Why Is The Long Common Electrode Always Grounded In The 61F's Floatless Level Controller Connection Diagrams?

There are three reasons for this grounding.
  • Preventing Improper Operation Due to Inductive Noise
    Since there is just a weak current (about 1 mA at 8 VAC) between the 61F Controller and the electrodes, it is easy for inductive noise to cause improper operation when there is no ground.
  • Protecting the 61F Controller from Surge Voltage
    The common electrode must be grounded properly to protect the 61F Controller's internal circuits from surges caused by lightning or other equipment.
  • Preventing Electric Shock
    The ground is needed to prevent electric shock in case of electric leakage.