5-4
5
Specifications
EPQ DataNode Series User’s Guide
Theory of operation and detailed hardware
description
Data Acquisition
Each input signal is processed by three separate paths. A
straight through path goes through a low pass filter to the
A/D and is used for RMS measurement. The other paths
lead to positive and negative peak detectors for impulse
capture. These are read and reset at the same rate as the
RMS samples, 128 samples per cycle. Dual A/D convert-
ers convert voltage and current signals simultaneously to
prevent any phase shift errors from being introduced in
the power calculations.
Triggering
Voltage and current thresholds can be used to trigger 16
cycle pre/post/fault cycles of waveforms for every chan-
nel per event. This includes triggering on current tran-
sients, which may be the only way to detect voltage tran-
sients where surge-suppression devices are used on the
circuit. VERY HI, HI, LO, VERY LO and Deadband
(step or sensitivity changes) thresholds are settable on an
individual phase or three phase basis, in absolute or per-
cent of fixed or floating nominal. This versatility allows
for maximum use of processing speed and memory, by
collecting and analyzing only the data that is important
to the equipment susceptibility or performance stan-
dards, instead of filling the memory with uneventful or
meaningless data.
In addition to the sag, swell, interruption and transient
capture, the user can select parameters for trending at
user-selected time intervals. This includes min/max/aver-
age values over each interval updated once per second.
Certain power parameters, such as demand, also have sta-
tistical values computed over a day, week and month inter-
vals. Harmonic and interharmonic calculations comply
with the 6000-4-7 and other standard 200-millisecond
windows, including fundamental phase angles and distor-
tion levels. This information is also available for trending
and statistical analysis.
Data and information from the EPQ DataNodes are sent to
the InfoNode via a high-speed Ethernet link using the
standard UCA-2 communication protocol. This protocol is
also used from the InfoNode to the DataNodes for set-up,
including time-syncing to GPS source in the InfoNode.
The InfoNode provides the user interface for accessing the
data and information from the DataNodes via a conven-
tional web browser. Additional DataNodes can be easily
added to the network. Operation of different types of
DataNodes and the InfoNode are covered in their own
separate user's guides.
EPQ Models
The 5530 EPQ DataNode consists of a measurement unit
with external voltage and current pods. The voltage pods
are rated for 600Vrms, while the current pods are 5A
nominal, with 5X overcurrent capability. The pods are
connected to the measuring unit with 3 foot cords, to
allow the pods to be placed in line with existing wiring.
The 5520 EPQ DataNode has internal voltage and current
transducers with the same operating ranges.
