Factory-direct LVDT linear displacement sensors for OEM equipment builders worldwide. Spring-loaded gauging probes, separate-core transducers, and pen-type LVDT sensors — contactless, wear-free, ±0.1% linearity. CE certified, IP67 rated, custom stroke and output on request.
A SEGMENsensor LVDT (linear variable differential transformer) is a contactless inductive displacement sensor: a free ferromagnetic core moves inside primary and secondary coils, and the differential output is proportional to displacement, with no friction or wear. Three series cover strokes from ±0.5 mm to ±500 mm with AC, DC analog or RS485 output.
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.
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.
Every unit is tested before shipment. Photos from our own production and test lines.
What is an LVDT displacement sensor? An LVDT (Linear Variable Differential Transformer) is a contactless inductive displacement transducer that measures linear position without friction or wear. A free-floating ferromagnetic core moves inside a wound coil assembly — the differential output voltage is precisely proportional to displacement. Zero mechanical contact means theoretically infinite service life. SEGMENsensor manufactures LVDT sensors as a factory-direct OEM supplier in Shenzhen, China, with strokes from ±0.5 mm to ±500 mm, linearity ±0.1% FS, and outputs in 4-20 mA, 0-10 V, or RS485.
Four series covering gauging probes, spring-loaded sensors, separate-core transducers, and long-stroke pen-type LVDTs — all with DC or AC output options.
Ultra-high precision spring-loaded LVDT gauging probes for dimensional inspection, surface profiling, and quality control. Ruby or carbide tip. Resolution limited only by signal conditioner. Ideal for CMM integration and automated inspection lines.
Separate-core LVDT with rigid core rod attachment. The coil body is fixed while the core rod is bolted to the moving part — ideal for hydraulic valve spool position, actuator stroke, and injection moulding machine screw position monitoring.
Long-stroke pen-type LVDT with integrated signal conditioner. Available in 4-20 mA, 0-10 V, and RS485/Modbus RTU outputs. Single-cable connection to PLC analog or digital input. Ideal for press machines, test rigs, and machine tool axis monitoring.
All parameters customizable for OEM applications. LVDT transducer OEM China — custom stroke, output, connector, and housing on request.
| Parameter | SDVH Gauging Probe | SDVG Separate-Core | SLT Pen-Type |
|---|---|---|---|
| Stroke (Full Range) | ±0.5 / ±1 / ±2 / ±5 mm | ±2 / ±5 / ±10 / ±25 / ±50 / ±100 mm | ±10 / ±25 / ±50 / ±75 / ±100 / ±150 / ±200 / ±250 / ±500 mm |
| Linearity | ±0.1% FS (ultra-high acc.) | ±0.25% FS (standard) | ±0.25% FS standard / ±0.1% FS optional |
| Resolution | Infinite (analog signal) | Infinite (analog signal) | Infinite (analog) / 0.001 mm (RS485 digital) |
| Repeatability | ±0.01% FS | ±0.01% FS | ±0.01% FS |
| Output Signal | AC differential / DC 0–10V / 4-20mA | AC differential / DC 0–10V / 4-20mA | 4-20mA / 0-10V / ±10V / RS485 Modbus |
| Excitation (AC type) | 1–10 kHz, 1–5 Vrms | 1–10 kHz, 1–5 Vrms | Built-in DC-DC converter (10–30V DC supply) |
| Supply Voltage (DC type) | 10–30V DC | 10–30V DC | 10–30V DC |
| Operating Temp. | -40°C to +125°C | -40°C to +125°C | -40°C to +85°C |
| Protection Rating | IP67 | IP67 | IP67 |
| Housing Material | 303 / 316L Stainless Steel | 303 / 316L Stainless Steel | 303 Stainless Steel / Aluminium alloy |
| Electrical Connection | Integral cable / M12 × 1 connector | Integral cable / M12 × 1 connector | M12 × 1 connector / custom cable |
| Certifications | CE RoHS | CE RoHS | CE RoHS |
| Samples | 1–5 pcs, 5–7 working days | 1–5 pcs, 5–7 working days | 1–5 pcs, 5–7 working days |
| Lead Time | Confirmed with the quotation | Confirmed with the quotation | Confirmed with the quotation |
One-page datasheet with all ranges, accuracy classes, output options, supply voltage, process connections, materials, temperature limits, IP rating, dimensions and the ordering code. No registration required.
