M-AERI Rain Sensor Notes and Troubleshooting

External rain sensors

  • Two external rain sensors are installed on the post on the railing
  • Blue Vaisala rain sensor
    • Works in cold weather, heather can melt ice off the surface
    • externalRainDetectorSensor (in FTSW Status list) displays a voltage proportional to precipitation level:
      • 3V = very dry
      • 2V = very wet
    • Hatch is triggered based on internal logic output:
      • outsideRainSensor=1 for no precip detected
      • outsideRainSensor=0 for precip detected
    • Sensor may be sensitive to salt deposition
      • Symptoms are:  Hatch is closed when it’s not precipitating AND outsideRainSensor=0 & externalRainDectector <~2.8V
      • The solution is to clean the blue surface of the sensor with distilled water (or wipe down with kimwipe if needed, or use alcohol if needed)
  • Optical rain sensor
    • Should be immune to salt deposition
    • Does not output a voltage: internalRainDetectorSensor=0V (in FTSW Status list)
    • Hatch is triggered based on internal logic output:
      • insideRainSensor=1 for no precip detected
      • insideRainSensor=0 for precip detected
    • Not rated for freezing temperatures.  Heater is not strong enough to melt ice on the surface

Switching external rain sensors

  • Either the Blue Vaisala or Optical rain sensor can be used or not used by connecting or disconnecting it to the cable
  • If a rain sensor is consistently not behaving well in a given set of conditions, it can simply be disconnected
  • Move the wind shield over to the active rain sensor (single hex screw)
  • In this case a new MonitoringConfig.xml file can be installed if desired, so that the FTSW Monitoring display is matched to the rain sensor.  Contact mentor for this