Problem: My Smart Sensor data shows a -888.888 for a good portion of the data file.

-888.888 means that the logger cannot get a response from the Smart Sensor (after launch)

Likely reasons:

  • Sensor is unplugged
  • Corrosion in Smart Sensor housing, due to water damage
  • Corrosion on RJ 12 connector in logger
  • Cut Obus cord (wire connected from logger to Smart Sensor housing)
  • Damaged or disconnected smart extension cable
  • Direct or nearby lightning strike


  • Relaunch the logger and the error may clear - however, we would suggest inspecting the sensor and keeping an eye on the data for future errors.
  • For corrosion: clean off corrosion and let dry. Use a drip loop in the installation so water will not wick into the Smart Sensor.
  • For cut wire: reattach wires matching the wire colors; seal connections and re-launch the logger.
  • For lightning strike: make sure the logger is grounded properly. Electrical code requires 2 x 8 ft rods placed 6 feet apart.


Tech Note
Troubleshooting & Maintenance