schematic help

[xXAxHillbillyXx]

I am currently building this meter and have all but finished it i see this part (circled in red) of the schematic and it just sends me through a loop.. there is a symbol for ground and the letters "GND" I am a little confused on how to hook this part up
**broken link removed**

 

[crutschow]

The meter measures either voltage or current.

To measure voltage, connect the voltage to the two terminals marked "Input 0-70V".

To measure current, connect the "Input 0-70V" connection with the ground symbol to the plus supply voltage for the load. Connect the "Output GND" connection to the load. You do not use the "+" connections to measure current.

CAUTION: For current measurement the circuit being measured can not have a common ground connection with the meter common or the power supply to the meter.

 

[MikeMl]

To measure current, the current has to flow through the 0.47 Ohm current-shunt resistor between the ground symbol and the terminal labeled GND. The PIC is measuring the voltage drop which appears across the shunt. This is a "low-side" current measurement.

 

[crutschow]

If he floats the voltmeter circuit ground then he can measure current in either the high side or the low side of his external circuit.