1、BRITISH STANDARD BS 7119:1989 ISO 8042:1988 Specification for Shock and vibration measurements: characteristics to be specified for seismic pick-ups ISO title: Shock and vibration measurements Characteristics to be specified for seismic pick-ups UDC 534.647.004.1:681.892.004.1BS7119:1989 This Britis
2、h Standard, having been prepared under the directionof the General Mechanical Engineering Standards Policy Committee, waspublished under the authorityof the Board of BSIandcomes into effect on 29 September1989 BSI 11-1999 The following BSI references relate to the work on this standard: Committee re
3、ference GME/21 Draft for comment 86/75452 DC ISBN 0 580 17386 0 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the General Mechanical Engineering Standards Policy Committee (GME/-) to Technical Committee GME/21, upon which the following bod
4、ies were represented: British Maritime Technology British Steel Corporation Electricity Supply Industry in England and Wales Institute of Sound and Vibration Research Institution of Mechanical Engineers Lloyds Register of Shipping Ministry of Defence Motor Industry Research Association Power Generat
5、ion Association (BEAMA Ltd.) Society of British Aerospace Companies Limited Society of Environmental Engineers The following bodies were also represented in the drafting of the standard, through subcommittees and panels: British Coal Corporation Electronic Components Industry Federation Health and S
6、afety Executive Amendments issued since publication Amd. No. Date of issue CommentsBS7119:1989 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 1 2 References 1 3 Definitions 1 4 General information 1 5 Characteristics 2 6 En
7、vironmental effects 3 Table Appropriate units for measured quantities 3 Publications referred to Inside back coverBS7119:1989 ii BSI 11-1999 National foreword This British Standard has been prepared under the direction of the General Mechanical Engineering Standards Policy Committee. It is identical
8、 with ISO8042:1988 “Shock and vibration measurements Characteristics to be specified for seismic pick-ups”, which was prepared by Technical Committee ISO/TC108 of the International Organization for Standardization (ISO), and in the development of which the United Kingdom played an active part. Termi
9、nology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the following. The c
10、omma has been used as the decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear referring to this standard they should be read as “British Standard”. The Technical Committee has review
11、ed the provisions of ISO2041, to which reference is made in the text, and has decided that they are acceptable for use in conjunction with this standard. A related British Standard to ISO2041 is BS3015:1976 “Glossary of terms relating to mechanical vibration and shock”. A British Standard does not p
12、urport 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. Cross-references International Standard Corresponding British Standard
13、 ISO 5347:1987 BS 6955:1988 Calibration of vibration and shock pick-ups (Identical) ISO 5348:1987 BS 7129:1989 Mechanical vibration and shock: mechanical mounting of accelerometers (Identical) Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4,
14、 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.BS7119:1989 BSI 11-1999 1 1 Scope and field of application This International Standard lays do
15、wn rules for the presentation of important characteristics for electro-mechanical shock and vibration pick-ups (seismic pick-ups), the electrical outputs of which are known functions of the uniaxial, multiaxial or angular accelerations, velocities or displacements of objects the motions of which are
16、 being measured. It is intended as a guide to instrument manufacturers for indicating characteristics of their pick-ups and as a help to users in selecting a particular type of pick-up or preparing performance specifications. The intention is to ensure that the user receives an adequate description
17、of the characteristics of any particular pick-up. Throughout this International Standard, shock and vibration pick-ups will be referred to simply as “pick-ups”. 2 References ISO 2041, Vibration and shock Vocabulary. ISO 5348, Mechanical vibration, and shock Mechanical mounting of accelerometers. ISO
18、 5347, Methods for the calibration of vibration and shock pick-ups. 3 Definitions For the purposes of this International Standard, the definitions given in ISO2041 and ISO5347 apply. 4 General information 4.1 General The information specified in4.2 to4.16 may be helpful to the user of pick-ups. It i
19、s recommended that the manufacturer provide this information, in full or in part, in his literature and in any descriptive leaflet supplied with the pick-up. 4.2 Type The manufacturer shall state whether the output of the pick-up is substantially proportional to the displacement, velocity or acceler
20、ation of the vibration or shock input. 4.3 Type of motion The manufacturer shall indicate the nature of the motion to which the pick-up will respond, such as uniaxial; multiaxial; angular. 4.4 Sensing element The type of sensing element shall be indicated, for example, as follows: strain-sensitive r
21、esistance wire, bonded or unbonded; resistive potentiometer; variable capacitance; variable inductance; differential transformer; electromagnetic element; piezoelectric element; electronic tube; photoelectric element; electrokinetic element; piezoresistive element; optical element; magnetostrictive.
