First, and foremost: ‘–DC1’ models do not provide electrical isolation between the DC SUPPLY that powers the ammeter and the power supply that powers the load circuit. This important point must be considered when using ‘–DC1’ models in dual-supply applications similar the one shown in the DCA-20PC data sheet’s Figure 2B diagram.
‘-DC4’ models include an internal dc/dc converter which provides a minimum of 500V of isolation between the DC SUPPLY and the load power supply in dual-supply applications. ‘–DC4’ models are also recommended when both positive and negative load currents must be displayed. Lastly, ‘-DC4’ models must be used in single-supply applications which have the shunt connected to the high-side (+) terminal of the DC SUPPLY.