AIR FORCE MIL-PRF-32144 REV B-2012 CLOCK AIRCRAFT ELECTRONIC《电子航空时钟》.pdf

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1、AMSC N/A FSC 6645 DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. MIL-PRF-32144B 12 March 2012 SUPERSEDING MIL-PRF-32144A 18 April 2007 PERFORMANCE SPECIFICATION CLOCK, AIRCRAFT, ELECTRONIC INCH-POUND Comments, suggestions, or questions on this document should be ad

2、dressed to Oklahoma City Air Logistics Center/ENSDAA, 3001 Staff Drive, Suite 1AB81A, Tinker AFB, OK 73145 or emailed to af71tinker.af.mil. Since contact information can change, you may want to verify the currency of this address information using the ASSIST Online database at https:/assist.daps.dla

3、.mil. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-32144B 2 This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification contains the technical and performance

4、requirements for an electronic clock. The electronic clock is intended for use in military aircraft, which may be at a fixed military base, deployed to austere forward operating locations, or naval vessels afloat. This specification provides for first article testing described herein. 2. APPLICABLE

5、DOCUMENTS 2.1 General. The documents listed in this section are specified in sections 3, 4, or 5 of this specification. This section does not include documents cited in other sections of this specification or recommended for additional information or as examples. While every effort has been made to

6、ensure the completeness of these lists, document users are cautioned that they must meet all specified requirements of documents cited in sections 3, 4, or 5 of this specification, whether or not they are listed. 2.2 Government documents. 2.2.1 Specifications, standards, and handbooks. The following

7、 specifications, standards and handbooks form a part of this document to the extent specified herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract. INTERNATIONAL STANDARDIZATION AGREEMENTS STANAG-3643 - Coating Reflection Reducing for Glas

8、s Elements Used in Aircrew Station Displays FEDERAL STANDARDS FED-STD-595/37038 - Black, Flat or Lusterless DEPARTMENT OF DEFENSE SPECIFICATIONS MIL-DTL-7788 - Panels, Information, Integrally Illuminated MIL-L-85762 - Lighting, Aircraft, Interior, Night Vision Imaging System (NVIS) Compatible DEPART

9、MENT OF DEFENSE STANDARDS MIL-STD-130 - Identification Marking of U.S. Military Property MIL-STD-461 - Requirements for the Control of Electromagnetic Interference Characteristics of Subsystems and Equipment Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IH

10、S-,-,-MIL-PRF-32144B 3 MIL-STD-704 - Aircraft Electric Power Characteristics MIL-STD-810 - Environmental Engineering Considerations and Laboratory Tests MIL-STD-1472 - Human Engineering DEPARTMENT OF DEFENSE HANDBOOKS MIL-HDBK-454 - General Guidelines for Electronic Equipment MIL-HDBK-831 - Preparat

11、ion of Test Reports (Copies of these documents are available online at http:/assist.daps.dla.mil/quicksearch/ or from the Standardization Document Order Desk, 700 Robbins Avenue, Building 4D, Philadelphia, PA 19111-5094.) 2.4 Order of Precedence. Unless otherwise noted herein or in the contract, in

12、the event of a conflict between the text of this document and the references cited herein, the text of this document takes precedence. Nothing in this document, however, supersedes applicable laws and regulations unless a specific exemption has been obtained. 3. REQUIREMENTS 3.1 First article. Three

13、 (3) samples shall be subjected to first article inspection (see 4.3) when quantity is not specified in the contract or purchase order. 3.2 Materials. 3.2.1 Nonmagnetic materials. Nonmagnetic parts shall be used, except when magnetic parts and ferrous materials are essential. 3.2.2 Toxic and corrosi

14、ve fumes. Materials installed in the electronic clock and under the service conditions specified herein, shall have no adverse effect on the health of personnel when used as intended. This shall include any fungicidal agents that are used. 3.2.3 Protective treatment. Materials that are used in the c

15、onstruction of the electronic clock which are subject to deterioration and corrosion when exposed to climatic and environmental conditions during service usage shall be protected against any such deterioration in a manner that will in no way prevent compliance with the requirements specified herein.

