Hi!

Voltage-to-voltage signal conditioner:
http://www.ayainstruments.com/products3.html


Other solution:

The link below is the schematic of an uninterrupted power supply.
See the signal IN-RECT on the schematic page 1 (Top left corner).
See the same signal IN-RECT on the schematic page 2. (Top left corner).

http://www.eserviceinfo.com/download...400i_600i.html

Be careful with AC Mains voltage!

If you try it, let us know how it works.

Luciano