1.1 本规程概述了用于岩土工程目的的位移传感器及其读数系统的校准/验证程序。它涵盖了用于测量位移的任何传感器，该传感器提供与位移成线性比例的电输出。这包括线性可变位移换能器（LVDT）、线性位移换能器（LDT）和线性应变换能器（LST）。 1.2 该校准/验证程序用于确定传感器及其读出系统的输出和长度变化之间的关系。这种关系用于将传感器读出系统的读数转换为工程单位。 1.3 该校准/验证程序还用于确定变送器及其读出系统在其使用范围内的准确性，以与制造商的仪器规范以及仪器对特定应用的适用性进行比较。 1.4 单位-- 括号中以国际单位制或英寸磅单位表示的数值应单独视为标准。每个系统中规定的值可能不是完全相等的；因此，每个系统应独立使用。两个系统的组合值可能导致不符合标准。 1.5 所有观测值和计算值应符合实践中制定的有效数字和四舍五入指南 D6026 除非被本标准取代。 1.5.1 本标准中用于规定如何收集、记录或计算数据的程序被视为行业标准。此外，它们代表了通常应保留的有效数字。所使用的程序不考虑材料变化、获取数据的目的、特殊目的研究或对用户目标的任何考虑；通常的做法是增加或减少报告数据的有效位数以与这些考虑相称。考虑工程设计分析方法中使用的有效数字超出了本标准的范围。 1.6 此实践提供了一套用于执行一个或多个特定操作的说明。这一标准不能取代教育或经验，应与专业判断结合使用。并非此做法的所有方面都适用于所有情况。本ASTM标准并不代表或取代必须判断给定专业服务是否充分的护理标准，也不应在不考虑项目许多独特方面的情况下应用本文件。本文件标题中的“标准”一词仅表示该文件已通过ASTM共识程序批准。 1.7 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.8 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 5.1 位移传感器在测量试样尺寸变化的岩土工程应用中发挥着重要作用。 5.2 位移传感器必须经过校准/验证才能在实验室中使用，以确保传感器的电气输出可靠地转换为工程单位。 5.3 应在首次使用前、此后至少每年、在使用传感器的电子配置发生任何变化后、在使用换能器的测试条件发生与上次校准/验证期间的条件不同的任何重大变化后，对位移换能器进行校准/验证，以及在换能器上可能影响其响应的任何物理动作之后。 5.4 位移换能器通常具有工作范围，在该工作范围内电压输出与换能器的位移成线性比例。此程序适用于传感器的线性范围。建议的做法是仅在其线性工作范围内使用位移传感器。 注1: 实践中的验证 E2309/E2309米 不应与校准混淆

1.1 This practice outlines the procedure for calibration/verification of displacement transducers and their readout systems for geotechnical purposes. It covers any transducer used to measure displacement, which gives an electrical output that is linearly proportional to displacement. This includes linear variable displacement transducers (LVDTs), linear displacement transducers (LDTs) and linear strain transducers (LSTs). 1.2 This calibration/verification procedure is used to determine the relationship between output of the transducer and its readout system and change in length. This relationship is used to convert readings from the transducer readout system into engineering units. 1.3 This calibration/verification procedure also is used to determine the accuracy of the transducer and its readout system over the range of its use to compare with the manufacturer’s specifications for the instrument and the suitability of the instrument for a specific application. 1.4 Units— The values stated in either SI units or inch-pound units given in brackets are to be regarded separately as the standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combination values from the two systems may result in non-conformance with standard. 1.5 All observed and calculated values shall conform to the guidelines for significant digits and rounding established in Practice D6026 unless superseded by this standard. 1.5.1 The procedures used to specify how data are collected, recorded or calculated in this standard are regarded as the industry standard. In addition they are representative of the significant digits that generally should be retained. The procedures used do not consider material variation, purpose for obtaining the data, special purpose studies, or any consideration for the user’s objectives; it is common practice to increase or reduce significant digits of reported data to be commensurate with these considerations. It is beyond the scope of this standard to consider significant digits used in analytical methods for engineering design. 1.6 This practice offers a set of instructions for performing one or more specific operations. This standard cannot replace education or experience and should be used in conjunction with professional judgment. Not all aspects of this practice may be applicable in all circumstances. This ASTM standard is not intended to represent or replace the standard of care by which the adequacy of a given professional service must be judged, nor should this document be applied without consideration of a project’s many unique aspects. The word “standard” in the title of this document means only that the document has been approved through the ASTM consensus process. 1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.8 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 5.1 The displacement transducer plays an important role in geotechnical applications to measure change in dimensions of specimens. 5.2 The displacement transducer must be calibrated/verified for use in the laboratory to ensure reliable conversions of the sensor's electrical output to engineering units. 5.3 The displacement transducer should be calibrated/verified before initial use, at least annually thereafter, after any change in the electronic configuration that employs the sensor, after any significant change in test conditions using the transducer that differ from conditions during the last calibration/verification, and after any physical action on the transducer that might affect its response. 5.4 Displacement transducer generally has a working range within which voltage output is linearly proportional to displacement of the transducer. This procedure is applicable to the linear range of the transducer. Recommended practice is to use the displacement transducer only within its linear working range. Note 1: Verification as in Practices E2309/E2309M should not be confused with calibration