WattNode® Logger for LonWorks

AC Power Measurements and Logging for LonWorks Networks:

Real Power (kW) & Energy (kWh)
Net Metering
Reactive Power (VAR)
Power Factor
Individual Phase Measurements

WattNode Logger for LonWorks

The WattNode Logger is a kilowatt hour (kWh) energy meter that communicates on a LonWorks network, and can log 24,000+ measurement records in non-volatile memory. The WattNode Logger measures 1, 2, or 3 phases with voltages from 120 to 600 volts Vac and 5 to 6,000 amps in delta (phase to phase) and wye (phase to neutral) configurations.


  • Net Real Energy: kilowatt-hours – kWh (Phase A, B, C, sum of all phases)
  • Positive Real Energy: kilowatt-hours (sum of all phases)
  • Bidirectional Real Power: Watts (Phase A, B, C, and sum of all phases)
  • Reactive Power: VARs (Phase A, B, C, and sum of all phases)
  • Power Factor: PF (Phase A, B, C, all phases)
  • Reactive Energy: kVAR-hours (All Phases)
  • AC Frequency
  • RMS Voltage: (Phase A, B, C)
  • Computed RMS Current: (Phase A, B, C)
  • Demand
  • Peak Demand

Quantities Logged

  • Date and Time
  • Net Energy (A, B, C and Sum)
  • Reactive Energy (Sum)
  • Positive Energy (Sum)
  • Real and Reactive Power (A, B, C and Sum)
  • Voltage, Current and Power Factor (A, B, C)
  • Demand


  • Logging intervals from 1 minute to 12 hours, allows logging up to 250 days of 15-minute data
  • Supports LonWorks TP/FT-10 free topology twisted-pair network using Echelon’s® LonTalk® (ANSI/CEA-709.1-B-2002) network protocol.
  • LonMark 3.4 Certified
  • Small form factor for easy installation inside most electrical panels, see a sample installation diagram.
  • Pluggable screw terminals for easy wiring
  • 0.5% nominal accuracy (see manual for details)
  • True RMS power even with leading or lagging power factor and chopped or distorted waveforms
  • Monitors variable speed drives, pumps, and motors
  • Safe CT’s (current transformers), output 333 mVac at rated current.
    • Split core CTs for quick installation
    • Solid core CTs are less expensive and prevent tampering
    • Custom and standard Bus Bar sized CTs
  • Assembled in USA, qualified under the Buy American provision in the American Recovery and Reinvestment Act of 2009 (ARRA).
  • Five year warranty

Safety Note

Warning: Hazardous Voltages – Only qualified personnel or licensed electricians should install the WattNode meter and current transformers.

LonWorks is a registered trademark of Echelon Corporation