Specifications

G4500 BLACKBOX PORTABLE OPERATIONAL MANUAL
August 2010
Elspec | PQZip Recording
113
Every harmonic component is being analyzed and compressed indi-
vidually. Zero value components are being skipped. No zero harmonic
components are being evaluated over time and only changes in a value
or angle are being recorded. The resulting data is being compressed
using industry known Lossless compression algorithms.
The compressed harmonic data is being organized in blocks of up to 5
minutes of concurrent cycles and being stored along with the measured
frequency of every cycle and reference time stamps into a PQZip file
residing on the onboard flash memory. The typical compression ratio
expected as a ratio between incoming data volume on block 3 and the
data being stored is 1000:1.
The PQZip files can be downloaded automatically or manually using
the integrated embedded FTP server to the Mobile Analysis Lab or any
other computer system for further storage and analysis.
The compressed data is then reorganized and optimized for fast access
while in a compressed state. The resulting data is stored in the SQL
database for long term storage.
When required, the data is decompressed, recovering a full harmonic
spectrum for each cycle along with the associated time stamps.
The spectral data can further be used to reconstruct any individual cy-
cle’s waveform in the same resolution as at the input module (1) with
accurate time and cycle duration. Any possible electrical parameters
can be calculated based on the data by retrieving precise accuracy and
wave shape.
The waveform displayed by the Investigator application is recon-
structed based on compressed spectral data of every concurrent network
cycle. In addition, virtually any electrical parameter can be calculated
based on that data and displayed at any resolution or time span.
Operation
The PQZip recording does not require any site-specific configurations. As de-
fault, all units leave the factory with PQZip recording being switched ON, and
the instrument will start recording all channels automatically even on the first
power on. The PQZip active state is further defined as a normal operation condi-
tion (refer to Operational Status Indicator on page 26).