16、 Protective coatings that will crack, chip, or scale during extremes of climatic or environmental conditions shall not be used. 3.2.4 Fungus proof materials. Materials that are nutrients for fungus shall not be used unless no other material can be used for that application. When used and not hermeti

17、cally sealed, they shall be treated with a fungicidal agent acceptable to the procuring activity. However, if they are used in a hermetically sealed enclosure, fungicidal treatment will not be necessary. Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-

18、,-MIL-PRF-32144B 4 3.2.5 Metals. Metals shall be of the corrosion resistant type, unless protected to resist corrosion during normal service life. 3.2.5.1 Dissimilar metals. Dissimilar metals are defined in Guideline 16 of MIL-HDBK-454. Unless suitably protected against electrolytic corrosion by mea

19、ns of protective coating or hermetic sealing, intimate contact of dissimilar metals shall be avoided. 3.2.6 Protection of ferrous materials. Ferrous materials contained within hermetically sealed enclosures shall be considered suitably protected from corrosion. 3.3 Design and construction. 3.3.1 Cas

20、e. The size and configuration of the case shall be as shown in FIGURE 1 of this specification. The case shall consist of a body and a front panel. The case shall withstand normal shipping, handling and installation procedures. Mounting screws with normal torque applications of 12 inch-pounds shall n

21、ot crush the case. 3.3.1.1 Case finish. The case shall be uniform in texture, and shall have a smooth surface with a durable lusterless black color No. 37038 in accordance with FED-STD-595. The finish shall not present evidence of breakdown during or after testing. Trademarks, company names, or othe

22、r markings not related to the panel function shall not be displayed on the panel face. 3.3.2 Front glass. The front glass shall be flat and free from discolorations, scratches, or other flaws, which may interfere with reading of the Liquid Crystal Display (LCD) of the clock. The viewing distance for

23、 detecting discolorations, scratches, or other flaws shall be 18 inches. All reflecting glass surfaces shall be provided with a reflection-reducing coating conforming to STANAG-3643. In addition, the following reflectance tolerances shall apply in TABLE I: Provided by IHSNot for ResaleNo reproductio

24、n or networking permitted without license from IHS-,-,-MIL-PRF-32144B 5 TABLE I. Reflectance tolerances. 3.3.3 Touch temperature. The maximum stabilized surface temperature of the electronic clock front panel and controls shall not exceed 49C with a cockpit temperature of 26C. 3.3.4 Thermal design.

25、The clock shall be designed to operate throughout the temperature range of 3.4.1 without requiring forced air or liquid cooling. 3.3.4.1 Active visual signals. A heating system for the LCD shall be incorporated in the clock to permit operation down to -40C. The heating methodology shall be compatibl

26、e with the transflection techniques and shall contain an automatic temperature control. 3.3.5 Display lighting. The transmission of illumination through the LCD and cover glass of integrally lighted clocks shall be Night Vision Imaging System (NVIS) compatible in accordance with the lighting charact

27、eristics described below: The center of emission shall be u = 0.088, v = 0.543 and within a radius of 0.037 on the 1976 CIE diagram at 0.1 foot-lamberts (fL). The NVIS Radiance (NR) shall not be greater than 1.7X10-10 when scaled to 0.5 fL. NR is defined as the integral of the curve generated by mul

28、tiplying the spectral radiance of the light source by the relative response curve of the NVIS. In addition the average intensity of the display at 4.50 0.01 VAC shall be 1.0 0.5 fL with no measurement less than 0.5 or greater than 1.5. The clock shall meet the NVIS Quality Assurance provisions of MI

29、L-L-85762 identified in Section 4. 3.3.5.1 Redundant lighting. The clock lighting circuit shall employ redundant lighting. Redundant lighting shall meet the requirements in paragraph 3.3.5 above. 3.3.6 Electrical connector. The electrical connector shall be located as shown in FIGURE1 of this specif

30、ication. The connector used shall be MS27466T9B35P; for guidance, refer to MIL-HDBK-454 Guideline 10. The wiring shall conform to FIGURE 2 of this specification. 3.3.6.1 Safety ground. A wire of minimum length connected internally to the equipment chassis shall be provided at pin number five on the

31、power connector. No circuit shall be allowed to utilize this wire as its return. 3.3.7 Clock system. The solid state electronic clock shall contain: (1) LCD as shown in FIGURE 1; (2) Electronic circuitry to keep track of time in the clock and elapsed time modes; (3) A six digit twenty-four hour nume

32、ric display for hours, minutes, and seconds; (4) A sweep Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-MIL-PRF-32144B 6 second indication. The clock shall meet the following criteria: a. Self test: The clock shall have an automatic self-test featur

