SEGMENsensor spring-loaded LVDT sensors are designed for continuous contact gauging, surface profiling, and dimensional measurement applications. The internal spring mechanism maintains constant probe contact force against the workpiece, ensuring reliable measurement without manual positioning. Stroke ranges 10–100 mm. AC/DC LVDT output or built-in signal conditioner (4-20mA, 0-10V). CE certified, OEM programs, samples 1–5 pcs in 5–7 days.
A SEGMENsensor spring-loaded LVDT sensor is a linear variable differential transformer with an internal return spring that keeps the probe tip in constant contact with the target surface. It suits continuous contact gauging and surface profiling over 10–100 mm strokes, with AC output or a built-in 4-20 mA / 0-10 V conditioner.
Stroke options are 10, 25, 50 and 100 mm.
Linearity is ±0.1% FS as standard, with a precision version available on request.
Spring contact force is 0.5–1.5 N, adjustable on some models.
The conditioned version runs on 12–30 V DC; operating temperature is -20 to +80 °C.
Housings are 316L stainless steel with an 8 mm gauge body, and qualification samples are 1–5 pcs.
Last updated · SEGMENsensor Engineering Team
Watch: how to choose, mount and wire an LVDT
LVDT Sensor: How to Choose, Mount and Wire It (AC vs DC)Gauging probe, separate core or pen type; AC or DC output; mounting without side load, setting the null point, and wiring to a PLC or a signal conditioner.
LVDT displacement sensors: how to choose one, mount it, and wire it. An LVDT has one primary coil and two secondary coils. A movable core changes how strongly they couple, so the output follows the core position, with no contact and no wear. With the core in the centre, the null point, the two secondary signals cancel. Move the core either way and the output rises, and its sign tells you the direction. There are three main types. Gauging probes have a spring-loaded tip for dimension checks, with ranges from ±0.5 mm to ±5 mm. Separate-core LVDTs, where the core rides on the moving part, cover ±2 to ±100 mm. Pen-type sensors with a built-in conditioner reach ±500 mm. Next, choose the output. An AC LVDT needs an external excitation of 1–10 kHz and a signal conditioner. A DC LVDT has the electronics built in. Supply 10–30 V DC, and read 4–20 mA, 0–10 V, or RS485 Modbus directly. Mounting. Centre the core in the bore so it never rubs the tube, and keep side loads off the probe. Clamp the body on its housing without over-tightening, so the housing is not deformed. For a ± range, set the reference position at the centre: the output reads zero, or 12 mA on a 4–20 mA output. Wiring a DC LVDT: supply + and 0 V, and the signal to the PLC analog input. Use shielded cable and ground the shield at one end only. An AC LVDT connects to a signal conditioner: its excitation output drives the primary, and the two secondaries return to its input. Keep the cable away from motor and drive cables. Before you order, specify the stroke, linearity, output, supply, temperature and connection. Linearity is ±0.25% FS as standard, or ±0.1% FS for high accuracy. SEGMENsensor makes gauging probes, separate-core and pen-type LVDTs, in 303 or 316L stainless steel, rated IP67. SEGMENsensor LVDT sensors. OEM volume supply. Datasheets and quotes at segmensensor.com.
How an LVDT WorksOne-minute animation of the linear variable differential transformer: primary and two secondary coils, the moving core, the null position, and how the size and phase of the difference signal give distance and direction.
What is an LVDT, and how does it measure position? An LVDT has three coils: a primary coil in the middle, and a secondary coil on each side. A movable core slides inside, on a push rod. An AC voltage excites the primary. With the core centred, both secondaries pick up equal voltages, and the difference is zero. When the core moves, one secondary couples more strongly than the other. The size of the difference shows how far the core moved, and its phase shows the direction. Electronics turn this into a DC signal, such as 4–20 mA. The core never touches the coils, so there is no wear. SEGMENsensor LVDT sensors: strokes from ±0.5 mm to ±500 mm. Learn more at segmensensor.com.
What is a Spring-Loaded LVDT Sensor?
