Isolation
Isolation is required in many applications where the ground of the signal you want to measure is at a different potential than the instrument's ground. This potential difference in grounds is called a "common mode voltage," or CMV. If the CMV, plus the signal of interest exceeds the instruments full-scale measurement range, then an instrument that provides isolation is required. Further, applications where the CMV plus the signal of interest exceeds the instrument's without-damage-rating (typically 20-30 volts), isolation is required to prevent damage to the instrument. DATAQ Instruments offers many isolated instrumentation solutions, and this Wizard will help you find them. For more information about isolation and the need for it, use these resources: