ASTM F2537-06

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:F2537–06
Standard Practice for
Calibration of Linear Displacement Sensor Systems Used to
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Measure Micromotion
This standard is issued under the fixed designation F2537; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.1.3 core, n—central rod that moves in and out of the
sensor.
1.1 This practice covers the procedures for calibration of
linear displacement sensors and their corresponding power
NOTE 1—It is preferable that the sensors prevent the core from exiting
supply, signal conditioner, and data acquisition systems (linear
the sensor housing.
displacement sensor systems) for use in measuring micromo-
2.1.4 data acquisition system, n—system generally consist-
tion. It covers any sensor used to measure displacement that
ing of a terminal block, data acquisition card, and computer
givesanelectricalvoltageoutputthatislinearlyproportionalto
that acquire electrical signals and allows them to be captured
displacement. This includes, but is not limited to, linear
by a computer.
variable differential transformers (LVDTs) and differential
2.1.5 differential variable reluctance transducer (DVRT),
variable reluctance transducers (DVRTs).
n—a linear displacement sensor made of a sensor housing and
1.2 This calibration procedure is used to determine the
a core. The sensor housing contains a primary coil and a
relationship between output of the linear displacement sensor
secondary coil. Core position is detected by measuring the
system and displacement. This relationship is used to convert
coils’ differential reluctance.
readings from the linear displacement sensor system into
2.1.6 linear displacement sensor, n—an electrical sensor
engineering units.
that converts linear displacement to electrical output.
1.3 This calibration procedure is also used to determine the
2.1.7 linear displacement sensor system, n—a system con-
errorofthelineardisplacementsensorsystemovertherangeof
sisting of a linear displacement sensor, power supply, signal
its use.
conditioner, and data acquisition system.
1.4 This standard does not purport to address all of the
2.1.8 linear variable differential transformer (LVDT), n—a
safety concerns, if any, associated with its use. It is the
linear displacement sensor made of a sensor housing and a
responsibility of the user of this standard to establish appro-
core. The sensor housing contains a primary coil and two
priate safety and health practices and determine the applica-
secondary coils. When an ac excitation signal is applied to the
bility of regulatory limitations prior to use.
primary coil, voltages are induced in the secondary coils. The
magnetic core provides the magnetic flux path linking the
2. Terminology
primary and secondary coils. Since the two voltages are of
2.1 Definitions:
opposite polarity, the secondary coils are connected in series
2.1.1 calibrated range, n—distance over which the linear
opposing in the center, or null position. When the core is
displacement sensor system is calibrated.
displaced from the null position, an electromagnetic imbalance
2.1.2 calibration certificate, n—certification that the sensor
occurs. This imbalance generates a differential ac output
meets indicated specifications for its particular grade or model
voltage across the secondary coils, which is linearly propor-
and whose accuracy is traceable to the National Institute of
tional to the direction and magnitude of the displacement.
Standards and Technology or another international standard.
When the core is moved from the null position, the induced
voltage in the secondary coil, toward which the core is moved,
increases while the induced voltage in the opposite secondary
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This practice is under the jurisdiction ofASTM Committee F04 on Medical and
coil decreases.
Surgical Materials and Devices and is the direct responsibility of Subcommittee
2.1.9 null position, n—the core position within the sensor
F04.15 on Material Test Methods.
housing where the sensor voltage output is zero (some sensors
Current edition approved Dec. 1, 2006. Published December 2006. DOI:
10.1520/F2537-06. do not have a null position).
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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F2537–06
2.1.10 offset correction, n—removal of any offset in a cable to the linear range of the sensor. Recommended practice
sensor’s output so that at zero displacement, zero voltage is is to use the linear displacement sensor system only within its
recorded. linear working range.
2.1.11 percen
...