A spring-loaded LVDT sensor is a Linear Variable Differential Transformer with an internal return spring that keeps the measurement probe in constant contact with the target surface. Unlike standard LVDT sensors where the core is mechanically coupled to the moving part, a spring-loaded gauging LVDT uses a hardened ruby or carbide probe tip on the extending rod, pressed against the target by spring force. When the target surface moves, the probe follows it precisely, and the LVDT core displacement is converted to a voltage or 4-20mA signal proportional to position. Used for automated gauging, surface measurement, and 100% in-process inspection.
Specifications
Spring-Loaded LVDT Sensor — Full Technical Specifications
Samples 1–5 pcs in 5–7 working days. AC LVDT and DC conditioned versions available. Precision ±0.05% FS and custom probe tip options on request.
Parameter
Specification
Measurement Principle
LVDT (Linear Variable Differential Transformer)
Probe Return
Internal spring (compression)
Stroke Range
10 mm / 25 mm / 50 mm / 100 mm
Linearity
±0.1% FS (standard) / ±0.05% FS (precision)
Output (AC)
±3V AC (primary excitation 5V / 2–10 kHz)
Output (DC, conditioned)
4-20mA / 0-5V / 0-10V / ±10V
Supply Voltage (DC)
12–30V DC (conditioned version)
Resolution
Infinite (analog), limited by signal conditioner
Probe Tip
Hardened Ruby (standard) / Carbide / Ball / Flat
Housing Material
Stainless Steel 316L
Bore Diameter
8 mm (standard gauge body)
Spring Force
0.5–1.5 N (adjustable on some models)
Operating Temperature
-20°C to +80°C
Connector
M12×1 4-pin (DC) / Flying lead (AC)
Samples
Samples 1–5 pcs for qualification; volume per project
Lead Time
Confirmed with the quotation (standard production); samples 1–5 pcs in 5–7 days; custom confirmed at order
Certifications
CE, RoHS
Download the LVDT displacement sensor datasheet (PDF)
Measuring ranges, linearity, output options, core and spring-loaded versions, housing dimensions, connectors, temperature limits and the ordering code. No registration required.
Three operating stages: spring-maintained contact → LVDT core displacement → analog signal output. Infinite resolution, no contact wear on the LVDT core itself.
01
Spring Maintains Probe Contact
An internal compression spring pushes the probe rod outward with 0.5–1.5 N of force. The hardened probe tip (ruby or carbide) maintains constant contact with the target surface. When the part is loaded into the fixture, the probe retracts against the spring force — no manual zeroing required. The spring force is engineered to be strong enough to follow the surface but light enough not to deflect rigid workpieces.
02
LVDT Core Follows Probe Displacement
The probe rod is mechanically linked to the LVDT's ferromagnetic core. As the probe retracts or extends with surface variation, the core moves axially inside the LVDT coil assembly. The LVDT's primary coil is energized with a sinusoidal excitation signal (AC version: external oscillator; DC version: internal oscillator). Two secondary coils produce differential output proportional to core position. The LVDT core has no friction contact — infinite mechanical life.
03
Signal Conditioner Outputs DC or AC
In the AC LVDT version, the differential secondary voltage is fed to an external signal conditioner that demodulates and linearizes it to a DC voltage proportional to displacement. In the DC conditioned version, this electronics is built into the sensor housing — input 12–30V DC, output 4-20mA or 0-10V, directly readable by any PLC analog input. Both versions provide infinite resolution limited only by the noise floor of the signal conditioner electronics.
Applications
Spring-Loaded LVDT Sensor Applications — 8 Industrial Use Cases
From precision gauging fixtures to press monitoring — spring-loaded LVDT sensors are the standard tool for dimensional measurement where contact gauging is required.
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Automated Gauging Fixtures
100% part inspection in machining cells — measure bore depth, step height, flatness. Spring-loaded probe retracts for part load/unload, extends to contact surface automatically.
📐
Surface Profiling Systems
Continuous surface texture and runout measurement on rotating parts. The spring ensures the probe follows surface contour at measurement speeds up to several mm/s without lift-off.
🏗️
Press Tooling Monitoring
Ram displacement and die closure measurement in stamping presses. LVDT output feeds press controller for bottom-dead-center detection and tonnage monitoring.
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Rubber & Plastic Thickness
Continuous thickness gauging on extrusion and calendering lines. Opposed pair of spring-loaded LVDTs measures material thickness from both sides in real time.
