
OBS-ONE PM unit
On-board Emissions Measurement System
The OBS-ONE PM Unit is an on-board emissions measurement system designed to collect and measure particulate matter (PM) in real-world driving conditions. It uses a high-precision partial-flow gravimetric sampling method paired with real-time particle monitoring. A built-in venturi flow meter ensures accurate proportional sampling even during transient exhaust flow conditions.
Why Choose OBS-ONE PM unit
Certified Accuracy – Meets EPA CFR Part 1065 subpart J for regulatory-grade PM measurement.
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Compact & Vehicle-Ready – Compact, lightweight, and easily mounts on vehicles with a modular, front-access design.
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Dual Measurement Capability – Offers gravimetric filter collection plus real-time PM concentration tracking.
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Integrated Control – Operates via the unified HORIBA ONE software platform for streamlined system management.

Key Advantages of OBS-ONE PM unit
Compliance-Ready Design
Delivers trusted PM data for regulatory and certification needs.
Compact & Easy Mounting
Quick to install and maintain even on space-constrained vehicle setups.
Combined Sampling & Sensing
Simultaneously captures batch samples and live PM data for comprehensive analysis.
Unified System Control
Centralizes control and diagnostics for OBS-ONE and other modules in a single interface.
Technical Specifications of OBS-ONE PM unit
Measuring Principles | Batch sampling: Filter gravimetric method Real-time PM measurement : Diffusion charging method |
Measuring Ranges (Real-time PM sensor) | 0 to 2500 mm/cm3 (Concentration after dilution) |
Dilution Method | Partial flow dilution method (Proportional sampling mode/Fixed dilution ratio mode) |
Signal for Gas Sampling | Exhaust gas flow rate: Isolated analog signal (0-10 V) |
Flow Rate of Diluted Gas | 10 to 15 L/min (Under the conditions of 20 deg.C and 101.3 kPa) |
Filter Holder | Diameter 47 mm, Effective diameter 26.2 mm (Without backup filter) |
Particle Pre-classifier (Cyclone) | 99% penetration of particle size of less than 1 μm 50% cut off point: particle size between 2.5 and 10 μm |
Power Requirements | DC 24 V |
Power Consumption | Max. 0.6 kVA |
Dimensions | 350(W) x 470(D) x 460(H) mm (Excluding controller and protruding objects) |
Mass | Approx. 45 kg (Excluding controller) |
Operating Conditions | Temperature: 0 to 40 deg.C (During operation) Relative humidity: less than 80% Altitude: 0 to 2000 m above sea level |
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