1、BRITISH STANDARD AEROSPACE SERIES BSG240:1988 Specification for Pressure transducers for use on aircraft UDC 629.7.054:531.787BSG240:1988 This BritishStandard, having been prepared under the directionof the Aerospace Standards Committee, was published under the authorityofthe Board ofBSIandcomes int
2、oeffecton 29February1988 BSI12-1999 The following BSI references relate to the work on this standard: Committee reference ACE/30 Draft for comment87/78805 DC ISBN 0 580 16294 X Committees responsible for this British Standard Civil Aviation Authority (Airworthiness Division) GAMBICA (BEAMA Ltd.) Min
3、istry of Defence Society of British Aerospace Companies Limited Amendments issued since publication Amd. No. Date of issue CommentsBSG240:1988 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Definitions 1 3 Information to be supplied in the individual tr
4、ansducer specification 1 4 Classification 1 5 Construction 1 6 Output signal 2 7 Electrical supplies 2 8 Performance 2 9 Type tests 4 10 Production tests 5 Table 1 Limits of long-term drift 3 Publications referred to Inside back coverBSG240:1988 ii BSI 12-1999 Foreword This BritishStandard, having b
5、een prepared under the direction of the Aerospace Standards Committee, specifies requirements for pressure transducers for use in aircraft pressure systems. The standard embraces gauge, absolute and differential pressure units. Pressure transducers produced in accordance with this standard have to b
6、e compatible with individual aircraft pressure systems specified by the aircraft manufacturer or the aircraft operator. For each application, the transducer manufacturer produces an individual transducer specification which is called up in the appropriate clauses of this standard. A British Standard
7、 does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an
8、inside front cover, pagesi andii, pages1 to6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BSG240:1988 BSI 12-1999 1 1 Scope This BritishSta
9、ndard specifies requirements for pressure transducers used in aircraft pressure systems, to convert a fluid pressure into an electrical signal for transmission to aircraft indicators or systems. It is applicable to transducers capable of measuring gauge, absolute or differential pressure, that have
10、an accuracy in the range0.25% to2.0% of full scale output at reference conditions, and are capable of working over the ambient temperature range54 C to+85 C. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Definitions For the purposes of this Br
11、itishStandard the following definitions apply. 2.1 transducer a fluid pressure sensor that provides electrical output signals 2.2 proof pressure of the transducer the maximum pressure at which there is no permanent calibration change or leakage 3 Information to be supplied in the individual transduc
12、er specification For the purposes of compliance with this standard the individual transducer specification shall contain the following information: a) details of pipe connections(see5.5); b) details of materials used in the manufacture of the transducer that are in contact with the pressure fluid(se
13、e5.9); c) output signal characteristics(see6.1); d) characteristics of low voltage d.c. supplies needed to operate the transducer(see7.2); e) output signal error limits in the mounting attitude(see8.5); f) response time(see8.6); g) effect on performance when fluid temperature differs significantly f
14、rom the ambient temperature(see8.8.3); h) initial stabilization time(see8.9.2); i) compass safe distance(see8.11); j) acceleration class(see8.15); k) severity grade for salt mist test, i.e.1or2(see8.16); l) requirements for resistance to fluid contamination(see8.18); m) requirements for electrical i
15、nsulation resistance(see8.19); n) power supply variation, if other than that specified in BS3G100-3(see8.21); o) mounting attitude for the accuracy test(see9.1); p) frequency range for the vibration test(see9.12); q) sampling procedure for quality tests(see10.2). 4 Classification Transducers are cla
16、ssified into three types as follows: a) high accuracy (type HA): high accuracy units for specialized application, e.g.flight test measurement; b) medium accuracy (type MA): medium accuracy units for applications where high accuracy is not required, e.g.flight management systems; b) low accuracy (typ
17、e LA): lower accuracy output for general aircraft applications, e.g.flight deck gauges. 5 Construction 5.1 The proof pressure of the transducer shall be not less than1.5times the rated operating pressure. 5.2 The burst pressure of the pressurized components shall be not less than2.0times the rated o
18、perating pressure of the transducer. 5.3 The burst pressure of the case shall be not less than3.0times the rated operating pressure of the transducer or3bar gauge, whichever is the greater (butsee5.11). 5.4 In vented gauge transducers means shall be provided to vent the pressurized fluid in a safe m
