What is floating ground?

The term floating ground (FG) is used to describe an option that allows for very accurate ground referenced load current measurements to be made.

Whatever current flows out of the high voltage output of a supply, must return via the ground referenced return path. This current must return back to its original source, the high voltage output section inside the supply.

The FG option isolates all of the analog grounds inside the supply and brings them to one point: usually provided on the rear of the power supply. If a current meter is connected between this FG point and chassis ground, the actual high voltage return current can be measured in a safe ground referenced fashion.

Essentially, the analog grounds inside the supply are "floated" up a few volts to allow for this measurement. This option is only intended to allow for a ground referenced current measurement, so the actual maximum voltage the internal analog ground "floats" to, is usually limited to 10 volts maximum.

It is important to note that all control and monitoring circuitry are also floated on top of the FG terminal voltage. Users of this option must provide isolation from the FG terminal to chassis ground. Higher voltages may be available depending on the model selected. Please contact our Sales Department for more information.