Microstrain

Subminiature Gauging DVRT®

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Subminiature Gauging DVRT®

Overview

Designed specifically for tight spaces, the Subminiature Gauging DVRT® delivers high performance in a small package. A ruby bearing and hardened stainless steel ball guide the spring-loaded tip, providing an exceptionally smooth static and dynamic response and resistance to side load. The Subminiature Gauging DVRT® feature sub-micron resolution, linear analog output, flat dynamic response to kHz levels, and very low temperature coefficients. Extremely lightweight, captive cores are small and rugged. Manufactured using corrosion-resistant alloys, Subminiature Gauging DVRT® are suitable for short term submersion in harsh media such as brake fluid and hot saline. MicroStrain’s desktop consoles and in-line signal conditioners provide the Subminiature Gauging DVRT® with plug and play housing, power, analog output, LCD display, RS-232 output and software. A range of modular positioning attachments and custom strokes are also available.

Sensor Design

Core position is detected by measuring the coils’ differential reluctance using a sine wave excitation and synchronous demodulator. This differential detection method provides a very sensitive measure of core position while cancelling out temperature effects.

The transducers’ coils and Teflon® cables are sealed in vacuum-pumped epoxy, within the stainless-steel case. This provides outstanding environmental resistance. The DVRT® has been successfully employed in harsh applications, including short term immersion in saline and pressurized oil.

Units available for long term immersion, corrosive and high pressure environments can be custom built to meet such requirements

Sub-Miniature Displacement Sensor with Gauging
Applications
  • miniature control elements for automotive and robotic systems
  • process control for production-line monitoring
  • dimensional gauging for quality control applications
  • measuring strain and deflection in materials science and civil structures
  • linear/angular positioning of optical components
  • miniature force, torque, acceleration sensors
  • measuring strain, micromotion and deformation in bone and tissue

  • available with sub-micron resolution and long stroke range
  • operating temperature to 175 °C
  • frequency response up to 20 kHz with DEMOD-DC
  • frequency response up to 8 kHz with DEMOD-DVRT
  • lightweight core will not influence frequency response
  • stainless steel and high-performance polymer design suitable for extremely harsh environments
  • waterproof, suitable for short term submersion in corrosive media such as brake fluid and hot saline
  • frictionless design suitable for high duty-cycle applications
  • easily customized to suit specific applications

Electrical Specifications
Obtained using DEMOD-DVRT® and DVRT® with 800 Hz low pass filter at constant temperature

Linear Stroke Length 4, 8, 24, 38 mm (standard resolution)
6 mm (high resolution)
500 µm or less (nano resolution)
Accuracy ± 1.0 % using straight line
± 0.1 % using polynomial
Sensitivity DEMOD output/sensor range
Signal to noise 4200 to 1 (with filter 3 dB down at 800 Hz, standard resolution), 466 to 1 (unfiltered)
Resolution 1.0 µm for 4 mm stroke
2.0 µm for 8 mm stroke
6.0 µm for 24 mm stroke
9.5 µm for 38 mm stroke
0.6 µm for high resolution version
125 nm for nano resolution version (up to 10 nm resolution is possible with customized sensor range and electronics)
Frequency response 800 Hz standard, 20 KHz optional
Temperature coefficient offset 0.002% / ˚C (typical span 0.030% / ˚C (typical)
Hysteresis ± 1 micron
Repeatability ± 1 micron

Mechanical Specifications

Overall body length 30.5 mm for 4 mm stroke
50.5 mm for 8 mm stroke
127 mm for 24 mm stroke
183 mm for 38 mm stroke
50.5 mm for high res version
50.5 mm for nano version
Outside diameter 6.0 mm (smooth body)8.0 mm for 38 mm stroke
Spring stiffness 0.2 N/mm (1 lb/in)
Bearing material sapphire and stainless steel
Standard core tip 4.76 mm stainless steel ball
Housing material 400 stainless steel; smooth body or 3/8-24 UNF thread; 38 mm stroke has 7/16-20 UNF thread
Attachment method threaded body
Leadouts 45 cm multistrand, shielded, stainless steel reinforced teflon insulated cable
Connector keyed 4 pin Lemo, polyolefin relief
Operating temperature -55 to 175 ˚C
Core material stainless steel
Cable diameter 0.070 “

Contact us for information on custom designs suitable for immersion, corrosive and high pressure environments.
Gauging (with Internal Spring) Displacement Starter Kit

8 millimeter stroke DC input/ DC output Subminiature Gauging DVRT Starter Kit

SG-DVRT-8-SK1
Includes (1) SG-DVRT-8, (1) DEMOD-DC

Online Price: $790.00
Part Number: 6107-0131

OEM volume pricing available for embedded applications.