These isolators isolate the DC input signal from the DC Output signal, which is directly proportional to the input signal. There are two levels of isolation offered, the M100-DA1 / DV1 / DV2 have 4kV isolation and the M100-DA1I / DV1I / DV2I have 1.5kV isolation. A wide range of both D.C. Current and voltage inputs are offered. Typically, these isolators can be used to prevent earth loops, which occur when a measuring source, that is earthed, is connected to a computer or data logger that is also earthed. Another common use is to provide isolation on the inputs to a PLC. All of the above isolators have either A.C. or D.C. Auxiliaries which means they have an advantage over loop-powered units, in that if for any reason the output lead should become disconnected, the input will not be saturated.