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Semiconductor Wafer
Thickness measurement in lapping and polishing equipment. Low spring force variants (0.2 N) available for delicate wafer surfaces. Stainless 316L housing, cleanroom compatible.
🔌
PCB Flatness
PCB warpage measurement in SMT production. The LVDT gauging probe scans across the PCB surface, mapping bow and twist for process control feedback.
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CMM & Measurement Fixtures
Integration into dedicated measurement fixtures for engine parts, turbine blades. Multiple spring-loaded LVDTs configured in a single fixture for multi-point dimensional inspection.
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Medical Device
Implant dimensional inspection — stainless probe, cleanroom compatible. Meets 100% inspection requirements for orthopedic and cardiovascular device manufacturing.
Selection Guide
How to Choose the Right Spring-Loaded LVDT Version
Three main configurations — match your signal conditioning requirement and accuracy level to the right version.
〰️
AC LVDT Version Maximum flexibility
Connect to your existing LVDT signal conditioner or DAQ card with LVDT inputs
Select excitation frequency (2–10 kHz) to match your conditioner
±3V AC differential output
Best for labs and research setups with existing LVDT infrastructure
Lowest sensor cost — signal processing done externally
→ Specify: AC version + stroke + probe tip
📟
DC 4-20mA Version Easiest PLC integration
Direct connection to PLC analog input card — no external conditioner
12–30V DC supply, 4-20mA current loop output
Immune to cable length and electrical noise
Plug-and-play for production gauging systems
Integrated oscillator-demodulator in the sensor housing
→ Specify: DC 4-20mA + stroke + connector
🎯
Precision ±0.05% FS Metrology-grade accuracy
±0.05% FS linearity — half the error of standard version
Temperature-compensated electronics included
For CMM-level inspection and calibration lab use
Allow 30-minute thermal stabilization before measurement
OEM volume supply, custom specification, lead time confirmed at order
→ Contact engineering team for precision spec
Not sure which configuration is right for your application?
Tell us your stroke, target material, required accuracy, and signal interface (PLC model, DAQ card) — our engineers will specify the exact model and probe tip within 24 hours.
Spring-Loaded LVDT Sensor OEM Manufacturer — China Factory
SEGMENsensor manufactures spring-loaded LVDT gauging sensors at our Shenzhen facility. We supply measurement equipment builders, automation integrators, and metrology OEMs worldwide. Mass production lead time confirmed with the quotation; fully custom versions (probe geometry, stroke, IP rating, output, OEM label) are quoted by quantity. CE and RoHS documentation included with every shipment.
10–100 mm Stroke, All Probe Tips
Four standard stroke lengths (10, 25, 50, 100 mm). Ruby, carbide, flat, and needle probe tip options. Custom probe geometries (angled, extended, T-shape) from OEM volume supply.
AC LVDT or Conditioned DC Output
AC version (±3V AC) for connection to existing signal conditioners. DC conditioned version (4-20mA / 0-10V / ±10V) for direct PLC or DAQ connection. Specify at order — no modification cost.
CE, RoHS — Full Compliance Documentation
CE Declaration of Conformity, RoHS statement, and test reports provided with every batch. ISO 9001:2015 production quality management. Calibration certificates on request.
Samples of 1–5 pcs Before Production Order
Engineering sample orders (1–5 pcs) ship in 5–7 days for application testing. Standard production lead time is confirmed with the quotation. Full production from OEM volume supply. Private label OEM quoted on request.
Quick OEM Enquiry — Spring-Loaded LVDT
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Technical and commercial questions answered by SEGMENsensor application engineers.
What is the difference between a spring-loaded LVDT and a standard LVDT sensor?
A standard LVDT requires mechanical coupling between the sensor core and the moving part — the core must be rigidly attached to the target. A spring-loaded LVDT has an internal spring that pushes the probe tip outward, maintaining contact pressure of 0.5–1.5 N against any surface. This allows it to follow target surfaces without mechanical attachment, making it ideal for gauging, probing, and surface following applications. The spring-loaded design enables quick part loading and unloading in automated gauging fixtures without sensor repositioning.
What stroke length should I choose for my spring-loaded LVDT sensor?
