AVR-Chat

Hello all,

I am going to measure the current (0-500mA) on a system. i will be 
using a current sense resistor, and an op-amp then i use ADC to 
measure the opm-amp output. But my problem is that the the line is 
high voltage (70 V). I am thinking to isolate the ground of the the 
line and the ground of my monitoring box. In this case, the monitoring 
box will not sence the 70 volt line as 70 volt, but will just measure 
the voltage drop accross the current sense resistor. A idea on how to 
measure current on high voltage systems is highly appreciated?

regards,
mago