FAQ's

What is the resolution of the WattNode^®?

The WattNode's measurement circuitry has a resolution of about 0.15% of reading.

Can I plug or unplug the euroblock connectors when power is applied?

It will not harm the WattNode to plug and unplug the connectors with power applied. Take care that the wires are securely installed in the connector and that you do NOT touch any exposed wires or bare metal. For voltages above 120 VAC we recommend using insulated gloves whenever working with live circuits.

Can I use the WNA-1P-240 models to measure 220 - 240 VAC circuits?

Only if the nominal line-to-neutral voltage is 100 - 120 VAC. The power supply in the WNA-1P-240 models is designed for a maximum of 144 VAC. Connecting 230 VAC between the Neutral and Phase A terminals will destroy the WattNode's power supply. See the application note Measuring 230 VAC Circuits for more information.

Can a 3-phase WattNode measure each phase independently?

Yes, the WattNode Plus has independent phase measurements.

Can I use the WattNode to measure voltage, current, or power factor?

Yes, the WattNode Plus can measure voltage, current, power factor, and frequency.

What is the difference between 'true power' (watts) and 'apparent power' (VA)?

Apparent power is the product of RMS voltage and RMS current. True (or active) power is a time average of the instantaneous power (product of instantaneous voltage and current). For resistive loads the true power and the apparent power will be the same. Inductive loads, such as motors, have a phase shift between the voltage and the current waveforms. This phase shift results in a lower true power measurement than if the voltage and current were in phase. As a result, motors will have higher apparent power than true power. The WattNode measures true power and so for some loads will report a lower power than would be estimated using an ammeter and a voltmeter to compute the apparent power.

I have just hooked up a WattNode and I cannot tell if it is reporting a reasonable power. How can I estimate the power consumption of a load?

Use one of the application notes Estimating Power for Wye Circuits or Estimating Power for Delta Circuits to help compute the estimated power of a load. Then compare the results with the output of the WattNode. If they substantially disagree, you will need to troubleshoot the WattNode installation (see the WattNode Installation Manual for troubleshooting).

I don't see your WattLog software available for sale anymore.

We have discontinued sales of WattLog because it was not LNS compatible and because we are introducing a new line of LonWorks WattNodes with improved datalogging that are not supported by WattLog. If you have further questions, please call us.

What should I do if my question is not on this list?

Please let us know by sending e-mail to techsupport@ccontrolsys.com.

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