33、e which shall illuminate all segments for the first five (5) seconds of display time after 28 VDC power is applied. b. Luminance control: The clock lighting shall operate from the aircraft instrument luminance control. At low levels of luminance, individual segments shall not drop out of view. c. Co

34、ntrast: The display shall be clearly readable under the normal ambient lighting conditions found in airborne cockpits. The perceived luminance (Lp) shall be at least equal to the quantity below across the entire possible ambient light spectrum of 10-4 to 106 fL. d. Contrast performance of the displa

35、y shall be computed when irradiated with a 10,000 foot-candle source measured at the face of the display. Contrast is defined as follows: C = (L2 - L1) / L1 Where C = Contrast L1 = Background Luminance L2 = Display Segment Luminance The clock shall meet the contrast requirements of TABLE II. Display

36、 segment luminance shall be the average of at least three (3) spot measurements equally spaced from each other including one at each end of the segment and at the center of the segment. Lp 3.87L1 (0.926) + 0.05 Where Lp = L2 - L1 Provided by IHSNot for ResaleNo reproduction or networking permitted w

37、ithout license from IHS-,-,-MIL-PRF-32144B 7 TABLE II. Contrast requirements for liquid crystal display. e. Display uniformity: The clock shall utilize a dichroic liquid crystal display with white segments on black background. The display shall conform to FIGURE 1 of this specification. The numerals

38、 and segments shall at all times appear to be uniform in size and color. The apparent size of the segments or numerals shall not appear to change over the entire intensity range. The average luminance of each segment shall be determined by taking a minimum of three spot measurements, one at the cent

39、er of the segment and one at each end of the segment. The maximum and minimum spot luminance within the segment shall be limited such that the most illuminated spot shall be not more than twice the brightness of the least illuminated spot. This shall be tested with the lighting voltage of 4.50 0.01

40、VAC. The luminance variation between each segment of each numeral shall not be greater than 1.3 nor less than 0.7 times the average luminance of all segments in the numeral when measured at 4.50 0.01 VAC. Groups of 5 seconds pointers shall be treated as a single numeral or character. The luminance v

41、ariation between each numeral of the display shall not be greater than 1.2 times or less than 0.8 times the average luminance of all numerals in the display when measured at 4.50 0.01 VAC. Groups of 5 seconds pointers shall be treated as a single numeral or character. f. The individually lighted seg

42、ments shall not reduce their apparent length when the luminance is reduced to night level conditions. g. All external transparent reflection surfaces of the segmented readout display shall be provided with a reflection reducing coating meeting the requirements of paragraph 3.3.2. h. The digits shall

43、 be sharp and clearly readable in all ambient conditions. There shall be a minimum viewing cone of 60 (viewing cone is defined as a 30 angle from a center-line normal to the LCD). The digit sizes shall be per Provided by IHSNot for ResaleNo reproduction or networking permitted without license from I

44、HS-,-,-MIL-PRF-32144B 8 TABLE III, and shall be of the seven-segment format. With the 10,000 foot-candle light source positioned in accordance with FIGURE 4 of MIL-DTL-7788 normal to the display face, the display shall be clearly readable. Note: Clearly readable means anywhere in the viewing cone, a

45、t a distance of 36 inches, the correct time can be read by the operator within 3 seconds. i. Solar radiation shall not degrade the LCD function during normal operational use. j. The display shall not operate without the 28 VDC aircraft power applied. TABLE III. Dimensions for liquid crystal display.

46、 3.3.8 Clock controls. All clock controls and select functions shall be clearly labeled with the letters “SEL“ for select, and “CTRL“ for control, and shall be visible in all operating conditions. Labels shall be in accordance with MIL-STD-1472. The buttons shall be designed to allow easy use by a c

47、rewmember wearing flight gloves. A positive indication of control activation shall be provided, (e.g., snap feel or audible click). The push button surface should be normally concave (intended) to fit the finger. When this is impractical, the surface shall provide a high degree of frictional resista

48、nce to prevent slipping. The button dimensions, resistance, displacement, and separation shall conform to FIGURE 12 of MIL-STD-1472. The buttons shall be located on the lower portion of the clock face as shown in FIGURE 1. 3.3.8.1 Mode selection. The display shall have two modes, one for clock time

49、and one for elapsed time. Depressing the SEL button momentarily shall change from clock mode to elapsed time mode, and back again. The display shall indicate which mode the clock is in at any time by showing a “C“ when in clock time and “ET“ when in elapsed time mode. When power is first applied, the clock shall display the clock time mode. 3.3.8.2 Time set controls. To set