Digital ac monitor

Patent · 09 June 1987

OSTI ID:866275

Hart, George W ^[1]

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1. Natick, MA

An apparatus and method is provided for monitoring a plurality of analog ac circuits by sampling the voltage and current waveform in each circuit at predetermined intervals, converting the analog current and voltage samples to digital format, storing the digitized current and voltage samples and using the stored digitized current and voltage samples to calculate a variety of electrical parameters; some of which are derived from the stored samples. The non-derived quantities are repeatedly calculated and stored over many separate cycles then averaged. The derived quantities are then calculated at the end of an averaging period. This produces a more accurate reading, especially when averaging over a period in which the power varies over a wide dynamic range. Frequency is measured by timing three cycles of the voltage waveform using the upward zero crossover point as a starting point for a digital timer.

• Research Organization: MASSACHUSETTS INST OF TECH
• DOE Contract Number: AC02-76ET20279
• Assignee: Massachusetts Institute of Technology (Cambridge, MA)
• Patent Number(s): US 4672555
• Application Number: 06/662,392
• OSTI ID: 866275
• Country of Publication: United States
• Language: English

Related Subjects

/700/324/702/
accurate
analog
apparatus
averaged
averaging
calculate
calculated
circuit
circuits
converting
crossover
current
cycles
derived
digital
digital form
digitized
dynamic
dynamic range
electrical
electrical parameter
electrical parameters
especially
format
frequency
intervals
measured
method
monitor
monitoring
non-derived
parameters
period
plurality
power
predetermined
predetermined interval
produces
provided
quantities
range
reading
repeatedly
samples
sampling
separate
starting
stored
storing
timer
timing
upward
varies
variety
voltage
voltage waveform
waveform
wide
wide dynamic
zero