ION meters such as the ION9000, ION7400, and PM8000 require both voltage and current inputs to be connected in order to function correctly and provide meaningful measurement data. Operating the device with only current inputs and no voltage inputs is an incorrect wiring configuration that will cause the meter to display no or incorrect data (e.g., “N/A,” zero, or values that appear offset, such as half the expected value). This occurs because the meter cannot calculate parameters such as power, energy, power factor, phase angles, or power quality indicators without valid voltage references.

While supplying auxiliary control power allows the meter to power on and display current readings when only the current inputs are connected, all voltage‑dependent functions including voltage measurement, power and energy calculations, power factor, phase angle, and voltage‑based power quality analysis will be unavailable or will display zero/invalid values.