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Visibility Sensor 6400

The Model 6400 Visibility Sensor offered by Met One Instruments Powered by Acoem is designed to monitor visibility conditions over a range of 20ft-50miles (6m-80km). The Model 6400 includes both digital and relay outputs. The Digital RS232 output at 300-38,400 Baud can be used to indicate the present visibility, provide diagnostic information, and provide access to the configuration and calibration options. The SPDT relay with configurable pull in and drop out set points can provide signals to a VMS or other optional user system.

Met One takes advantage of Belfort’s proven experience with visibility technology in re-designing this new sensor for applications which require high accuracy over an extended range of visibility. These sensors are designed to provide both accuracy and reliability in a cost effective package. The Model 6400 features easy field serviceability. Applications include synoptic stations, lighthouses, highways, resort areas, as well as shipboard and other marine platforms.

Operations / Interface

Visibility is detected using widely accepted principles of forward scattering. A high output infrared LED transmitter projects light into a sample volume and light scattered in a forward direction is collected by the receiver. The light source is modulated to provide excellent rejection of background noise and natural variations in background light intensity. The sensors can asynchronously stream RS232 visibility data at user configured intervals, or can be operated in the polled mode, outputting information only when asked. Visibility is also compared to the preset relay thresholds, so that when an alarm condition is reached, the relay output is switched. Visibility thresholds can be set to any value within the instrument range.


  • High Accuracy
  • Proven Optical Technology
  • Digital and Relay Outputs
  • Selectable Relay Thresholds
  • Compact, Lightweight Design
  • Corrosion Resistance
  • Meteorological Optical Range (MOR)
  • IP66 Ingress Protection


Specifications are subject to change at any time.
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