1、p . I MILITARY SPEC IF ICATION MIL- A-81621 (AS) 25 February 1969 Accelerometer, Electrical, Linear . ABU-l3/A This specification has been approved by the Naval Air Systems Command, Department of the Navy. 1. SCOPE 1.1 Scope - The equipment covered by this specification shall operate as an accelerat
2、ion sensor and electronic voltge multiplier. 1.2 Classification - The equipment covered by this specifi- cation shall consist of the following items: Type Designation Applicable Paragraph ABU- 13/A 3.5 , 1.3 Associated Equipment - This equipment shall operate with the associated equipment listed in
3、6.8. - 2. APPLICABLE DOCUPENTS 2.1 General - The following documents of the issue in effect on the date of invitation for bids form a part of this specification to the extent specified herein: SPECIFICATIONS Military MIL-C-172 Case, Base, Mounting, and Mounts, Vibration Fox Use With MIL-W-5088 Wirin
4、g; Aircraft, Installation of MIL-E-5400 Electronic Eq*iipment, Aircraft, General Specification Far MIL-T-5422 Testing, Environmental, Aircraft Electronic Equipment MIL-E-17555 Electronic and Electrical Equipment and Associated Repair Electronic Equipment in Aircraft Parts, Preparation for Delivery o
5、f 6=M DOCUMWENT COHTASNS Preproduction and Acceptance for Aircraft MIL-N-18307 Nomenclature .and Nameplates for Aeronautical Electronic Electronic Equipment, Format for and Associated Equipment. Naval Air Systems Command AR- 5 Microelectronic Devices Used in Avionics Equipment, Pro- cedures for Sele
6、ction and Approval of AR- 8 Versatile Avionics Shop Test System, Avionics Systems Compatibility, General Requirements for AR- 9 Versatile Avionics Shop Test System Test Program, General Requirements for AR- 10 Maintainability of Avionics Equipment and Systems, General Requirements for STAN DARDS Mil
7、 it ary MIL-STD-461 Electromagnetic Interference Characteristics, Requirements for Equipment of MIL-STD-462 Electromagnetic Interference Characteristics, Measurement MIL-STD-463 Definitions and Systems of Units, Electromagnetic Inter” MIL-STD-704 Electric Power, Aircraft, Characteristics and Utiliza
8、tion MIL-STD-781 Reliability Tests: Expotential Distribution MIL-STD-785 Requirements for Reliability Program for Systems and MIL-STD-794 FED-STD-595 Federal Standard Colors ference Technology of t Equipments Parts and Equipment, Procedures for Packaging and Packing of PUBLICATIONS Naval Air Systems
9、 Command EI-529 Avionics Installation Instructions for Accelerometer, Electrical, Linear 2.1.1 Availability of Docunients - (i) When requesting specifications, standards, drawings and publications, refer to both title and number. Copies of this specifi- cation and. applicable specifications required
10、 by contractors in connection 2 Licensed by Information Handling Services.- - -. MIL-A-81621 12 = 777770b 0357355 O .- MIL-A-81621 (AS) with specific procurement functions may be obtained upon application to the Commanding Officer, Naval Supply Depot, Code 105, 5801 Tabor Avenue, Philadelphia, Penns
11、ylvania 19120. 3. REQUIREMENTS 3.1 Preproduction - This specification makes provision for . preproduction testing. 3.2 Parts and Materials - In the selection of parts and ma- terials, fulfillment of major design objectives shall be the prime consid- eration. In so doing, the following shall govern:
12、(i) Microelectronic technology shall be considered and microelectronic items shall conform to requirements specified herein. * - (2) Other parts and materials requirements shall conform to Specification MIL-E-5400. (3) Nonrepairable subassemblies, as outlined in Specifi- cation MIL-E-5400, shall be
13、used when practicable. The general size of the subassembly and the amount of circuitry30 be included therein shall be approved by the procuring activity. Nonrepairable subassemblies must be reliable. (See 6.5.) (4) When previously produced models of this equipment did not use nonrepairable subassemb
14、lies, the design shall not be changed to employ nonrepairable assemblies with- out the approval of the procuring activity . 3.2.1 Nonstandard Parts and Materials Approval - Approval for the use of nonstandard parts and materials (including electron tubes, tran- sistors and diodes) other than microel
15、ectronic devices shall be obtained as outlined in Specification MIL-E-5400. Microelectronic devices shall be approved as outlined in AR-5. _- 3.2.2 Microelectronic Modular Assemblies - When used, Microelec- tronic Nodular Assemblies shall meet the requirernents of Specification AR-5. Licensed by Inf
16、ormation Handling Services3.2.3 . Modules - The electronic portions of the equipment shall be functionally modularized in accordance with Specification AR-10. 3.3 Design and Construction - The equipment shall conform with all the applicable requirements of Specification MIL-E-5400 for design, constr
17、uct ion and 3.3.1 cables, shall be two pounds, 3.3.2 workmanship, except as otherwise specified herein. Total Weight - The total weight of the equipment, excluding a minimum consistent with good design and shall not exceed Reliability - The contractor shall conduct a reliability program using MIL-ST
18、D-785 as a guide. has previously produced the equipment, the program previously used may be continued unless otherwise indicated in the contract or order. On a reorder from a supplier who 3.3.2,l Operational Stability - The equipment shall operate with satisfactory performance, continuously or inter
19、mittently for a period of at least 1,000 hours without the necessity for readjustment of any controls which are inaccessible to the operator during normal use. 3.3.2.2 Operating Life - The equipment shall have a total operating life of 8,900 hours with reasonable servicing and replacement of parts.
