Floating Operation - Gamry Instruments Interface 1010 Operator's Manual

Floating Operation

The Interface 1010 is capable of operation with cells where one of the electrodes or a cell surface is at earth
ground. Examples of earth-grounded cells include: autoclaves, stress apparatus, pipelines, storage tanks, and
battleships. The Interface 1010 internal ground is allowed to float with respect to earth ground when it works
with these cells, hence the name floating operation.
Instrument performance can be substantially degraded when the Interface 1010 is operated in a floating mode.
The instrument specifications only apply on isolated cells with the Interface 1010 earth-ground referenced (not
floating).
Take special precautions with the cell connections when the Interface 1010 must float. Make sure that all the
cell connections are isolated from earth ground. In this case, you must disconnect the chassis ground terminal
of the Interface 1010 from earth ground.
Finally, ancillary apparatus connected to the Interface 1010 must be isolated. External voltmeters, ammeters,
FRAs, etc. must be isolated. This includes devices connected to the Monitor connector on the Interface 1010's
front panel.
Caution: Cables used with the User I/O connector must be carefully constructed. We do
not recommend connection to the User I/O connector using a 15-conductor shielded cable. The shield
will generally be connected to the metal shell of the User I/O connector on the Interface 1010 end of the
cable. The shield will often be connected to an earth ground on the other end of the cable. Connecting the
grounds in this way destroys the Interface 1010's ability to float and to make measurements on earth-
grounded cells. In extreme cases, this connection can cause damage to the Interface 1010.
Measurement of Small Signals – Floating Operation
65