22、 4.5 Orientation The suitability of the pick-up for use in vertical, horizontal and inverted mounting positions shall be stated. 4.6 Indication of sensitive direction The sensitive direction of the pick-up, called the axis of measurement, shall be indicated, for example by an arrow. If practical, th
23、e positive direction shall be marked or indicated by the orientation of an arrow and the polarity of output for motion in the positive direction shall be described. 4.7 Overall dimensions Overall outline dimensions of the pick-up shall be given in a diagram. 4.8 Material The material of the mounting
24、 base and surfaces exposed to its operational environment shall be stated. 4.9 Attachment It shall be indicated whether the pick-up a) is screwed, clamped, cemented, etc. to the vibrating surface, or whether it b) may be hand-held, as for a probe type. 4.10 Mounting The method of mounting and the lo
25、cation and size of the mounting holes or the studs in the pick-up shall be given. If screws are used to mount the pick-up, the mounting torque shall be recommended. For all factors relating to mounting, see ISO5348.BS7119:1989 2 BSI 11-1999 4.11 Mass and moment of inertia For uniaxial and multiaxial
26、 pick-ups, the mass and centre of gravity of the pick-up should be given; for angular vibration pick-ups, the moment of inertia, referred to the axis of measurement, should be given. If a pick-up is normally used above its natural frequency, the magnitude of the seismic mass shall be specified. 4.12
27、 Position of sensing element If applicable, the location of the centre of gravity of the sensing element shall be given. (This information is needed in the calibration of accelerometers on a centrifuge and in other applications where there may be a spatial gradient or a combination of uniaxial and r
28、otational motion in the quantity being measured.) 4.13 Connections If electrical connections between the pick-up and auxiliary equipment are required for its use, their type (e.g. low noise), length, mass, shielding, connection to case and type of connectors (if any) shall be stated, together with t
29、he recommended method of fixing the cable assembly to avoid unwanted dynamic effects on the pick-up. 4.14 Energy source The manufacturer shall state whether the pick-up is self-generating and, if not, shall indicate the nature of the energizing or polarizing source. 4.15 Nature of output The nature
30、of the output of the pick-up shall be indicated. Various indications may be useful, for example, as follows: a) that the output is a voltage or, furthermore, that it is a modulated carrier voltage or a frequency-modulated voltage; or b) that the output is linearly, logarithmically or otherwise relat
31、ed to the input vibration. 4.16 Auxiliary equipment The manufacturer shall state the type of or certain relevant characteristics of any required auxiliary equipment, for example, as follows: a charge amplifier to convert the charge output of a piezoelectric pick-up to a low impedance voltage; a spec
32、ified input impedance this may be required for auxiliary equipment such as an impedance convertor; a demodulator, used to eliminate the carrier frequency; a filter, used to remove undesired signals; a biasing voltage or bridge network, used to obtain zero output when a zero value of the motional fun
33、ction is applied; certain non-linear devices, used to correct for non-linearity of the output signal; integrating and differentiating circuits, their frequency range being stated. A wiring diagram shall be given to enable the pick-up to be correctly connected to the auxiliary equipment. 5 Characteri
34、stics 5.1 Measurement range The maximum and minimum measurement range for reliable indication shall be given in terms of acceleration, velocity and/or displacement. The maximum range may be limited by maximum motion within a specified accuracy which could lead to loss of linearity, motions exceeding
35、 the setting of stops, motions exceeding the ability of a pick-up mechanism to follow faithfully, and motions which would damage a pick-up. The minimum range may be limited by the minimum resolving power of a pick-up, sticking where rubbing friction is present, thermal or electrical noise interferen
