1、Specifications and Tests for Strain Gage PressureTransducersReaffirmed 29 September 1995ISA37.31982 (R1995)Formerly ISAS37.31982 (R1995)STANDARDISA The Instrumentation,Systems, andAutomation Society TMCopyright 1982 by the Instrument Society of America. All rights reserved. Printed in the UnitedStat
2、es of America. No part of this publication may be reproduced, stored in a retrieval system, ortransmitted in any form or by any means (electronic, mechanical, photocopying, recording, orotherwise), without the prior written permission of the publisher.ISA67 Alexander DriveP.O. Box 12277Research Tria
3、ngle Park, North Carolina 27709ISA-37.3-1982 (R1995), Specifications and Tests for Strain Gage Pressure TransducersISBN 0-87664-378-0ISA-S37.3-1982 (R1995) 3PrefaceThis preface, as well as all footnotes and annexes, is included for informational purposes and is not part of ISA-37.3-1982 (R1995).This
4、 standard has been prepared as a part of the service of ISA, the international society for measurement and control, toward a goal of uniformity in the field of instrumentation. To be of real value, this document should not be static but should be subject to periodic review. Toward this end, the Soci
5、ety welcomes all comments and criticisms and asks that they be addressed to the Secretary, Standards and Practices Board; ISA; 67 Alexander Drive; P.O. Box 12277; Research Triangle Park, NC 27709; Telephone: (919) 549-8411; Fax: (919) 549-8288; E-mail: standardsisa.org.The ISA Standards and Practice
6、s Department is aware of the growing need for attention to the metric system of units in general, and the International System of Units (SI) in particular, in the preparation of instrumentation standards, recommended practices, and technical reports. The Department is further aware of the benefits t
7、o USA users of ISA standards of incorporating suitable references to the SI (and the metric system) in their business and professional dealings with other countries. Toward this end, this Department will endeavor to introduce SI and acceptable metric units in all new and revised standards to the gre
8、atest extent possible. The Metric Practice Guide, which has been published by the Institute of Electrical and Electronics Engineers as ANSI/IEEE Std. 268-1992, and future revisions, will be the reference guide for definitions, symbols, abbreviations, and conversion factors.It is the policy of ISA to
9、 encourage and welcome the participation of all concerned individuals and interests in the development of ISA standards, recommended practices, and technical reports. Participation in the ISA standards-making process by an individual in no way constitutes endorsement by the employer of that individu
10、al, of ISA, or of any of the standards which ISA develops.The development of this Standard was initiated as the result of a survey conducted by the Survey Committee on Transducers for Aero-Space Testing (8A-RP37) in December 1960. In addition to the strong need for improved and uniform transducer no
11、menclature and specification terminology, many of the people surveyed also indicated the need for standardization of performance characteristic specifications, test methods, and electrical requirements for certain classes of transducers used in Aero-Space Testing. Accordingly, five subcommittees wer
12、e established initially, each to deal with one of these classes of transducers. Subcommittee 8A-RP37.3 (Subcommittee on Strain Gage Pressure Transducers, “SCOSGAPT“) was organized on May 1, 1961, to prepare a Recommended Practice for strain gage pressure transducers. Six successive drafts were prepa
13、red and submitted for review and comments to a large number of people active in aerospace industries and sciences in which strain gage pressure transducers are used. The final document, ISA-RP37.3 (Guide for Specifications and Tests for Strain Gage Pressure Transducers for Aero-Space Testing), was p
14、ublished by ISA in April 1964. It was revised in 1970 and approved as ANSI Standard MC 6.2 in October 1975.This Standard was prepared under the direction of Paul S. Lederer (Chairman S37.3) by members of SP37 by updating and expanding the previous version of the document and by obtaining extensive r
15、eviews of drafts of the Standard by representatives of transducer users and manufacturers as well as agencies of the U.S. Government. The reviewers were selected from a broad cross-section of all industries and sciences in which transducers are applied for measuring purposes.4 ISA-S37.3-1982 (R1995)
16、This Standard is intended as a guide for technical personnel at user facilities as well as by manufacturers technical and sales personnel whose duties include specifying, calibrating, testing, or showing performance characteristics of potentiometric pressure transducers. By basing users specificatio
17、ns as well as technical advertising and reference literature on this Standard, or by referencing portions thereof, as applicable, a clear understanding of the users needs or of the transducers performance capabilities, and of the methods used for evaluating or proving performance, will be provided.
