1. Althen Sensors
  2. Sensors
  3. Linear position sensors
  4. Intrinsically safe position sensors
  5. M115 Rugged submersible stand-alone linear position sensor

M115 Rugged submersible stand-alone linear position sensor

Heavy-duty and intrinsically safe linear position sensor designed for submerged applications in mining and hazardous environments. Built for durability and precision, even under high vibration or deep water.


Key features

  • ATEX / IECEx / UKEX approved for mining and hazardous areas (Ex I/II M1/1GD)
  • Robust 316 stainless steel construction with IP68 10bar/IP69K sealing
  • Travel range from 5 mm up to 800 mm, factory calibrated
  • Strong 12.6 mm push rod with optional rod eye, magnetic tip or dome end
  • High linearity (±0.25% FSO up to 450 mm), infinite resolution
  • Five-wire connection recommended for long cable runs (up to 1000 m)

Performance highlights

The M115 linear position sensor offers high precision and repeatability in harsh environments. Its non-contact inductive technology eliminates mechanical wear, while its strong construction and EMC protection ensure long-term performance. The sensor delivers a linear analog output proportional to displacement, calibrated to customer requirements between 5 mm and 800 mm.

Usage conditions

Designed for full submersion, the M115 is IP68 sealed to 10 bar and IP69K rated. It withstands operating temperatures from -40°C to +80°C and offers stable performance even under heavy vibration. This model is ideally suited for horizontal mounting in demanding environments.

Possible applications

  • Underground and open-pit mining equipment
  • Hydraulic and pneumatic actuators
  • Subsea control systems
  • Heavy-duty industrial machinery
  • Drilling and tunneling equipment

Advantages of choosing this product

With its ATEX, IECEx and UKEX certifications, the M115 ensures safe operation in potentially explosive gas, dust and mining environments. The rugged 316 stainless steel design offers long service life, while optional configurations—like spring-loaded rods or custom cable lengths—make it adaptable to specific use cases.

Other important features

  • Intrinsically safe electronics (EX07 system)
  • Optional spring-loaded push rod (extend or retract)
  • Custom body fittings and rod configurations
  • 3- or 5-core cable options up to 150 m
  • Compatible with X005 galvanic isolation amplifier

Do you need this sensor for your next project?

Request a no-obligation quote or send us your contact details for a free, no-obligation consultation. Our sales engineers will then contact you within a maximum of 1 to 2 working days.

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Not exactly what you are looking for? We offer standard sensors, but can also help you with sensors adapted for you or a fully customised measurement solution. Contact us for advice or pricing.

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Technical Specifications

Specification Value
Body diameter 35 mm
Body length (Axial) Calibrated travel + 168 mm
Body length (Radial) Calibrated travel + 189 mm
Push rod extension Calibrated travel + 7 mm, Ø12.6 mm
Linearity (≤450 mm) ≤ ±0.25% FSO @ 20°C
Linearity (>450 mm) ≤ ±0.5% FSO @ 20°C
Temperature coefficients < ±0.01%/°C Gain & < ±0.01%FS/°C Offset
Frequency response > 10 kHz (-3 dB)
Resolution Infinite
Noise < 0.02% FSO
Operating temperature -40°C to +80°C
Storage temperature -40°C to +125°C
Sealing IP68 10bar / IP69K
Intrinsic safety certifications Ex I/II M1/1GD, Ex ia IIC T4 Ga, Ex ia IIIC T135°C Da, Ex ia Ma
Sensor input parameters (no cable) Ui: 11.4V, Ii: 0.20A, Pi: 0.51W, Ci: 1.16µF, Li: 50µH
Sensor input parameters (with cable) Ci: 1.36µF, Li: 860µH (for 1 km cable)
Cable length Up to 1000 m (≤200 nF, ≤810 µH total)
MTBF 350,000 hrs @ 40°C Gf
Output 0.5 – 4.5 V (ratiometric with supply)
Supply voltage +5 VDC (4.5 – 5.5 V)
Load resistance 5 kΩ minimum

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