Understanding LVDT operating principle helps engineers select the correct variant for their OEM application.
An AC voltage (1–10 kHz) is applied to the primary coil, creating an alternating magnetic field throughout the cylindrical coil former.
The ferromagnetic core moves inside the bore. Its position determines how much magnetic flux couples into each of the two secondary coils — one increases while the other decreases.
The two secondary voltages are subtracted (differential connection). The result is a voltage proportional to displacement with excellent linearity — positive or negative depending on direction.
A built-in ASIC conditioner (DC-powered models) demodulates the AC signal to a 4-20 mA, 0-10 V, or RS485 output. AC output models connect directly to external LVDT signal conditioners.
LVDT sensors excel in environments with vibration, temperature extremes, and demanding duty cycles where contact-based sensors fail. Custom LVDT OEM factory — specify your application below.
SEGMENsensor has manufactured LVDT displacement sensors for OEM equipment builders since 2019. We are a direct factory — not a distributor — with in-house winding, signal conditioning PCB assembly, and calibration traceable to national standards.
Choose the right displacement sensor for your OEM application. LVDT is the best choice for short-stroke, vibration-rich, high-accuracy environments.
| Criterion | LVDT (SEGMENsensor) | Magnetostrictive | Linear Potentiometer | Draw-Wire Encoder |
|---|---|---|---|---|
| Mechanical Contact | ✓ None — frictionless | ✓ None | ✗ Wiper contact | Wire friction |
| Service Life | ✓ Infinite (no wear) | ✓ Very long | Limited (10M cycles) | Wire fatigue limit |
| Best Stroke Range | ±0.5 mm – ±500 mm | 25 mm – 8,000 mm | 10 mm – 1,000 mm | 100 mm – 50,000 mm |
| Accuracy | ✓ ±0.1% FS | ✓ ±0.01% FS | ±0.1–±1% FS | ±0.1–±0.5% FS |
| Vibration Immunity | ✓ Excellent | Good | Poor (wiper bounce) | Moderate |
| Absolute Position | Absolute (power-cycle safe) | ✓ Absolute | Absolute | Absolute |
| OEM Cost | ✓ Low–Medium (factory direct) | Medium–High | ✓ Lowest | Low–Medium |
Choose an LVDT for linear travel that needs non-contact, wear-free sensing; an RVDT when the axis rotates; and a linear potentiometer only when low cycle counts and a simple DC voltage divider are acceptable. SEGMENsensor LVDTs cover ±0.5 mm to ±500 mm with ±0.25% FS linearity as standard and ±0.1% FS optional.
An LVDT measures linear displacement; an RVDT (rotary variable differential transformer) measures rotation angle. Both use one primary and two secondary windings with a moving ferromagnetic core or rotor, so neither has a sliding electrical contact. If the part you track moves in a straight line, use an LVDT; if it turns on a shaft, an RVDT is the matching principle.
A linear potentiometer is adequate when the axis moves few cycles, vibration is low and a plain voltage-divider signal is enough. Its wiper slides on a resistive track, so the track wears with every stroke and contact noise rises under vibration. For valve spools, test rigs and in-line gauging that run millions of strokes, a non-contact LVDT avoids that wear mechanism.
| Criterion | LVDT | RVDT | Linear potentiometer |
|---|---|---|---|
| Motion measured | Linear displacement | Rotation angle | Linear displacement |
| Sensing contact | None — core does not touch the coil | None — rotor does not touch the windings | Wiper slides on a resistive track |
| Wear over life | No electrical wear part | No electrical wear part | Track and wiper wear with every stroke |
| Electronics | AC type: 1–10 kHz excitation + conditioner; DC type: built-in, 10–30 V DC supply | AC excitation + demodulator | DC voltage divider |
| Output options | AC differential / 0–10 V / ±10 V / 4–20 mA / RS485 Modbus | AC or conditioned DC (per supplier) | Ratiometric voltage |
| Typical fit | Gauging probes, valve spool and actuator stroke, test machines | Valve shaft angle, rotary actuator feedback | Low-cycle position feedback, manual adjusters |
| SEGMENsensor range | SDVH, SDVG and SLT series, ±0.5 mm to ±500 mm | Not in our standard range — send the requirement for review | Not supplied |
Picking the LVDT type: for dimension checks with a spring-returned tip, see the spring-loaded LVDT sensor and the LVDT gauging probe; for a core fixed to the moving part, use the SDVG separate-core series above. The background is explained in What Is an LVDT Sensor?.