20、Parts requiring scheduled replacement shall be specified by the contractor. 3.3.2.3 Reliability in Mean Time Between Failure (MTBF) - The equipment, including any Built-in-Test provisions shall have 1,000 hours of mean (operating) time“between failures when tested and accepted as out- lined under th
21、e requirements 4.4.3. 3.3.2.4 Shelf Life - The equipment shall remain serviceable with- out maintenance when kept in storage for five years. life shall not be adversely affected by such storage. Shelf life includes The reliable operating those periods of time in which the unit is (i) On the shelf. (
22、2) During shipping. (3) In an aircraft which 3.3.3 Cabling and Connections - 4 I stored: is in a non-operating status. Licensed by Information Handling ServicesMIL-A-B1621 12 m 7999706 0359757 Li I 3.3.3.1 - Cables and Connectors - The equipment shall provide for the use of cables and connectors in
23、accordance with Specification PIIL-E- 5400. 3.3.3.2 Interconnection Cabling - The equipment shall be capable of satisfactory operation using external wiring in accordance with the appli- cable requirements of Specification MIL-W-5088. The external wiring shall be unshielded, except that a minimum nu
24、mber of the individual wires may be shielded when demonstrated as necessary to meet interference control require- ments and provided the assembly of the cable to its plugs may be easily accomplished. External cables and that portion of the connectors attached to the cables shall not be supplied as p
25、art of the equipment. 3.3.3.3 Receptacle Orientation - Receptacles,mounted on vertical surfaces shall be so oriented that the receptacle keyway is at the bottom of the shell of the receptacle. 3.3.4 Interchangeability - The equipment shall meet the inter- changeability requirements of Specification
26、MIL-E-5400. 3.3.5 Interference Control - The generation of radio interference by the equipment and the vulnerability of the equipment to radio interfer- ence shall meet the requirements OF MIL-STD-461, MIL-STD-462 and MIL-STD- 463. 3.3.6 Provisions for Maintainability - The Maintainability Pro- gram
27、, built-in test featres, construction and packaging, provisions for test points, and other maintainability parameters shall be as specified in Specification AR-10. 3.3.6.1 Cornpatability With VAST - The equipment shall be compatible with the Versati3e Avionic Shop Test System (VAST) and shall meet t
28、he re- quirements of Specification AR-8. Sufficient test points shall be provided, in accordance with AR-8 and AR-10, to allow an end-to-end test and for fault isolation to either the electronic multiplier unit or the sensor. Fault isolation to a level within the electronic multiplier is not a re- q
29、uirement. ihen required by contract, VAST Test Programs shall be fur- nished in accordance with Specification AR-9. If VAST Test Programs exist - 5 - . . t, 9 .* . Licensed by Information Handling Services . . -. . . . . . MIL-A-81621 12 M 9999906 0359756 6 M . - i *- MIL-A-81621 (AS) .for the equip
30、ment, and changes to the equipment are made which will affect the fault diagnosis procedure, changes to the existing test program shall be prepared as part of the equipment changes in accordance with Specification AR-9. 3.3.6.2 Self Test Feature - The self test feature shall provide an indication of
31、 satisfactory operation when installed in the aircraft. 3.3.6.3 Field Maintenance - The equipment requires no field main- tenance, calibrations or adjustments. The unit is not repairable in the field and must be returned to the factory for service. 3.3.7 Nomenclature and Nameplates - Nomenc3ature as
32、signment and nameplate approval for equipment identification shall be in accordance with Specification MIL-N-18307. 3.3.8 Standard Conditions - The following conditions shall be used to establish normal performance characteristics under standard con- ditions and for making laboratory Temperature Alt
33、itude Vibration Humid i ty Input power voltage - I bench tests: Room ambient (25OC f 10C) Normal ground None Room ambient up to 90% relative humid i ty 115 f 1.0 V AC - 3.3.9 Service Conditions - The equipment shall operate satis- factorily under any of the environmental service conditions or reason
34、able combination of these conditions as specified in Specification MIL-E-5400 for Class 2 equipment, except as modified herein: 3.3.9.1 Vibration - The equipment shall operate satisfactorily when subjected to the vibration requirements of Curves I and XI of Speci- fication PIIL-E-5400. 3.3.9.2 Tempe
