10-04-2017, 08:30 PM
In this micro-controller-based line voltage monitor instrument, an AC signal-under-test is sensed from the line voltage via a broadband isolation transformer, and processed to provide RMS and fast peak signals. These are then converted to digital form in the micro-controller in a sampling process synchronized from a zero-cross signal detected from the AC test voltage. An LED display with 40 LED segments provides resolution of one volt RMS per LED segment. An internal real time clock enables storing of time-related data regarding the quality of the power line voltage levels. The instrument can be connected in two-way communication with an external computer or control terminal to provide extended functionalities.
The major parts of the system are:
-input coupling means for supplying an AC signal
-precision half-wave detector, receiving as input the AC signal and giving as output the precision half wave rectified waveform.
-peak detector, receiving as input the AC signal.
-display system, including , processing circuitry, user controls, display device and display drive circuitry. RMS and peak values of the power line voltage are displayed simultaneously.
Application:
unacceptable anomalies that can disrupt, damage and even destroy valuable electronic equipment,fro example, computers used in business, industry and communications , can be detected. It can be used for quality control of a.c. electrical power supplied to a wide range of consumers. It provides the capability of monitoring, logging, accessing and displaying a set of parameters and logging functions, such as RMS and peak readings, time durations and intervals, directly from the PLM instrument panel.
The detailed description and drawings can be found at:
http://freepatentsonline6198403.pdf
Also there is a Power Line Monitor IC MID400 which are used in power-to-logic applications.
The MID400 Power Line Monitor
The MID400 is an optically isolated AC line-to-logic interface
device for monitoring ON or OFF status of an AC power
line.It is used in power-to-logic interface applications such as
industrial controls medical equipment, computers and other
fail-safe type monitor systems in which status information
about the AC line is essential.
full seminar report download :
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