VPF-510 Visibility Sensor

Model Number: VPF-510
Manufacturer: Biral
Product Brochure: Download

The VPF-510 Visibility sensor offers reliable visibility measurement in a robust and highly corrosion resistant package


VPF-510 Visibility Sensor

The VPF-510 Visibility sensor offers reliable visibility measurement in a robust and highly corrosion resistant package. The serial digital output supplemented by analogue outputs and switching relays makes this sensor particularly suited to offshore and marine applications.

The sensor can be configured to report either Meteorological Optical Range (MOR) or extinction coefficient (EXCO) in the serial data interface and on the voltage or current outputs. To further increase flexibility the sensor measurement range is configurable for the analogue outputs. When the sensor is required to drive a local warning beacon, sign or fog horn the relays can be used.

As standard the sensor is fitted with an extensive self-test monitoring capability which includes window contamination monitoring and output compensation. The VPF-510 can be AC mains or low voltage DC powered and hood heaters are available for use in areas prone to snow.

The sensor is fitted with 6m cables and is constructed from hard coat anodised dip brazed aluminium for superb corrosion resistance.

  • MOR or EXCO output
  • Highly corrosion resistant hard coat anodised finish
  • Window contamination monitoring and compensation
  • Serial digital and analogue outputs
  • Visibility threshold switching relays
  • 6m flying lead connections
  • VPF-500 replacement

Technical Description

Like all VPF series sensors the VPF-510 enclosure is constructed from dip-brazed aluminium with a hard coat anodised finish. This combination results in a sensor that offers superb abrasion and corrosion resistance. It is not unusual for VPF series sensor to be still operating after 20 years’ service in marine environments.

The 45° forward scatter angle and 850nm infrared light source used by the VPF-510 provide the best possible visibility measurement accuracy in all weather conditions. Visibility is output as Meteorological Optical Range (MOR) or extinction coefficient (EXCO) according to the user’s requirement.

In common with all Biral visibility and present weather sensors the VPF-510 uses 2kHz modulation of the light source combined with narrow pass band optical filters and synchronous detection at the receiver to ensure the measurement is not affected by bright or flashing lights. This design also ensures the sensor accurately reports visibility during precipitation. The horizontal hood design eliminates the problems caused by surface reflections that are a source of error in sensors employing look down hood geometries.

The optical windows of the sensor are fitted with low power heaters to prevent the formation of condensation. Window contamination monitoring and compensation allows the visibility output to maintain its accuracy even as dirt builds up on the optical surfaces. The sensor reports the window contamination in the output message using two stages of warning flags allowing cleaning to take place in a convenient manner.

Communication with the sensor is over a RS232 serial data link; RS422 or RS485 communications are optionally available. ASCII encoded data is used and the sensor can operate in either a polled or broadcast modes. The data message can include a time stamp from the internal real time clock in addition to the standard visibility and self-test information. The sensor is supplied with two user configurable threshold relays and one fault relay. One threshold relay can be configured to report the presence of precipitation. A voltage output is provided as standard which can be complimented with an optional current output.

The VPF-510 is available in both low voltage DC and mains AC power configurations. Optional hood heaters are available for use in environments where blowing snow may block the optical windows. The sensor is fitted with 6m fixed cables for all power and signal connections; other cable lengths are available on request.

The VPF-510 is a single lightweight unit that can be easily transported and installed by one person. It is designed for use in all weather conditions and has a wide operating temperature.


Measurement Visibility, MOR or EXCO
Output RS232, Optional RS422/RS485
0 - 10 V
4-20mA (optional)
2 Threshold and 1 Fault Relay
Measurement Principle Forward scatter 45°
Measurement Error 2% at 2,000m
Sensor Power 12 V DC, 24V DC, 120 V AC or 240 V AC (6W Approx)
Hood Heating Power 30W
Window heating and contamination monitoring Fitted
Operating Temperature -50°C to 60°C
Operating Humidity 0 – 100% RH
Protection rating IP66
Sensor Head 4.9 kg DC: 6.1kg AC
Cables Approx. 3 kg

Sales & Support

Contact Biral for more information

To find out more about this instrument or to discuss your application requirements please do not hesitate to contact Biral.

  • email enquiries@biral.com (or use the Request More Information button below the product photograph)
  • Telephone to 01275 847787 (from the UK) or +44 1275 847787 (International)

After Sales Support

Biral offers free advice and technical support for the lifetime of the instruments we sell. Once you have purchased the unit you can always contact us for help using the links on our Technical Support page.


  • VPF Calibration Kit

    Model Number: 70.CAL

    The VPF Calibration kit allows the calibration of all current VPF visibility and present weather sensors to be checked and …

    Read more >