36、ce, or reduced accuracy due to loss of linearity. 5.2 Sensitivity, frequency response Data concerning output versus input for a specified frequency in the operating range shall be given. For pick-ups the output of which is proportional to input, the proportionality factor shall be given in the form
37、of a rated sensitivity. The probable error of sensitivity calibration shall be stated. The effect of frequency on sensitivity may be presented graphically by plotting the sensitivity as a function of frequency. The terminating impedance which applies to this presentation, as well as to other sensiti
38、vity presentations, shall always be specified. In pick-ups requiring an energizing voltage (alternating or direct), a carrier voltage or a biasing voltage, the rated sensitivity shall be either the value obtained when the recommended voltage is applied or the value obtained per volt. The recommended
39、 value of the biasing voltage shall be stated. The relationship of output to input shall be given in compatible units such as r.m.s. voltage or charge in conjunction with r.m.s. velocity, or peak voltage or charge in conjunction with peak velocity, and not as r.m.s. voltage or charge with peak veloc
40、ity. Some of the appropriate units are given in the Table.BS7119:1989 BSI 11-1999 3 Table Appropriate units for measured quantities 5.3 Frequency range In well defined mounting conditions, the operating frequency range over which the pick-up sensitivity does not vary from the rated sensitivity by mo
41、re than a stated percentage shall be given, together with its seismic resonance frequency and any spurious resonance frequencies which affect the output signal. Where applicable, the approximate magnification (Q-factor) shall be stated for each resonance frequency. 5.4 Phase shift, frequency respons
42、e The maximum phase shift or phase angle between an impressed sinusoidal vibration and the resulting sinusoidal output signal, with a specified output termination, shall be given for operation in the recommended frequency range. The phase shift versus frequency may be presented graphically. If the p
43、hase shift is zero, this shall be stated. NOTEThe phase response may be given relative to a known reference. 5.5 Damping In well defined mounting and electrical termination conditions, the damping ratio shall be given. This may be stated in terms of logarithmic decrement or Q-factor. 5.6 Transverse
44、sensitivity The maximum sensitivity to motions transverse to the measurement axis of the pick-up and the frequency at which it is measured shall be given, together with its sensitivity to other kinds of motion which will affect its output, e.g. rotational motion. If the sensitivity to transverse mot
45、ions varies depending on the direction of the motion, the maximum sensitivity, its direction and frequency shall be stated. 5.7 Limits for maximum motion without damage The maximum vibration and shock motion in both sensitive and transverse axes, given in terms of acceleration, velocity and/or displ
46、acement (and, where applicable, its frequency), for reliable operation without damage shall be given. 5.8 Linearity and hysteresis The maximum deviation from a straight line for output versus input over the whole range of the pick-up shall be stated. This deviation may be expressed as a percentage o
47、f the reading or as a percentage of the full scale. 5.9 Electrical impedance The electrical impedance of a pick-up is the ratio of the open circuit voltage to the short-circuit current. Where appropriate, the magnitude and phase angle of this impedance shall be tabulated for several frequencies over
48、 the range of operation, or, alternatively, a plot of these values as a function of frequency shall be included. If applicable, the impedance shall be stated in terms of equivalent values of inductance, resistance and capacitance, as appropriate, which apply over the range of frequencies for which t
49、he pick-up is recommended. 6 Environmental effects 6.1 Temperature and humidity effects The operating temperature and/or humidity range over which the pick-up sensitivity and damping do not vary from their rated values by more than a stated percentage shall be given. The change of these quantities with temperature can be shown graphically. Minimum and maximum storage temperatures and humidity shall be given. The temperature and humidity limits beyond which the pick-up might be damaged shall also be given. The effects an
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