Send stroke, linearity, output, supply voltage, temperature and connection. An engineer reviews it and replies within 24 hours; qualification samples of 1–5 pcs ship in 5–7 days, and production is planned around your annual volume.
Controlled coil winding, PCB assembly, and calibration. Batch traceability on every order.
EMC and LVD directive compliance. CE declaration provided for EU customs clearance.
All standard LVDT models are RoHS compliant. Declaration of conformity on request.
Core engineering team with 20+ years of technical experience. Factory direct — not a distributor or trading company.
UK Conformity Assessed — required for Great Britain market entry. Equivalent to CE for England, Scotland and Wales.
Short answers to questions engineers ask before ordering. Values come from the specification table on this page; anything not listed there is confirmed with the quotation.
An LVDT gauging probe is a spring-loaded LVDT whose tip touches the part to check its dimensions; an LVDT position sensor follows a moving machine part. Buy the SDVH gauging probe (±0.5 to ±5 mm, ±0.1% FS) for inspection, and the SDVG separate-core LVDT (±2 to ±100 mm, core fixed to the moving part) or the SLT pen-type (±10 to ±500 mm, 4–20 mA, 0–10 V or RS485) for position feedback. For a quote, send stroke, mounting, output and quantity.
Yes. A ±50 mm stroke is a standard value in both the SLT pen-type and the SDVG separate-core series, and ±0.1% FS linearity is an option on the SLT pen-type; SDVG is specified at ±0.25% FS. Both have ±0.01% FS repeatability and a 10–30 V DC supply for DC types. Qualification samples are 1–5 pcs in 5–7 working days; production lead time and MOQ are confirmed with the quotation. Send stroke, linearity class, output, supply voltage and quantity.
| Item | What can be specified | Limit / not suitable |
|---|---|---|
| Stroke | SDVH ±0.5 to ±5 mm; SDVG ±2 to ±100 mm; SLT ±10 to ±500 mm; custom stroke within the series range | Beyond ±500 mm: use a magnetostrictive position sensor (25–8,000 mm) |
| Linearity | SDVH ±0.1% FS; SDVG ±0.25% FS; SLT ±0.25% FS standard, ±0.1% FS optional; ±0.01% FS repeatability on all series | ±0.1% FS is not listed for the SDVG series |
| Output and supply | SDVH / SDVG: AC differential, 0–10 V or 4–20 mA; SLT: 4–20 mA, 0–10 V, ±10 V or RS485 Modbus; 10–30 V DC for DC types | RS485 output is listed only on the SLT pen-type |
| Temperature | SDVH and SDVG -40 °C to +125 °C; SLT -40 °C to +85 °C | SLT is not listed above +85 °C |
| Connection and labelling | Integral cable or M12 × 1 connector; non-standard connector, cable length and private label evaluated per project | — |
| Pressure and motion | IP67 housing in stainless steel (SLT also aluminium alloy) | Not for mounting inside a hydraulic cylinder above 100 bar (use a magnetostrictive sensor); rotary axes (RVDT) are not in the standard range |
Common questions from OEM engineers. Can't find your answer? Email info@segmensensor.com — we reply within 24 hours.
Tell us your stroke range, required output, operating temperature, and quantity. Engineering team replies within 24 hours.
SEGMEN (Shenzhen) Industrial Development Co., Ltd. · Shenzhen, China · info@segmensensor.com · +86 138 2870 4591
SEGMENsensor manufactures complementary position and flow sensors — all from the same factory, same certifications, same lead time.