The BasicLine BL541/BL542 Loop-Powered Isolator and Signal Conditioner for standard signals is extremely versatile.  This unit is loop-powered and does not require a separate power supply which reduces the wiring effort by 1/3.  It has a low voltage drop of 1.7V and it comes both 1 and 2 channel versions.  This Knick unit comes with some of the highest reliability in the industry backed by a 3 year warranty.