1. Althen Sensors
  2. Sensors
  3. Linear position sensors
  4. Intrinsically safe position sensors
  5. M111 Rugged stand-alone linear position sensor

M111 Rugged stand-alone linear position sensor

Reliable position measurement in harsh and hazardous environments. Built for durability and precision with ATEX/IECEx/UKEX approval.


Key features

  • Intrinsically safe for mining and hazardous areas (Ex I/II M1/GD)
  • Heavy-duty 12.6 mm push rod and stainless-steel housing
  • Measurement ranges from 0–5 mm to 0–800 mm
  • Sealing to IP67 and temperature range from –40 °C to +80 °C
  • Infinite resolution and high linearity up to ±0.25% FSO
  • Wide selection of mechanical mounting and electrical connection options

Performance highlights

The M111 sensor delivers high precision and robust performance in extreme environments. It features a heavy-duty design with a larger 12.6 mm stainless steel push rod, making it ideal for vibration-intensive applications or longer measurement strokes. The sensor provides a linear analogue output (0.5–4.5 V ratiometric) and infinite resolution, with excellent repeatability and low noise.

Usage conditions

With ATEX / IECEx / UKEX approval and Ex I/II M1/GD classification, the M111 is designed for use in potentially explosive gas and dust atmospheres, including mining. It operates reliably from –40 °C to +80 °C, and is sealed to IP67 to withstand demanding industrial settings. The sensor can be used with cable lengths up to 1000 metres (with galvanic isolation), and is available with either three-wire or five-wire configurations.

Possible applications

  • Underground and surface mining equipment
  • Industrial process monitoring
  • Scientific test rigs
  • Linear displacement control in ATEX zones
  • Position sensing in hazardous dust and gas environments

Advantages of choosing this product

The M111 offers the benefits of non-contact inductive sensing with no mechanical wear, ensuring long service life and minimal maintenance. Its compact size, rugged housing and multiple output and mounting configurations make it easy to integrate into space-constrained systems. With custom-calibrated travel lengths and intrinsic safety, it’s a dependable choice for high-risk environments.

Other important features

  • Stainless steel body and rod construction
  • Optional sprung push rod, magnetic tip, dome end, or rod-eye
  • Certified for use with up to 1000 m of cable
  • Compatible with Althen X005 galvanic isolation amplifier
  • Meets EMC standards: EN 61000-6-2, EN 61000-6-3
  • Shock resistance up to 40 g, vibration up to 10 g

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.

Talk to an expert

Talk to our experts

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.

Talk to an expert

Technical Specifications

Specification Value
Body diameter 35 mm
Body length (axial) Calibrated travel + 163 mm
Body length (radial) Calibrated travel + 186 mm
Push rod diameter 12.6 mm
Travel range 0–5 mm to 0–800 mm
Independent linearity ≤ ±0.25% FSO @ 20 °C (up to 450 mm), ≤ ±0.5% FSO @ 20 °C (over 450 mm)
Temperature coefficients < ±0.01%/°C Gain, < ±0.01%FS/°C Offset
Resolution Infinite
Noise < 0.02% FSO
Frequency response > 10 kHz (–3 dB)
Sealing IP67
Operating temperature –40 °C to +80 °C
Storage temperature –40 °C to +125 °C
Shock 40 g (IEC 68-2-29)
Vibration 10 g (IEC 68-2-6)
MTBF 350,000 hrs @ 40 °C
Supply voltage +5 VDC (4.5–5.5 V)
Output 0.5–4.5 V ratiometric
Intrinsic safety Ex I/II M1/GD, Ex ia IIC T4 Ga, Ex ia IIIC T135°C Da, Ex ia I Ma
Cable length Up to 1000 m (with galvanic barrier)
EMC compliance EN 61000-6-2, EN 61000-6-3

Related products

Need something else?

M112 Intrinsically safe gauge head position sensor

  • Compact 19 mm diameter with IP67 sealing
  • Non-contact inductive technology for long life
  • Certified for use in explosive mining and gas/dust zones
Datasheet View product

M114 Submersible stand-alone linear position sensor

  • Intrinsically safe for mining zones: Ex I/II M1/1GD
  • Travel set to customer requirement: 5 to 800 mm
  • Fully submersible up to 100 meters, IP68 10 bar / IP69K
Datasheet View product

M115 Rugged submersible stand-alone linear position sensor

  • ATEX / IECEx / UKEX certified for mining use
  • Travel range up to 800 mm with strong push rod
  • IP68/IP69K sealing for full submersion
Datasheet View product