35、rature - The equipment shall operate satisfactorily 6 Licensed by Information Handling Services*. MIL-A-1621 12 7779906 0359757 B 9 MIL-A-81621 (AS) and meet all performance requirements specified in Specification MIL-E-5400 except that the temperature extremes shall be -54C and +lOOC. 3.3.9.3 Shock
36、 The equipment shall operate satisfactorily and shall not suffer damage after being subjected to the shock requirements of Specification MIL-E-5400 except that the impact G level shall be 25G. 3.3.9.4 Acceleration (Steady Stater - The Accelerometer Electrical Linear must meet all operational require
37、ments when subjected to steady state accelerations up to 6Gs in any direction along any axis. 3.3.9.5 Design Load Factor - When mounted directly to a mounting panel, the article shall be capable of withstanding a continuous load factor of 7Gs caused by aircraft accelerations in both directions along
38、 each of three mutually perpendicular axes. formance of structural yielding shall not occur below 115% of the design load factor. Structural failure shall not occur below 150% of the design load factor. Permanentdegradation in per- 3.3.9.6 Undervoltage Protection - The article shall not be damaged b
39、y voltages below the minimum specified herein and shall automatically resume normal operation when the voltage returns within specified limits. - 3.3.10 Warm-up Time - The time required for the equipment to warm up prior to operation shall be kept to a minimum and shall not ex- ceed two minutes unde
40、r standard conditions and five minutes at extreme service conditions. . 3.3-11 Input Electrical Power - 3.3.11.1 Operating Power - The equipment shall meet all applicable requirements of MIL-STD-704 and shall give specified performance when energized from the following power sources having character
41、istics and limits as defined in MIL-STD-704 and limits as specified below. Tk power required shall not exceed the specified amounts. (1) AC Power (Single Phase) 115VJ Category B, 6 VA. 7 . - .- . Licensed by Information Handling Services- 1 MIL-A-Lb21 12 7777706 0357760 = I . .I. MIL-A-81621 (AS) 3.
42、4 Performance - Unless otherwise specified, values set forth to establish the requirements of satisfactory performance apply to perfor- mance under both standard and extreme service and input power conditions. When reduced performance under the extreme conditions is acceptable, toler- ances or value
43、s setting forth acceptable variations from the performance under the standard conditions will be specified. 3.4.1 Operation - The equipment shall operate as an accelera- tion sensing transducer and analog voltage multiplier which will be mounted on an aircraft framing member without shock mounts. In
44、stalled in the air- craft, its sensitive axis will coincide with the aircraft vertical and its operating range will cover upward accelerations from O to SdGs. 741(V)/A computer provides a signal input to the multiplier which may range from O to 10 volts DC. This input will be referred to as the prim
45、ary input. The primary input may have an 800 Hz ripple of up to 100 mv (RMS) super- imposed on the DC voltage. erometer is a magnetic amplifier. The primary output from the Accelerometer shall be a direct current voltage varying as a function of input accelera- tion and primary input voltage and is
46、the input signal to an integrator in the CP-741(V)/A Weapons Release Computer. Accelerometer shall be a direct current voltage varying as a function of input acceleration. . The CP- The source of the primary output of the Accel- The secondary output from the 3.4.2 Self Test - A self-test mode of ope
47、ration is required to enable system testing or component testing. of operation, simulated accelerations of 1.4, 3.5 and 5.OG units shall be provided individually to the Accelerometer. input is required to physically exercise the acceleration sensing transducer. Also, a self-test reference direct cur
48、rent voltage shall be available from ilhen in the self-test mode The simulated acceleration the Accelerometer. 3.5 Detail Requirements - 3.5.1 Accelerometer, Electrical, Linear ABU-l3/A - The Acceler- . orne t er sh a 1 1 me e t the foil lo wing re qu ireme n t s : 3.5.1.1 Function - The Acceleromet
49、er shall provide the following , :. 8 , Licensed by Information Handling ServicesMIL-A-81621 12 777730b 03577bL b E MIL- A181621 (AS) functions: . (1) A function proportional to the ratio of the normal acceleration of an aircraft to the full-scale acceleration (6G) of the Accelerometer and is used to provide information to a CP-741(V)/A Weapons , Release Computer. (2) A function proportional to the normal acceleration of an aircraft and is used to provide information for a programmed “pull-up“ maneuver 3.5.1.2 Form Factor - The Accelerometer shall be enclosed
