Common wiring examples

Triaxial cabling, low current measurement

Traditional configuration for triax cable is such that inner conductor is connected to output high terminal, middle conductor is connected to guard terminal following output high and outer shell is connected to output low terminal ( see eg. Low Level Measurement Handbook, figure 2-14 ).

As Strix uses essentially what is low-side current measurement, conventional wiring approach will not provide wanted results. A guard following Drive+ potential will create a voltage difference between guard layer and Drive- and thus generate leakage current flowing from guard to Drive-.

In order to minimise leakage between Drive+ and Drive- ( and between rest of the system ), guarding should be done by connecting the measurement guard to Strix system ground via the SMA connector shroud. As Strix uses a transimpendace amplifier to measure current, the Drive- terminal is not a "true ground" but it is driven to ground by the circuitry. Therefore in order to minimise any stray currents etc, voltage difference between Drive- and system ground should be kept as small as possible.

Three-electrode electrochemical cell

Standard three-electrode cell consists of reference electode, working electrode and counter electode. Voltage between reference electrode and working electode is measured / adjusted and current flowing between working electrode and counter electrode is measured.

In order to accomplish this behaviour, 4-wire mode is used. Sense+ is connected to working electrode and Sense- is connected to reference electrode. Drive+ is connected to working electrode and Drive- to counter electrode.