Getting "Range Error" on the IV Analyzer with ELVIS III

Updated Oct 14, 2019

Reported In

Hardware

  • NI ELVIS

Software

  • Measurements Live
  • NI ELVIS III Software Bundle

Issue Details

I am running an IV sweep on a diode with the IV analyzer tool for the ELVIS III. The sweep does not finish and shows as Range Error. 

Solution

This is an expected behavior from the ELVIS III. The error appears as we're running into the 10V limit of the IV Analyzer. As the voltage sweep proceeds the instrument will attempt to apply a voltage across the whole circuit (both the diode and the internal series resistor) such that the voltage measured just across the diode alone equals the desired voltage step of the sweep. At a certain point, as that voltage gets close to the forward voltage of the diode, more current is being drawn and the instrument's voltage source is unable to drive the level needed to reach the next step in the sweep. At that points it throws the error. This is sometimes referred to as saturation of your measurement range. This is actually mentioned briefly in the manual for the measurement VI under the series resistance input because it is relevant for choosing a proper series resistance range.

You'll notice that as we increase the series resistance of the measurement the current where the sweep stop starts to decrease. This is because increasing this resistance lowers the current across the circuit the diode's characteristics are such that we reach this voltage saturation point regardless of our series resistance setting. Ultimately, we recommend to check the diodes specification sheet  and adjust the IV Analyzer's sweep ranges accordingly.