ACT LVDT Displacement Transducer

High accuracy
High cycle life
Infinite resolution
Stainless steel

RDP LVDT How it Works

   Data sheet (316kb)
These transducers are for displacement / position measurement. They make an accurate position measurement of the movement of the armature (the sliding part) relative to the body of the displacement transducer.

This transducer uses the Linear Variable Differential Transformer (LVDT) principle which means that it is probably the most robust and reliable position sensor type available. The strength of the LVDT sensor's principle is that there is no electrical contact across the transducer position sensing element which for the user of the sensor means clean data, infinite resolution and a very long life.

This series of displacement transducer is available as either an unguided, captive or spring return version.

LVDT transducers require external signal conditioning as detailed in the 'Electronics' section of this website.

Unguided version.
On our unguided LVDTs the armature assembly is a separate component, to make a measurement the user must guide the armature inside the body without touching the sides. Unguided position measurement transducers are appropriate where external guidance is available and give truly non-contact operation
A = 9mm
ID = 6.8mm
D1 = 20.6mm
D3 = 4.75mm
D4 = 5.97mm
TF = M5x0.8
Type Range Linearity error (% F.S.) L X (nom) Total weight Armature weight TF Over-Travel Sensitivity (nom)
Inward over-travel
ACT500 ±12.5mm <±0.5/±0.25/±0.1 127mm 43mm 170g 17g 15mm 16mm 0.7V/V
ACT1000 ±25mm <±0.5/±0.25/±0.1 155mm 68mm 227g 23g 15mm 22mm 0.9V/V
ACT2000 ±50mm <±0.5/±0.25/±0.1 270mm 81mm 320g 37g 15mm 16mm 1.5V/V
ACT3000 ±75mm <±0.5/±0.25/±0.1 380mm 120mm 454g 55g 15mm 29mm 1.5V/V
ACT4000 ±100mm <±0.5/±0.25/±0.1 427mm 132mm 568g 71g 15mm 16mm 3.2V/V
ACT6000 ±150mm <±0.5/±0.25 617mm 183mm 824g 100g 15mm 16mm 2.4V/V
ACT8000 ±200mm <±0.5/±0.25 808mm 259mm 1.2kg 140g 29mm 27mm 1.5V/V

Captive guided version.
Our captive guided displacement transducer has bearings to guide the armature inside the measurement sensor. Captive LVDTs are for position measurement applications where guidance may be poor and end bearings may be required.
A = 24mm
D1 = 20.6mm
TR = M5x0.8, 11mm
TF = M5x0.8
Type Range Linearity error (% F.S.) L X (nom) D3 Total weight TF Over-Travel Sensitivity (nom)
Inward over-travel Outward over-travel
ACT500C ±12.5mm <±0.5/±0.25/±0.1 152mm 38mm 4.75mm 284g 15mm 10mm 12mm 0.7V/V
ACT1000C ±25mm <±0.5/±0.25/±0.1 180mm 63mm 4.75mm 340g 15mm 13mm 10mm 0.9V/V
ACT2000C ±50mm <±0.5/±0.25/±0.1 295mm 76mm 4.75mm 511g 15mm 10mm 14mm 1.5V/V
ACT3000C ±75mm <±0.5/±0.25/±0.1 406mm 114mm 4.75mm 653g 15mm 24mm 15mm 1.5V/V
ACT4000C ±100mm <±0.5/±0.25/±0.1 452mm 127mm 4.75mm 710g 15mm 8mm 14mm 3.2V/V
ACT6000C ±150mm <±0.5/±0.25 643mm 178mm 4.75mm 1.0kg 15mm 12mm 17mm 2.4V/V
ACT8000C ±200mm <±0.5/±0.25 833mm 254mm 4.75mm 1.4kg 32mm 22mm 25mm 1.5V/V
ACT10000C ±250mm <±0.5/±0.25 1030mm 305mm 4.75mm 1.6kg 27mm 34mm 35mm 2.0V/V
ACT15000C ±380mm <±0.5 1435mm 406mm 4.75mm 2.1kg 19mm 13mm 13mm 3.2V/V
ACT18500C ±470mm <±0.5 1702mm 508mm 6.00mm 2.5kg 27mm 5mm 33mm 3.6V/V

Spring return version.
Our spring displacement transducer has bearings to guide the armature inside the measurement sensor and a spring which pushes the armature to the fully out position. Spring return LVDTs are appropriate where it is not possible to connect the transducer armature to the moving component being measured.
A = 9mm
D1 = 20.6mm
D3 = 4.75mm
Type Range Linearity error (% F.S.) L X (nom) Total weight Spring force (nom) Over-Travel Sensitivity (nom)
Spring force at X Spring rate Inward over-travel Outward over-travel
ACT500A ±12.5mm <±0.5/±0.25/±0.1 133mm 38mm 184g 1.3N 0.2N/cm 1mm 13mm 0.7V/V
ACT1000A ±25mm <±0.5/±0.25/±0.1 161mm 63mm 227g 2.0N 0.3N/cm 3mm 10mm 0.9V/V
ACT2000A ±50mm <±0.5/±0.25/±0.1 276mm 75mm 398g 1.8N 0.2N/cm 8mm 14mm 1.5V/V
ACT3000A ±75mm <±0.5/±0.25/±0.1 387mm 114mm 483g 6.0N 0.4N/cm 15mm 15mm 1.5V/V


Excitation/supply (acceptable)0.5V to 7V rms, 2kHz to 10kHz (sinusoidal) Temperature coefficient (span) ±0.01% F.S. /C (typical)
Excitation/supply (calibrated)5V rms, 5kHz (sinusoidal) Operating temperature range -50C to 125C
Output load100k Ohms Electrical termination 2m (integral cable) Longer available to order.

Connection details

Options and accessories

TM0315 Operating temperature range (maximum) = 200C  ( ±100mm maximum )
Rod-end bearings for captive-guided position transducers
Alternative probe tips for LVDTs
Mounting block
E74 In-Line Signal Conditioning Amplifiers

All dimensions and specifications are nominal. 20170119
Due to our policy of on-going development, specifications may change without notice. Any modification may affect some or all of the specifications for our equipment.
USA & Canada
RDP Electrosense
2216 Pottstown Pike
Pottstown, PA 19465
Tel: 610-469-0850
Tel: 800-334-5838
Fax: 610-469-0852
Rest of the world
RDP Electronics Ltd
Grove Street, Heath Town
Wolverhampton, West Midlands, WV10 0PY
United Kingdom

Tel: +44 1902 457512
Fax: +44 1902 452000