AC Power Measurement
for Modbus Networks,
True Power, kWh
VARs, Power Factor,
Individual Phase Measurements
||1 Phase 2 Wire 230V with neutral
3 Phase 4 Wire 230V/400V
||3-Phase 3-Wire Delta 400V (No neutral)
3-Phase 4-Wire Wye 230/400V
- Delta models, WNB-3D-400-P, work either with or without a neutral connection, but require a line-to-line voltage connection for operating power.
The WattNode Modbus is a kilowatt hour kWh energy and power meter that communicates on a EIA RS-485 network, measures 1, 2, or 3 phases with voltages from 120 to 600 volts Vac and currents from 5 to 6,000 amps in delta (phase to phase) and wye (phase to neutral) configurations.
Our diagnostic LEDs provide a per-phase indication of power (green flashing) and negative power (red flashing) to help troubleshoot connection problems, like reversed CTs, or excessive line voltage. The WattNode Modbus meter also has a red/yellow/green communication LED to indicate traffic, configuration problems, bus contention and other conditions. See the manual for full descriptions.
- Supports floating point and integer registers
- True RMS 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: (Phase A, B, C, and sum of all phases)
- True RMS Energy: Kilo-Watthours kWh (Phase A, B, C, and sum of all phases)
- Reactive Energy: kVAR-hours (All Phases)
- AC Line Frequency
- RMS Voltage: (Phase A, B, C)
- Computed RMS Current: (Phase A, B, C)
- Peak Demand
- Small form factor for easy installation inside most electrical panels, see a sample installation diagram
- Pluggable screw terminals for easy wiring
- 0.5% accuracy nominal (see manual for details)
- True RMS power even with leading or lagging power factor and chopped or distorted waveforms
- Measure variable speed drive pumps and motors
- Uses safe CT's (current transformers), producing 0.333 Vac at rated current.
- Split core CTs for quick installation
- Solid core CTs are less expensive and prevent tampering
- Bus bar CTs for high current applications (standard and custom sizes)
- UL, cUL Listed - Designed and tested for safety and use throughout North America.
- Assembled in USA, qualified under the Buy American provision in the American Recovery and Reinvestment Act of 2009 (ARRA).
- Five year warranty
Web based analysis system
This MODBUS Wattmeter communicates Plug and Play with the eZEio web based monitoring system.
Warning: Hazardous Voltages - Only qualified personnel or licensed electricians should install the WattNode meter and current transformers.
The WattNode® Modbus® meter is available with several factory options at an additional charge. See the WattNode Modbus manual (pdf) for more information and details about the registers mentioned below.
- Option CT=xxx - Pre-assign xxx as the global CtAmps value.
- This can be field configured or overridden using the CtAmps register.
- Option CT=xxx/yyy/zzz - Pre-assign xxx to CtAmpsA, yyy to CtAmpsB, and zzz to CtAmpsC.
- These can be field configured or overridden using the CtAmpsA, CtAmpsB, and CtAmpsC registers.
- Option EP - Factory configure the Modbus RS-485 communications to default to even parity (E81)
- This can be field configured using the ParityMode register if you have meters that were ordered without this option and you need even parity. This can be overridden or turned off in the field by changing the the ParityMode register.
- Option 19K - Factory configure the RS-485 communications 19,200 baud.
- This can be changed in the field by switching the baud rate DIP switch, or by writing to the Baud register. If you write "0" to the BaudRate register, then the DIP switch setting will control the baud rate.
- Option 38K - Factory configure the RS-485 communications to 38,400 baud. Position 8 of the DIP switch will be ignored.
- This can be changed in the field by writing a new value to the BaudRate register. If you write "0" to the BaudRate register, then the DIP switch setting will control the baud rate.
- Option TCP-RTU - Configure the communications to the Modbus TCP-RTU protocol option for use with RS-485 to Ethernet converters (serial device adapters).
- This can be field configured or disabled with the ModbusMode register.
- Option AD - Factory configure the Modbus address.
- This can be changed in the field by by writing a new address to the Address register. If you write 0 (zero) to the Address register, then the DIP switch setting will specify the Modbus address.
Note: All WattNode Modbus meters can have their communication settings restored to factory shipped values by setting all DIP switch positions to "0" for ten seconds. If an communication option has been ordered, the meter will restore to include the settings from any options.
X Terminal Options
These options all utilize the X (auxiliary) terminal on the "MODBUS" connector:
- Option X5 - Provides 5 Vdc at up to 60 milliamps between the C (common) and X (5V) terminals.
- Option IO - Provides a digital input (level sensing and pulse counting) or output (for load shedding and other applications) on the X terminal.
- Option SSR - Provides a solid-state relay (contact closure) output between the X and C terminals for load shedding and other applications.
Contact the factory about the following special options:
- Option 232 - Provide RS-232 I/O in place of RS-485.
- Option TTL - Provide 5V TTL UART I/O in place of RS-485.