18、Adhering to the specification outline, terminology and procedures shown will not only result in simple, but also complete specifications; it will also reduce design time, procurement lead time, and labor, as well as material costs. Of major importance will be the reduction of qualification tests res
19、ulting from use of a commonly accepted test procedures and uniform data presentation.The following individuals served on the 1975 SP37.3 Subcommittee:NAME COMPANYP. S. Lederer, Chairman National Bureau of StandardsJ. F. Arbogast Hercules Powder CompanyD. M. Keast Bolt, Beranek and NewmanD. L. Limbac
20、her Aerojet-GeneralH. E. Lockery Baldwin-Lima-HamiltonW. R. Myers Consolidated ElectrodynamicsThe following individuals served on the ISA Committee SP37, who reaffirmed ISA-S37.3 in 1995:NAME COMPANYE. Icayan, Chairman Westinghouse Hanford Co.J. Weiss Electric Power Research InstituteP. Bliss, Decea
21、sed ConsultantM. Brigham The Supply SystemD. Hayes LA Dept. Water e.g., psia for absolute pressure in psi. In the interim it is recommended that for the SI system, the type of pressure be indicated in this manner: “ . . . An absolute pressure of _Pa.“ “ . . . A differential pressure range of_ kPa,“
22、etc.2. For differential pressure transducers, the allowable range of reference pressures shall be listed; e.g., “0 to 1MPa“ or “0 to 100 psi.“4.1.1.2 Measured fluids*The fluids in contact with pressure port(s) shall be listed; e.g., nitric acid, liquid oxygen. Requirements for and limitations on the
23、 isolating element (if used) shall be listed.4.1.1.3 Materials in contact with the measured fluidThe materials in contact with the measured fluid shall be listed.NOTE For differential pressure transducers, materials in both ports must be considered.4.1.1.4 Configuration and dimensionsThe outline dra
24、wing shall show the configuration with dimensions in millimeters (inches). Unless pressure and electrical connections are specified (reference 4.1.1.5 and 4.1.3.4), the outline shall include limiting maximum dimensions for these connections.4.1.1.5 Pressure connectionThe pressure connection(s) shall
25、 be indicated on the outline drawing. For threaded fittings, specify: Applicable Military or Industry standards or nominal size, number of threads per millimeter (threads per inch), thread series, and thread class. For hose tube fitting, specify tube size.4.1.1.6 Mountings and mounting dimensionsUnl
26、ess the pressure connection serves as a mounting, the outline drawing shall indicate the method of mounting with hole size, centers, and other pertinent dimensions in millimeters (inches), including thread specifications for threaded holes, if used.4.1.1.7 Mounting effectsThe maximum mounting force
27、or torque shall be specified if it will tend to affect transducer performance (reference 4.2.28).4.1.1.8 MassThe mass of the transducer shall be specified in grams (ounces).*Defined in ISA-S37.112 ISA-S37.3-1982 (R1995)4.1.1.9 Case sealingIf case sealing is necessary, the mechanism and materials use
28、d for sealing should be described. The same requirement applies to the electrical connector. The resistance of the sealing materials to cleaning solvents and commonly used measured fluids should be stated.4.1.1.10 IdentificationThe following characteristics shall be permanently inscribed on the outs
29、ide of the transducer case or on a suitable nameplate permanently attached to the case.a) Nomenclature of transducer (according to ISA-S37.1, Section 3)b) Name of Manufacturer, (Part number to reflect one controlled configuration), and Serial Numberc) Range* in Pa (psi) and designation of type of pr
30、essure (See 4.1.1.1.)Maximum excitation*d) Identification of Measured and Reference Ports* (for differential pressure transducers)Reference Pressure Range* (for differential pressure transducers)e) Identification of Electrical Connectionsf) Schematic of Electrical Connections g) Nominal Bridge Resis
31、tanceh) Inscription of the following characteristics is optional:1) Sensitivity2) Customer Specification or Part Number, or Both3) Type of Electrical Connector (if applicable)4) Maximum Excitation5) Maximum Reference Pressure6) Maximum and Minimum Operating Temperature4.1.1.11 Maximum and minimum op
32、erating and fluid temperature* The maximum and minimum temperature of fluids or environments that can be applied to the transducer and that will not cause permanent calibration shift shall be listed.4.1.2 Supplemental mechanical design characteristicsListing of the following mechanical design charac
33、teristics is optional.*Defined in ISA-S37.1ISA-S37.3-1982 (R1995) 134.1.2.1 Case material4.1.2.2 Pressure sensing elementa) Diaphragm, flat or corrugatedb) Capsulec) Bellowsd) Straight Tubee) Bourdon Tube, plain, spiral, helical, or twistedf) Liquid-Filled Configuration (Liquid shall be specified.)4
34、.1.2.3 Type of strain gage useda) Metallic; bonded or unbonded, wire or foil, deposited thin film b) Semiconductor; bonded, unbonded, or diffused4.1.2.4 Location of strain gagea) Mounted directly on pressure sensing elementb) Mounted on auxiliary member, and activated by pressure sensing element4.1.
