Measuring 12 ac voltages rms, with a device with a high input impedance, say 10Mohm similar to a fluke meter?

[Alan133]

Hello

Would like to measure 12 voltages, approx 50Vac 50hz, using a device with a high input impedance, say 10Mohm similar to a fluke meter?

A device with a Webserver would be handy?

Many Thanks for any suggestions.