19、anner if the pressurized element ruptures. 5.5 Pipe connections shall be as stated in the individual transducer specification. 5.6 Where more than one pipe connection is used, they shall be positively identified to minimize the risk of incorrect connection. NOTESome applications will require mechani
20、cally non-interchangeable connections as stated in the individual contract or order. 5.7 The case strains caused by mounting and/or pipe connections shall not affect the performance of the transducer as specified in8.1. 5.8 Electrical connections shall be as far removed as possible from the pressure
21、 connector(s) to minimize the risk of contamination by the pressure fluid.BSG240:1988 2 BSI 12-1999 5.9 All materials used in the manufacture of the pressure transducer that are in contact with the pressure fluid shall be stated in the individual transducer specification. 5.10 When tested in accorda
22、nce with BS2011-2.1Pz,pressure transducers containing significant quantities of non-metallic materials shall be shown not to support combustion, nor emit significant quantities of smoke or toxic fumes. 5.11 If the pressure transducer is designed to be installed in a location where it may come into c
23、ontact with flammable vapours, it shall comply with BS3G100-2.3.5. 6 Output signal 6.1 The transducer output signal shall be in one of the following forms: a) resistive potentiometer; b) synchro angle; c) frequency change; d) high level voltage output of0V to5V d.c., or0V to10V d.c., that can be ope
24、rated into the minimum load impedance as stated in the individual transducer specification; e) low level voltage output of at least20mV full range output with10V d.c. excitation, when operating into the minimum load impedance as stated in the individual transducer specification; f) current output of
25、0mA to1mA,0mA to10mA or4mA to20mA; g) digital, with characteristics as stated in the individual transduce specification. 6.2 Short circuit protection shall be included in the output signal circuit for transducers except where the transducer is inherently protected by design, or is of low level volta
26、ge outputsee6.1 e). NOTEThe individual transducer specification should state the maximum value of extraneous voltage produced by the transducer in the form of common mode. It should also state whether or not either of the signal lines can be connected to the appropriate power supply line. 7 Electric
27、al supplies 7.1 The transducer shall be designed to operate from any one of the following: a) 115V single phase a.c.400Hz and supplies derived therefrom; b) 28V d.c.; c) low voltage d.c. 7.2 The characteristics of the electrical supplies given in7.1 a) andb) shall be as specified in BS3G100-3. The c
28、haracteristics of low voltage d.c. supplies shall be as stated in the individual transducer specification. 7.3 The transducer shall be protected against damage caused by incorrect polarity power supply connection. 8 Performance 8.1 Accuracy When tested in accordance with9.1, the transducer output ac
29、curacy, including the errors due to combined effect of hysteresis, repeatability, resolution and non-compliance with the design calibration, shall be within the following tolerance bands: type HA: 0.25% of full scale output; type MA: 1.0% of full scale output; type LA: 2.0% of full scale output. NOT
30、EThe overall transducer accuracy may be calculated by combining the components of error by the root-sum-squared (RSS) method. 8.2 Altitude When tested in accordance with9.2, the transducer output signal shall comply with8.1. 8.3 Overpressure When tested in accordance with9.3, the transducer output s
31、ignal shall comply with8.1. 8.4 Case burst pressure When tested in accordance with9.4, the case shall not leak or burst. 8.5 Mounting attitude When tested in accordance with9.5, the transducer output signal errors shall either not exceed the requirements of8.1 by more than 0.1% of the full scale out
32、put per g 1)or comply with the limits stated in the individual transducer specification. 8.6 Response time When tested in accordance with9.6, the transducer output signal shall achieve63% of the signal corresponding to the step pressure input within the time stated in the individual transducer speci
33、fication. 1) g is the acceleration due to gravity.BSG240:1988 BSI 12-1999 3 8.7 Damping When tested in accordance with9.7, the transducer output signal shall achieve a steady state corresponding to the input within two overshoots. NOTETransducers used with incompressible fluids and subjected to over
34、pressure pulses with high pressure rise rates may require special consideration of their damping characteristics. 8.8 Temperature 8.8.1 When tested in accordance with9.8, the transducer output total error band, due to the combined effects of8.1, plus thermal zero and sensitivity shifts and thermal h
