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Communication & Verification
DENT Instruments
PowerScout HD
Pre-Processing Aids
The PSHD has several registers that can aid in pre-processing or post-processing data that otherwise
may need secondary operations.
S
NAP
T
HRESHOLDS
The signal-to-noise ratio of the PSHD is above 80 dB at full scale (1 part in 10,000). When the signal
amplitude becomes so small that it is indistinguishable from noise, it is often better to record 0 than a
small, random value. Snap Threshold registers (
Advanced
tab in ViewPoint HD) tell the meter when to
record 0 instead of the measurement result. The factory defaults for CTs are expressed in percent and
have a default value of 0.04% Full Scale. The voltage thresholds are in absolute value, the recommended
minimum voltage is 1.0 volt.
Changing the current Snap Threshold may affect the ANSI C12.20 compliance.
M
ULTIPLIERS
The PSHD has registers that allow potential transformers and series current transformers to be used
with the PSHD meter. These registers allow for transformer winding ratios or other scaling adjustments
to be included in the meter processing to eliminate post process scaling. Adjustments for voltage are
global to the meter while CT’s can be adjusted on a channel-by-channel basis. The multiplier is a
floating-point number and can also be used for post installation calibration if desired. Default value is
1.0. Values below 0.9 are disallowed.
CT
P
HASE
S
HIFTS
Current transformers, like all other transformers, experience a small, magnetizing current that is out of
phase with the measurement current. Phase shift registers are available on a per channel basis and
allow corrections of +/- 4 degrees. ViewPoint HD loads the default phase shift for the CT types available
in the picker list. If no phase shift information is available, enter the accuracy class in degrees (i.e. 1% =
1.0 degree).
D
EMAND
PSHD meters keep track of electrical demand using a 15-minute sliding window. The
Peak Demand
and
Present Demand
registers contain the highest average power consumption in any 15-minute interval and
the average power consumption in the last 15-minute interval, respectively. The Clear Peak Demand
register is used to reset the peak demand detector.
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