4 Overview
Overview
Congratulations on your purchase of the WattNode
®
Pulse watt/watt-hour transducer/meter.
It accurately measures energy and power in a compact package. The WattNode meter can fit
in existing electric service panels avoiding the costly installation of sub-panels and associated
wiring. It is designed for use in demand side management (DSM), sub-metering, and energy
monitoring applications. The WattNode meter generates pulses proportional to total watt-hours.
The pulse rate or frequency is proportional to the instantaneous power. Models are available for
single-phase and three-phase, wye and delta configurations for voltages from 120 Vac to 600 Vac
at 50 and 60 Hz.
Pulse Outputs
The WattNode meter generates pulse outputs using one or more optoisolators (also called
photocouplers). These provide 5000 Vac of electrical isolation. The pulse outputs can interface to
monitoring or data logging hardware without concerns about interference, ground loops, shock
hazard, etc.
The standard Pulse WattNode meter makes bidirectional power measurements (energy consump-
tion and energy production). It can be used for conventional power and energy measurement as
well as for net metering and photovoltaic (PV) applications.
●
Option P3
- The per-phase measurement option measures one, two, or three separate
branch circuits with a single meter, saving money and space.
●
Option PV
- The photovoltaic option measures residential PV systems. One WattNode meter
measures the bidirectional total house energy, and the PV (or wind) generated energy. See
Manual Supplement MS-10: Option PV (Photovoltaic)
for details.
●
Options DPO
- The dual positive outputs option behaves exactly like the standard bidirec-
tional model, but with the addition of a second positive pulse output channel (on the
P3
output terminal). This allows you to connect to two devices, such as a display and a data
logger. See
Manual Supplement MS-11: Option DPO (Dual Positive Outputs)
for details.
See
in the
section below for details and more options.
Diagnostic LEDs
The Pulse WattNode meter includes three diagnostic LEDs—one per phase. During normal
operation, these LEDs flash on and off, with the speed of flashing roughly proportional to the
power on each phase. The LEDs flash green for positive power and red for negative power. Other
conditions are signaled with different LED patterns. See the
Installation LED Diagnostics (p.
section for full details.
Current Transformers
The WattNode meter may use split-core (opening), solid-core (toroidal), and flexible Rogowski
current transformers (CTs), with a full-scale voltage output of 333.33 mVac and opening widths
ranging from 0.3 in (7.6 mm) up to 12 in (305 mm) or Rogowski lengths up to 48 in (1220 mm).
Split-core and Rogowski CTs are easier to install without disconnecting the circuit being mea-
sured. Solid-core CTs installation requires that you disconnect the circuit to install the CTs.
Additional Literature
●
WattNode Advanced Pulse - Quick Install Guide
●
Manual Supplement MS-10: Option PV (Photovoltaic)
●
Manual Supplement MS-11: Option DPO (Dual Positive Outputs)
●
Manual Supplement MS-17: Option PW (Pulse Width)
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