35、ysteresis, over the temperature range54 C to+85 C, shall not exceed: type HA: 0.8% of full scale output; type MA: 1.75% of full scale output; type LA: 3.5% of full scale output. 8.8.2 The transducer shall not be deranged by exposure to temperatures between70 C and+90 C when energized. 8.8.3 Where th
36、e temperature of the pressurized fluid differs significantly from the ambient temperature, the effect on the performance of the transducer shall be as stated in the individual transducer specification. 8.9 Long-term stability 8.9.1 When tested in accordance with9.9, the long-term drift due to cumula
37、tive errors from all internal sources shall not exceed the values given in Table 1 without readjustment for a period of30days. 8.9.2 The time required for initial stabilization of the transducer shall be as stated in the individual transducer specification. Table 1 Limits of long-term drift 8.10 End
38、urance When tested in accordance with9.10, the transducer output signal shall comply with8.1. 8.11 Compass safe distance When tested in accordance with9.11, the transducer compass safe distance shall be as stated in the individual transducer specification. 8.12 Vibration 8.12.1 When tested in accord
39、ance with9.12, the error of the transducer due to vibration, at the g levels of the sinusoidal vibration test, in its most sensitive axis shall not exceed 0.1% of the full range output per g. 8.12.2 At the conclusion of the test, the transducer shall not have suffered damage and the output signal sh
40、all comply with8.1 without adjustment. 8.13 Temperature-pressure When tested in accordance with9.13, the performance of the transducer shall not be impaired. 8.14 Mould growth When tested in accordance with9.14, the transducer shall exhibit no mould growth. 8.15 Acceleration 8.15.1 When tested in ac
41、cordance with9.15, the error of the transducer output signal, due to acceleration up to the maximum test g level, in its most sensitive axis shall not exceed 0.1% of the full range output per g. 8.15.2 At the conclusion of the test, the transducer shall not have suffered damage and the output signal
42、 shall comply with8.1 without adjustment. NOTEThe acceleration class should be stated in the individual transducer specification. 8.16 Salt mist When tested in accordance with9.16, the transducer shall not be damaged by salt mist at the severity rating stated in the individual transducer specificati
43、on. 8.17 Waterproofness When tested in accordance with9.17, the transducer output signal shall comply with8.1 both during and after the test. 8.18 Fluid contamination When tested in accordance with9.18, the transducer shall comply with the requirements for fluid contamination resistance stated in th
44、e individual transducer specification. 8.19 Insulation resistance When tested in accordance with9.19, the insulation resistance of the power supply to case and output to case shall be as stated in the individual transducer specification. Accuracy class Limits of long-term drift:percentage of full-ra
45、nge output Type HA Type MA Type LA % 0.05 0.10 0.25BSG240:1988 4 BSI 12-1999 8.20 Radio interference 8.20.1 When tested in accordance with9.20, the transducer output shall be unaffected by the radiated and conducted interference as specified in BS3G100-4.2. 8.20.2 The radiated and conducted interfer
46、ence exported by the transducer shall be within the limits specified in BS3G100-4.2. 8.21 Effect of power supply variation The transducer output signal shall comply with8.1 under power supply variation as stated in BS3G100-3, or as stated in the individual transducer specification. 9 Type tests 9.1
47、Accuracy test Calibrate the output signal of the transducer at the following reference conditions: a temperature of20 5 C; a pressure of860mbar to1060mbar; a relative humidity of45% to75%. The transducer shall be mounted as stated in the individual transducer specification. NOTEThe method of test wi
48、ll depend upon the transducer output signal (seeclause6). 9.2 Altitude test Calibrate the output signal of the transducer at ambient pressure altitudes between1000ft(1050mbar) and70000ft(44mbar). 9.3 Overpressure test Pressurize the transducer to1.5times the rated operating pressure, and maintain th
49、e pressure for a period of10min. Reduce the pressure to within the operating range and, not more than10min following the application of the test pressure, calibrate the transducer output signal as specifiedin9.1. 9.4 Case burst pressure test Seal any vents and pressurize the case to3.0times the rated operating pressure, or3bar gauge, whichever is the greater. Maintain the pressure for a period of10min and check that the case does not leak or burst. 9.5 Mounting attitude test Mount the transducer in each of three mutually perpendicular planes. At
