1. Althen Sensors
  2. Sensors
  3. Pressure sensors
  4. Pressure sensor modules
  5. MDM291 Differential pressure sensor

MDM291 Differential pressure sensor

Differential pressure sensor with fully welded stainless steel design and 20 MPa static pressure resistance.


Key features

  • Differential pressure range: 0.35 bar to 20 bar
  • Fully welded structure — no o-rings
  • Static pressure resistance: up to 200 bar (20 MPa)
  • Output: 70 mV (typical) bridge signal
  • Long-term stability: ±0.3 to ±0.5%FS/year
  • High corrosion resistance with SS316L
  • Compact OEM design with silicone oil-filled isolation

About the MDM291 Welded differential pressure sensor module

The MDM291 is a welded differential pressure sensor designed for OEM integration. Its stainless steel 316L diaphragms and fully welded construction make it ideal for applications requiring compatibility with aggressive, conductive, or high-pressure fluids. By isolating both high and low-pressure sides and transmitting differential pressure via silicone oil to a piezoresistive sensor die, the sensor delivers stable, accurate readings without deformation.

Usage conditions

This sensor operates in harsh conditions with a wide working temperature range of -40°C to +125°C and a compensated range of 0°C to +70°C. The unit tolerates high vibration (10g RMS) and shock (100g, 11ms), making it suitable for challenging industrial environments.

Possible applications

  • Flow measurement (Venturi, vortex)
  • Gas and liquid differential monitoring
  • Pressure calibration systems
  • HVAC differential control
  • Process automation and control systems

Advantages of choosing this product

The MDM291 offers a leak-proof, o-ring-free design that increases durability and chemical resistance. With high interchangeability, robust output, and a compact design (Ø19 mm), it's ideal for differential measurement systems where reliability and space efficiency matter.

Other important features

  • Electrical output: 70 mV DC
  • Input impedance: 2–8 kΩ | Output impedance: 3.5–6 kΩ
  • Thermal error (zero/span): ±0.75% to ±1.0%FS at 35°C
  • Electrical connection: 100 mm flexible silicone wires
  • Threaded pressure ports (G1/4, G1/2, M20x1.5, etc.)
  • Sealing options: EPDM, FKM, FVMQ or welded ends

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
Pressure nonlinearity ±0.15, MAX ±0.25 %FS,BFSL
Pressure repeatability ±0.05, MAX ±0.075 %FS
Pressure hysteresis ±0.05, ±0.075 %FS
Zero output ±2.0 mV DC
Output/Span MIN 70 mV DC
Zero thermal error ±0.75, MAX ±1.0 %FS, @35℃
Span thermal error ±0.75, MAX ±1.0 %FS, @35℃
Compensation temp. range 0 ~ 70 ℃
Operating temp. range -40~125 ℃
Storage temp. range -40~125 ℃
Long-term stability error ±0.3, MAX ±0.5 %FS/Year

Related products

Need something else?

MDM290 Differential pressure sensor module

  • OEM sensor for differential pressure
  • High static pressure up to 200 bar
  • Compact, reliable and media-isolated
Datasheet View product

MPM489 ATEX pressure transmitter

  • Intrinsically safe & Ex-proof versions
  • Pressure range up to 1000 bar
  • Stainless steel housing
Datasheet View product