual inspection).x The connector shall comply with Requirement #4.2 - Housing (shell) electrical continuity with a measured value after the test of less than 5% above i
45、nitial value.x The connector shall comply with Requirement #4.3 - Insulation resistance.Rationale: The purpose of this test is to assess the dielectric strength of the connector layout. Recent large commercial aircraft use composite materials in the primary structure instead of metal. It changes the
46、 waveform and increases the energy of lightning strikes that aircraft components have to cope with. As the EN2997 was not up-to-date concerning these new lightning waveforms and levels, this requirement was added.-INFORMATION-Information #4.1 - Communication type:This family of connectors is meant t
47、o be used for low level power, analog and digital communications.Information #4.2 - Grounding spring system:The use of a grounding spring system (as specified in EN2297) is recommended to achieve shielding requirement ( 5 P SAE INTERNATIONAL ARD6888 Page 10 of 135. TEMPERATURE REQUIREMENTSRequiremen
48、t #5.1 - Minimum operating temperature:The connector shall be able to operate at the minimum temperature of -65 C.Rationale: Consistent with connector EN2997, qualified on propulsion systems. Requirement #5.2 - Maximum operating temperature:Depending on the model, the connector shall be able to operate at the maximum continuous temperature of: x Level A: 125 Cx Level B: 200 C.Rationale: Two levels specified. O
