The Hi and Lo terminals are used to make DC and AC voltage measurements. The GX2065 can make DCV measurements from 0.1µV to 300 V and ACV measurements from 0.1µV to 300V RMS, 425 V peak. The input circuitry presents the following input resistance values for DC and AC operation.
DCV input resistance:
100V and 300V ranges: 10M ohms
100mV, 1V, and 10V ranges: >10G ohms
ACV input impedance: 10M ohms
As shown in the block diagram, both the Hi and Lo input terminals are protected and isolated to 300V between the Hi and Lo terminals and the Lo and chassis ground potentials. Internal switching routes the Hi signal to the converter (DCV measurements) or to the AC circuitry for AC measurements. An internal reference provides a transfer standard for measurement traceability to an external standard. AC RMS conversion uses a high-speed A/D in conjunction with on-board RMS processing algorithm.