With a voltmeter, we can measure a voltage VM between the two. The closer we get to E, the lower the voltage VM becomes. VM is zero at ground rod E. Fig. 3 ‒ Theory behind “fall of potential method” ...

This four-wire trick is useful even if you don’t want to measure resistance with precision. For example, high-current or high-accuracy regulated power supplies use the same trick.

Acromag: Process Transmitters Add Temperature and Resistance Measurement Options. Dec. 18, 2013. ... allows for ±10V, ±5 V, 0-5 V, and 0-10 V. The software allows input scaling as well as ...