The HSS VF510 visibility sensor is designed for applications where digital and/or analogue signals and/or relay outputs are required from one compact sensor. Part of the established Biral HSS range of visibility sensors the VF510 provides the user with a choice of digital RS232, 422, 485 or analogue voltage or current outputs along with three relay outputs for fog warning and sensor self-test status. The serial communications port is supplied as standard to provide visibility and self-test information. The digital communications port also allows the user to configure the outputs for either Meteorological Optical Range (MOR) or Extinction Coefficient (EXCO) and to set the switching points of the fog relays.