Select a stroke where your measurement range occupies 80–90% of the total stroke. For a part tolerance range of ±0.5 mm, a 10 mm stroke LVDT gives comfortable margin and best resolution. For longer travel (e.g., press ram monitoring over 30 mm), choose 50 mm stroke. SEGMENsensor stocks: 10 mm, 25 mm, 50 mm, and 100 mm strokes. Longer stroke = lower resolution at equivalent output. For sub-micron gauging, use 10 mm stroke with ±0.05% FS version and high-resolution signal conditioner.
What probe tip options are available for spring-loaded LVDT gauging sensors?
SEGMENsensor offers four probe tip options: (1) Hardened Ruby ball — standard, wear-resistant, ideal for smooth surfaces; (2) Tungsten carbide ball — for abrasive surfaces, harder than ruby; (3) Flat disc tip — for measuring into grooves or against shoulders; (4) Needle point — for surface profiling and fine groove measurement. Probe tip diameter is typically 1 mm (standard) or 2 mm (optional). Custom probe geometries (angled, extended, T-shape) available from OEM volume supply for fixture integration.
How accurate is a spring-loaded LVDT sensor and can it achieve sub-micron resolution?
Standard linearity is ±0.1% FS — on a 10 mm stroke, this is ±10 µm absolute linearity. Resolution is infinite in the analog domain and depends on your signal conditioner ADC: a 16-bit conditioner on a 10 mm stroke gives theoretical 0.15 µm resolution. SEGMENsensor's precision ±0.05% FS version achieves ±5 µm linearity. For production gauging (e.g., ±0.02 mm tolerance inspection), the standard version exceeds requirements. For CMM-level accuracy, use the precision version with temperature-compensated electronics and allow 30-minute thermal stabilization.
What is the spring contact force and how does it affect the measurement?
Standard spring contact force is 0.5–1.5 N (approximately 50–150 grams-force), depending on model and probe extension. This force is sufficient to maintain contact on rigid metallic or ceramic surfaces without disturbing the part position in a fixture. For very lightweight parts (thin foils, small PCBs), excessive spring force can deflect the part and introduce measurement error — in these cases, specify the low-force variant (0.2 N) or use a non-contact alternative. Spring force decreases slightly as the probe retracts (compressed spring) and increases as the probe extends.
Can spring-loaded LVDT sensors be used in washdown or coolant spray environments?
Yes, with the appropriate protection option. Standard spring-loaded gauging LVDTs are rated IP54 (splash-resistant). For CNC machining environments with coolant mist, specify the IP67 sealed version — the spring cavity and cable entry are sealed with elastomeric boots and O-rings. PTFE wiper seals prevent coolant ingress into the linear bearing. The probe rod is stainless steel 316L. For full immersion (e.g., underwater gauging in parts washers), specify the IP68 version. Note: acidic coolants may attack the spring material — request stainless steel spring for aggressive coolants.
What output signal does a spring-loaded LVDT produce and how does it connect to a data acquisition system?
SEGMENsensor spring-loaded LVDTs are available in two output configurations: (1) Raw AC LVDT output (±3V AC, 2–10 kHz excitation) — connects to LVDT signal conditioners, measurement amps, or dedicated DAQ cards with LVDT input modules; (2) DC conditioned output (4-20mA or 0-10V) — connects directly to any PLC analog input, panel meter, or DAQ card. The DC version includes an integrated oscillator-demodulator signal conditioner, requires 12–30V DC supply. For PC-based gauging systems, the 0-10V version interfaces easily with standard data acquisition hardware.
What is the MOQ and lead time for spring-loaded LVDT sensors from a China factory?
Standard spring-loaded LVDT sensors (10, 25, 50 mm stroke, 4-20mA DC output): OEM volume supply, production lead time is confirmed with the quotation. Samples of 1–5 pcs for testing ship in 5–7 days. Custom specifications (probe tip geometry, stroke, output range, IP67/68, OEM label, connector type): OEM volume supply, production lead time confirmed with the quotation. Full private-label OEM: quoted by quantity. CE and RoHS documentation included. Factory: SEGMEN (Shenzhen) Industrial Development Co., Ltd., Registration No. 91440300MAEUXXQU04, Shenzhen, Guangdong, China.
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