35、2.5 Number of active strain gage elementsa) Oneb) Two-arm Bridgec) Four-arm Bridge4.1.2.6 Dead volume*For non-flush mounted transducers, the dead volume shall be given in cubic millimeters (cubic inches). For differential pressure transducers, the volume of both cavities should be listed.4.1.2.7 Vol
36、ume change due to full scale pressureThe change in volume of the sensing element due to application of full scale pressure shall be given in cubic millimeters (cubic inches).4.1.3 Basic electrical design characteristicsThe following electrical design characteristics shall be listed. They are applica
37、ble at “room conditions“ according to the definition given in ISA-S37.1.4.1.3.1 Excitation *Expressed as “ _ volts dc“ or “ _ volts rms at _ Hz.“ (Preferred values are 5, 10, 20, and 28 volts) or “ _ mA dc“ or “_ mA rms at _ Hz.“*Defined in ISA-S37.114 ISA-S37.3-1982 (R1995)4.1.3.2 Maximum excitatio
38、n *Expressed as “ _ volts dc“ or “ _ volts rms at _ Hz“ or “ _ mA dc“ or “ _ mA rms at _Hz.“4.1.3.3 Input impedance*Expressed as “ _ _ ohms at _ _ Hz.“ If impedance is resistive, indicate this.NOTE Output “open-circuit“ for this measurement.4.1.3.4 Output Impedance*Expressed as “ _ _ohms at _ _ Hz.“
39、 If impedance is resistive, indicate this.NOTE If excitation terminals are “short-circuit“ for this measurement, this should be indicated.4.1.3.5 Load impedance* Performance characteristics values apply only for load impedance values of _ ohms, minimum or _ _ ohms.4.1.3.6 Electrical connections Whet
40、her the electrical termination is by means of a connector or a cable, the pin designations or wire color code shall conform to the following transducer wiring standard promulgated by the Western Regional Strain Gage Committee, as approved September 18, 1957, and revised May 6, 1960.*Defined in ISA-S
41、37.1ISA-S37.3-1982 (R1995) 15NOTES1) The output polarities indicated on the above wiring diagram apply when an increasing absolute pressure is applied to the pressure port (sensing end) of an absolute pressure transducer. For differential and gage pressure transducers, the indicated polarities apply
42、 when the absolute pressure at measurand port is greater than the absolute pressure at the reference pressure port.2) The measurand (pressure) port of differential pressure transducers shall be marked “+“ or optionally “high“ or “meas.,“ while the reference (pressure) port shall be marked “ or optio
43、nally “low“ or “ref.“3) The bridge elements shall be arranged so that functions producing positive output will cause increasing resistance in arms 1 and 3 of the bridge.4) For shielded transducers, pins 5, 7, and 9 shall be shield terminals for 4, 6, and 8 wire systems respectively.5) Position of an
44、y internal compensation network should be indicated.4.1.3.7 Insulation resistance* Expressed as “ _ megohms at _ volts dc between all terminals in parallel and the transducer case, at a temperature of _ _C(F).“4.1.4 Supplemental electrical design characteristicsListing of the following electrical de
45、sign characteristic is optional.4.1.4.1 Shunt calibration resistor Expressed as “ _ ohms for _% of full scale output.“ See 4.3.NOTE The terminals across which this resistor is to be placed shall be specified, if the resistor is used.4.2 Performance characteristicsThe pertinent performance characteri
46、stics of strain gage pressure transducers should be tabulated in the order shown. Unless otherwise specified, they apply at “room conditions“ as defined in ISA-S37.1; Temperature: 25 10C (77 18F); Relative Humidity: 90% maximum; Barometric Pressure: 73 7 cm of Hg (29 3 inches of Hg) and after an ade
47、quate warm-up period (see 4.2.13).Terminology used here is defined in either ISA-S37.1 or 4.3 of this document. An asterisk appears beside the paragraph number of those terms defined in S37.1.4.2.1 Range*Usually expressed as “ _ to _ Pa (psia, psig)“ or “ _ Pa (psid)“ or “zero to _ Pa (psid.)“NOTE E
48、quivalent pressure units in the SI system are expressed in Pascals.*Defined in S37.116 ISA-S37.3-1982 (R1995)1 psi = 6894.8 Pa10kPa = 1.4504 psi4.2.2 End points*Expressed as “ _ _ mV and _ _ mV at _ volts (milliamps) excitation.“4.2.3 Full-scale output *Expressed as “_ _mV per volt (milliamp) excitation into specified load impedance“ or “ _ _mV at _ volts (milliamp) excitation into specified load impedance.“NOTE If 4.2.2 and 4.2.3 are used to specify performance characteristics, the toler
